Dry-mix cementitious composition and mortar formed therefrom for additive manufacturing of multi-layered structures

Abstract

The present technology relates to a dry‑mix composition for additive manufacturing, the dry‑mix composition comprising at least one cementitious binder, at least one filler comprising fine aggregates, at least one superplasticizer, and at least one viscosity modifier. Also described are a mortar formed by combining the dry‑mix composition with water, a process for producing the mortar, and a multi‑layered structure fabricated by additive manufacturing of layers of the mortar. Further described is the use of the dry‑mix composition for producing a multi‑layered structure by additive manufacturing.

Description

DRY-MIX CEMENTITIOUS COMPOSITION AND MORTAR FORMED THEREFROM FOR ADDITIVE MANUFACTURING OF MULTI-LAYERED STRUCTURESRELATED APPLICATION

[0001] This application claims priority under applicable laws to United States provisional application No. 63 / 762.546 filed on February 24, 2025, the content of which is incorporated herein by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The present invention relates generally to dry-mix formulations for cementitious materials and, more particularly, to a dry-mix composition and corresponding mortar specifically engineered for use in additive manufacturing (3D printing) of multi-layered structures.BACKGROUND

[0003] Conventional concrete and mortar compositions are generally not suitable for extrusion- based additive manufacturing of multi-layered structures. Traditional mixes typically exhibit inadequate rheological properties, such as inconsistent flowability, insufficient buildability, and extended setting times, which hinder layer deposition and the ability of freshly extruded layers to maintain their intended geometry.

[0004] Various alternative fabrication techniques, such as sand casting, die casting, forging, and conventional bricklaying, have been employed for constructing structural elements. However, such methods often suffer from significant limitations, including substantial setup requirements, long lead times, heavy dependence on manual labor, and limited potential for automation.

[0005] Accordingly, there remains a need for improved cementitious compositions that address at least some of the deficiencies associated with traditional mortar and concrete mixes, including the drawbacks previously noted with respect to their rheological behavior, buildability, and suitability for additive manufacturing processes.SUMMARY

[0006] There is provided a novel dry-mix composition tailored for additive manufacturing, such as 3D printing in construction. Traditional concrete and mortar mixes present challenges in additive manufacturing due to their flow properties, setting times, and structural integrity when extruded. The dry-mix composition is optimized to provide a resulting mortar having an adequate balance between workability and stability for additive manufacturing applications, thereby enabling the mortar to be deposited in successive layers while maintaining shape and load-bearing capacity.

[0007] In order to print a multi-layered structure, the dry-mix composition is configured to be rapidly mixable with a reduced amount of water such that the mortar can be used in a continuous mixing system. The dry-mix composition is further configured to produce a mortar that is pumpable through a nozzle having a relatively small diameter. The dry-mix composition is also configured to provide a rheological profile that enables retention of the layer shape upon extrusion from the printing nozzle. In addition, the drymix composition is configured to provide a mortar having a chemical composition suitable for buildability during layer-by-layer deposition onto previously deposited material.

[0008] The dry-mix composition comprises at least one binder comprising a cementitious binder; at least one filler comprising fine aggregates, at least one superplasticizer, and at least one viscosity-modifying agent (or viscosity modifier). Upon mixing with water to form a substantially homogeneous mortar, the dry-mix composition exhibits enhanced pumpability, printability, buildability, open time, and durability, thereby facilitating the production of three-dimensional, multi-layered structures.

[0009] In one aspect, there is provided a dry-mix composition for additive manufacturing, the dry-mix composition including:i. at least one binder comprising a cementitious binder;ii. at least one filler comprising fine aggregates;iii. at least one superplasticizer; andiv. at least one viscosity modifier.

[0010] In some embodiments, the cementitious binder of the dry-mix composition comprises cement, optionally selected from Type I, Type II, Type III, Type IV, Type V, Type IL, or Type IP cement.

[0011] In some embodiments, the cementitious binder serves as a primary binder, and the dry-mix composition further includes a secondary binder, which may be cementitious or non-cementitious.

[0012] In some embodiments, the fine aggregates comply with the fine-aggregate size requirements of ASTM C33 / C33M-23. In some embodiments, the fine aggregates comprise or consist of sand.

[0013] In some embodiments, the at least one filler comprises the fine aggregates in combination with at least one additional filler. The additional filler may be selected from ground calcium carbonate, silica fume, perlite, expanded shale, pumice, plastic aggregates, organic aggregates, recycled concrete aggregates, or any combination thereof.

[0014] In some embodiments, the at least one superplasticizer comprises a synthetic polymer.

[0015] In some embodiments, the at least one superplasticizer comprises a polycarboxylate-ether-based superplasticizer.

[0016] In some embodiments, the at least one viscosity modifier comprises clay, silica fume, cellulose ether, fly ash, starch ether, biopolymer gums, slaked lime, or any combination thereof.

[0017] In some embodiments, the dry-mix composition further comprises at least one setting accelerator, which may be selected from calcium sulfoaluminate cement, calcium aluminate cement, calcium nitrate, calcium nitrite, calcium formate, lithium carbonate, lithium sulfate, aluminum-based compounds, or any combination thereof.

[0018] In some embodiments, the dry-mix composition further includes a hydrophobic chemical agent. In some embodiments, the hydrophobic chemical agent is selected from calcium stearate, silanes, siloxanes, or any combination thereof.

[0019] In some embodiments, the dry-mix composition further includes at least one of a superabsorbent polymer, a pigment, fibers, or an environmentally beneficial additive.

[0020] In some embodiments, a weight ratio of the at least one filler to the at least one binder is between about 1.5 and about 2.5.

[0021] In some embodiments, the superplasticizer is present in an amount between about 0.2 wt.% and about 1 wt.% based on the total weight of the dry-mix composition.

[0022] In some embodiments, the viscosity modifier is present in an amount between about 1 wt.% and about 15 wt.% based on the total weight of the dry-mix composition.

[0023] In another aspect, there is provided a mortar comprising water and the dry-mix composition described herein, wherein the water is present in an amount between about 8 wt.% and about 25 wt.% based on the total weight of the dry-mix composition.

[0024] In some embodiments, the water is present in an amount between about 14 wt.% and about 18 wt.% based on the total weight of the dry-mix composition.

[0025] In some embodiments, a weight ratio of water to binder in the mortar is at most about 0.4 to 0.7.

[0026] In some embodiments, the mortar has a flowability between about 80% and about 140%, as measured in accordance with ASTM C1437.

[0027] In some embodiments, the mortar has a cone penetration between about 50 mm and about 80 mm, measured in accordance with ASTM C780-23 Annex A1 approximately 5 minutes after mixing water and the dry-mix composition.

[0028] In some embodiments, the mortar exhibits a 24-hour compressive strength greater than about 1,500 psi and a 28-day compressive strength greater than about 5,000 psi, as measured in accordance with ASTM C109.

[0029] In another aspect, there is provided a use of the dry-mix composition as described herein for producing a multi-layered structure by additive manufacturing.

[0030] In another aspect, there is provided a multi-layered structure produced by additive manufacturing of layers of the mortar as described herein.

[0031] In another aspect, there is provided a process for producing a mortar for additive manufacturing of multi-layered structures, the process comprising mixing water and the dry-mix composition as described herein, wherein the water is mixed with the dry-mix composition in an amount between about 8 wt.% and about 25 wt.% based on the total weight of the dry-mix composition.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 illustrates representative test samples (50 mm x 50 mm mortar cubes) after completion of 25 freeze-thaw cycles while immersed in a brine solution containing 10% by mass calcium chloride in water. The samples were prepared and tested in accordance with PA Test Method No. 633.DETAILED DESCRIPTION

[0033] The following detailed description and examples are illustrative and should not be interpreted as further limiting the scope of the invention. On the contrary, it is intended to cover all alternatives, modifications and equivalents that can be included as defined by the present description. The objects, advantages and other features of the present invention will be more apparent and better understood upon reading the following non-restrictive description and references made to the accompanying drawings.

[0034] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which the present technology pertains. The definition of some terms and expressions used herein is nevertheless provided below for clarity purposes.

[0035] When the term “about” is used herein, it means approximately, in the region of or around. When the term “about” is used in relation to a numerical value, it modifies it; for example, by a variation of 10% above and below its nominal value. This term can also take into account the rounding of a number or the probability of random errors in experimental measurements, for instance, due to equipment limitations.

[0036] When a range of values is provided, the stated range includes its lower and upper limits unless expressly indicated otherwise. Furthermore, all intermediate values,sub-ranges, and individual values within the stated range are considered to be expressly included as if individually recited.

[0037] It should also be noted that the use of the indefinite article “a” or “an” to introduce an element is not intended to mean “only one” unless explicitly stated. Rather, the terms “a” and “an” should be construed to mean “one or more”. Similarly, when the specification states that a feature, step, component, or characteristic “may”, “might”, “can”, or “could” be included, such language indicates that the feature is optional and not required in every embodiment.

[0038] In the present description, the term “embodiment” refers to an example or implementation of the invention. The reference to “one embodiment”, “an embodiment”, or “some embodiments” does not imply that the embodiments described necessarily refer to a single and same embodiment. Although various features may be described together for ease of presentation, such features may be implemented individually or in any suitable combination. Conversely, features described separately may also be implemented together in a single embodiment.

[0039] As used herein, the term “comprising” is intended to be interpreted in a non-limiting sense and should be understood to mean “including but not limited to”, thereby permitting the presence of additional elements, components, or steps not expressly recited.

[0040] There is provided a dry-mix composition suitable for additive manufacturing, and in particular for three-dimensional (3D) printing of multi-layered structures. The dry-mix composition results from a deliberate selection of constituents tailored to produce, when combined, a printing mortar exhibiting both adequate pumpability and smooth flow through a printer nozzle, while retaining sufficient buildability to maintain its shape after extrusion. In some embodiments, the dry-mix composition includes a cementitious binder such as cement, a filler including fine aggregates, a superplasticizer, and a viscosity-modifying agent.

[0041] As used in the present specification, the term “composition” can encompass a dry-mix composition which may be in a mixed, and preferably uniformly mixed, state such that it is ready for use upon addition of water to form a printable and curable mortar. The dry-mix composition may also be referred to as a mortar composition or adry-mix mortar composition. In addition, the term “dry-mix composition” encompasses combinations of ingredients that are fully mixed, partially mixed, or provided in a pre-mix form in which one or more constituents are not yet combined.

[0042] As used in the present specification, the term “mortar” may be referred to as a printing mortar or additive manufacturing mortar, reflecting its use in additive manufacturing processes. The mortar is obtained by combining water with the dry-mix composition as described herein, thereby forming a wet paste that is extrudable for 3D-printing applications. In some embodiments, water is added to the dry-mix composition in an amount ranging from about 8 wt.% to about 25 wt.% based on the total weight of the dry-mix composition. Exemplary intermediary ranges include from about 10 wt.% to about 22 wt.%, from about 12 wt.% to about 20 wt.%, from about 13 wt.% to about 19 wt.%, and from about 15 wt.% to about 18 wt.%. In a particular embodiment, water is added in an amount from about 14 wt.% to about 18 wt.% based on the total weight of the dry-mix composition.

[0043] As used in the present specification, the term “cementitious” refers to materials exhibiting cement-like properties. For example, the dry-mix composition includes a cementitious binder, meaning a binder that is cement and / or a material possessing cement-like binding characteristics.

[0044] As used in the present specification, the expression “additive manufacturing”, when applied to the dry-mix composition, refers to a composition capable of producing a mortar that may be printed using known additive manufacturing techniques to form structures.

[0045] For additive manufacturing applications, the present dry-mix composition is formulated to produce a mortar exhibiting a flowability between about 80% and about 140%, as measured in accordance with ASTM C1437-20. Exemplary intermediary flowability ranges include from about 85% to about 135%, from about 90% to about 130%, from about 95% to about 125%, and from about 100% to about 110%. In a particular embodiment, the dry-mix composition is formulated to produce a mortar exhibiting a flowability between about 100% and about 110%. The mortar further exhibits a cone penetration between about 50 mm and about 80 mm, as tested in accordance with ASTM C780-23 Annex A1. Additional exemplary intermediary cone penetrationranges include from about 55 mm to about 75 mm and from about 58 mm to about 72 mm. In a particular embodiment, the cone penetration is between about 60 mm and about 70 mm.

[0046] In the present specification, the term “structure” refers to any structural or non-structural object or system produced by depositing and curing the dry-mix composition through an additive manufacturing process. The resulting structure is therefore a multi-layered element formed through a layer-by-layer deposition technique. When a mortar produced from the dry-mix composition is used in 3D-printing, the cured or curing material of the printed structure may be referred to as a mortar, 3D-printed mortar, concrete, or 3D-printed concrete, depending on the particle size distribution of the aggregates included in the dry-mix composition used to print the structure.Binder

[0047] The dry-mix composition includes at least one binder responsible for the setting and hardening of the dry-mix composition. The at least one binder includes or consists of a cementitious binder, which serves as the primary binder. In one embodiment, the binder system of the dry-mix composition consists solely of the cementitious binder. In another embodiment, the binder system includes the cementitious binder in combination with an additional secondary binder, which may be either cementitious or non-cementitious.

[0048] The cementitious binder may include cement. In some embodiments, the cementitious binder includes Portland cement. In particular embodiments, the cementitious binder includes at least one of Type I, Type II, Type III, Type IV, Type V, Type IL, and Type IP cement. In some embodiments, the cement type is selected such that a mortar prepared from the dry-mix composition exhibits at least one of: (i) a 24-hour compressive strength of greater than about 1,500 psi, and (ii) a 28-day compressive strength of greater than about 5,000 psi, as measured in accordance with ASTM C109.

[0049] In a particular embodiment, the cementitious binder is Type IL cement. Type IL cement can serve as the primary binder and can provide strength, stiffness, and durability in the hardened mortar. As a Portland-limestone cement, Type IL can also enhance sustainability by reducing clinker content and may improve workability. Inadditive-manufacturing applications, Type IL cement can support suitable setting behavior, strength development, and overall structural performance of the printed layers.

[0050] In some embodiments, the secondary binder includes a fast-setting binder configured to accelerate curing and / or early strength development of the dry-mix composition, thereby enhancing structural stability of a printed article as successive layers are deposited. The fast-setting binder may include a fast-setting cement. In particular embodiments, the fast-setting cement includes at least one of calcium sulfoaluminate cement and calcium aluminate cement. In some embodiments, the fastsetting binder is present in an amount effective to increase early-age strength relative to an otherwise identical composition lacking the fast-setting binder.

[0051] In some embodiments, the dry-mix composition includes the cementitious binder as defined herein as the primary binder and at least one secondary binder that is non-cementitious. The secondary binder may include at least one of a geopolymer binder, fly ash, a natural pozzolan, Type S lime, or any combination thereof. In some embodiments, the secondary binder is present in an amount effective to modify at least one of setting time, workability, rheology, strength development, durability, or shrinkage characteristics of the dry-mix composition.Filler

[0052] The dry-mix composition further includes at least one filler. In some embodiments, the at least one filler comprises aggregate particles having a particle size distribution selected to promote smooth flow of the dry-mix composition through a nozzle of a three-dimensional (3D) printing apparatus, while maintaining mechanical strength and reducing shrinkage of the hardened composition. In some embodiments, the aggregate comprises fine aggregate. In particular embodiments, the fine aggregate conforms to the gradation requirements of ASTM C33 / C33M-23 for fine aggregate. In some embodiments, the aggregate conforms to ASTM E11 with respect to sieve designation. In some embodiments, the particle size distribution of the aggregate is within the ranges set forth in Table 1.Table 1 - Exemplary Particle Size Distribution for Fine Aggregate

[0053] In some embodiments, the aggregate comprises sand. In particular embodiments, the aggregate consists essentially of sand. In further embodiments, the aggregate consists of sand. The sand may comprise natural sand, manufactured sand, or any combination thereof.

[0054] In some embodiments, the dry-mix composition includes at least one filler including sand as the aggregate and at least one additional filler composed of fine particles. The additional filler may comprise at least one of ground calcium carbonate, silica fume, recycled concrete aggregate, or any combination thereof. Such fine particles may enhance particle packing, improve rheology, or contribute to strength development of the printed material. As used herein, the term “fine particles” refers to particles having a maximum particle size of about 150 pm. In some embodiments, the fine particles have a particle size less than or equal to about 150 pm as measured by sieve analysis.

[0055] In some embodiments, the at least one filler may be selected to provide a lightweight printable composition. Depending on application requirements, the at least one filler may include sand in combination with at least one lightweight filler. In some other embodiments, the at least one filler consists essentially of, or consists of, the lightweight filler. The lightweight filler may comprise at least one of perlite, expanded shale, pumice, plastic aggregates, organic aggregates, or any combination thereof. In some embodiments, the lightweight filler is present in an amount effective to reduce the density of the hardened composition relative to an otherwise identical composition lacking the lightweight filler.

[0056] In a particular embodiment, the at least one filler comprises concrete sand. Concrete sand can serve as the fine aggregate and provides dimensional stability, rheological balance, and cost efficiency. It may contribute to buildability by imparting sufficient body and shape retention to the fresh mortar. In additive-manufacturingapplications, concrete sand can help ensure consistent extrusion quality and assists in maintaining the geometry of deposited layers.Superplasticizer

[0057] The dry-mix composition further includes at least one superplasticizer. The superplasticizer is incorporated to maintain or enhance the fluidity of the mortar without requiring additional water, thereby promoting smooth pumpability and extrudability during 3D-printing operations. By enabling reduced water content, the superplasticizer also helps preserve strength development, minimize shrinkage, and maintain the dimensional stability of the printed structure upon curing.

[0058] In the context of the present dry-mix composition, the superplasticizer is provided in a dry, powder form. However, it is understood that a superplasticizer in liquid form may alternatively be used, such as at the mixing site, and combined with the remaining dry components of the dry-mix composition, together with water, to produce the printing mortar. The ability to employ either a dry or liquid superplasticizer provides flexibility in manufacturing, transportation, and on-site mixing operations without altering the intended performance of the resulting mortar.

[0059] The at least one superplasticizer may comprise a synthetic polymer acting as a water-reducing agent (or water reducer). The presence of the superplasticizer in the drymix composition enables the resulting mortar to reach a homogeneous consistency more rapidly when mixed with water, as compared to an otherwise identical mortar composition lacking the superplasticizer. This improved dispersion and faster homogenization facilitates use of the mortar in continuous mixing systems, where short mixing times are required for efficient and uninterrupted operation.

[0060] In some embodiments, the at least one superplasticizer can include at least one of a polycarboxylate-based superplasticizer, a melamine-based superplasticizer, a lignosulfonate-based superplasticizer, or any combination thereof. In a particular embodiment, the at least one superplasticizer is a polycarboxylate ether-based superplasticizer. As used herein, a polycarboxylate ether-based superplasticizer refers to a high-efficiency dispersing agent relying on steric effects to attach to the surface of binder particles, such as cement particles, and induces mutual repulsion between the particles, thereby increasing the fluidity of the dry-mix composition without the need foradditional water. In some embodiments, commercially available polycarboxylate ether-based superplasticizers may be employed.

[0061] Advantageously, the at least one superplasticizer may be provided as part of the dry-mix composition to assist in reaching an optimal flowability without requiring further addition of a large amount of water during preparation of the mortar.

[0062] In some embodiments, the presence of the superplasticizer in the dry-mix composition, in combination with the other ingredients defined herein, enables the formation of a mortar that achieves a cone penetration greater than about 50 mm and a flowability greater than about 100%, when tested in accordance with ASTM C780-23 Annex A1, and ASTM C1437-20, respectively. These performance characteristics can be obtained even when using a reduced water content, for example by adding from about 8 wt.% to about 25 wt.% of water based on the total weight of the dry-mix composition. The ability to achieve such rheological properties at lower water contents contributes to improved early-age strength, dimensional stability, and print quality.

[0063] While the superplasticizer directly influences the flowability and consistency of the mortar, viscosity-modifying agents or viscosity modifiers (described subsequently) can be used in combination with the superplasticizer to prevent segregation of raw materials and to impart the stiffness and cohesiveness necessary for layer retention. These viscosity modifiers contribute to the mortar’s ability to maintain its shape once extruded, ensuring proper interlayer adhesion and the structural stability required during the layer-by-layer deposition characteristic of additive manufacturing.Viscosity Modifier

[0064] The dry-mix composition further includes at least one viscosity modifier. The viscosity modifier may be incorporated as a part of the dry-mix composition to increase the cohesion and internal stability of the resulting mortar, which is critical for retaining the shape of each deposited layer as a structure or object is built by 3D-printing extrusion. The viscosity modifier enhances the mortar’s ability to maintain its geometry immediately after extrusion, thereby supporting proper layer retention and interlayer adhesion. In addition, the viscosity modifier may assist in retaining moisture within the prepared mortar and help reduce drying shrinkage, contributing to improved dimensional stability and overall print quality.

[0065] In some embodiments, the at least one viscosity modifier can be selected from clay, silica fume, cellulose ether, fly ash, starch ether, biopolymer gums, or any combination thereof. In some embodiments, the dry-mix composition can include two viscosity modifiers, such as clay and silica fume, which may act synergistically to enhance cohesion and shape retention during printing. In other embodiments, the dry-mix composition includes fly ash and silica fume as the viscosity-modifying system. Optionally, cellulose ether may be incorporated to further promote moisture retention.

[0066] In a particular embodiment, the at least one viscosity modifier comprises a low-viscosity cellulose ether. Such a cellulose ether can function both as a water- retaining agent and as a viscosity modifier. It may help stabilize moisture during hydration, improve cohesiveness, and reduce segregation. In 3D-printing applications, a cellulose-ether viscosity modifier can enhance print stability, particularly during pumping and extrusion, and may help the freshly deposited layers retain their geometry without slump.

[0067] In some embodiments, the at least one viscosity modifier comprises a viscosity-enhancing agent. For example, the viscosity-enhancing agent can function as a rheology modifier that increases the viscosity of the fresh mortar and stabilizes the mixture. Such an agent may help prevent segregation and bleeding, control yield stress, and enable the mortar to retain its shape immediately after deposition. In 3D-printing applications, the viscosity-enhancing agent can improve buildability, ensuring that newly deposited layers do not collapse and allowing taller structures to be printed without deformation. Any suitable viscosity-enhancing agent is contemplated.

[0068] In some embodiments, slaked lime (calcium hydroxide) of any type can be further included in the dry-mix composition in an amount of at most about 4 wt.% based on the total weight of the dry-mix composition. The presence of slaked lime can contribute to reducing pumping pressure and improving overall printability of the mortar by enhancing lubrication and aiding in the mortar’s extrudability. In some embodiments, the dry-mix composition can include at least one superplasticizer including fly ash, silica fume and slaked lime.

[0069] It is noted that certain components identified herein as superplasticizers or viscosity modifiers may also exhibit additional inherent properties, such as bindingcharacteristics, even though they are not classified as binders for the purposes of the present disclosure. For example, fly ash and slaked lime, although described above as viscosity-modifying agents, may also contribute to binding or cementitious reactions within the dry-mix composition. Such multifunctional behavior does not alter their classification herein, but may provide beneficial supplementary effects on the performance of the printing mortar.Setting Accelerator

[0070] In some embodiments, the dry-mix composition can further include at least one setting accelerator. The setting accelerator can be selected to ensure that each deposited layer of the printed structure hardens sufficiently quickly to support the weight and pressure of subsequently extruded layers. Incorporation of a suitable accelerator can improve early-age strength development, reduce the risk of deformation or collapse during printing, and enhance the overall buildability of the structure in additive manufacturing applications.

[0071] It is noted that the setting accelerator may alternatively be added to the mortar during the printing process. In such embodiments, a liquid accelerator can be delivered directly to the printhead and combined with the mortar immediately prior to extrusion. This approach can allow the accelerator to act at the precise moment of deposition, providing enhanced control over setting time and early-age strength development during 3D-printing.

[0072] For example, a setting accelerator may be used when ambient environmental conditions are insufficient to achieve an initial set time between about 90 minutes and about 180 minutes, as measured in accordance with ASTM C191. In contrast, in conditions of elevated temperature and low humidity, where the mortar naturally exhibits accelerated setting, the setting accelerator may be omitted. This flexibility allows the formulation to be adapted to varying printing environments while maintaining reliable buildability and interlayer stability.

[0073] In some embodiments, the at least one setting accelerator can be selected from calcium sulfoaluminate cement, calcium aluminate cement, calcium nitrate, calcium nitrite, calcium formate, lithium carbonate, lithium sulfate, aluminum-based compounds, or any combination thereof. The inclusion of such setting accelerators can significantlyincrease the rate of early-age hydration, thereby speeding up the curing process and reducing the time required for each printed layer to gain sufficient mechanical stability. By promoting rapid stiffening, the accelerator helps prevent sagging, deformation, or collapse of freshly deposited layers during 3D-printing operations and improves overall buildability of the multi-layered structure.Shrinkage-Reducing Additive

[0074] In some embodiments, the dry-mix composition includes at least one shrinkage-reducing additive. The shrinkage-reducing additive can help reduce drying shrinkage and associated cracking, thereby improving dimensional stability during curing. In additive-manufacturing applications, the shrinkage-reducing additive may minimize shrinkage-related stresses between printed layers, help maintain structural accuracy, and reduce the likelihood of early-age microcracking. Any compatible shrinkage-reducing additive is contemplated.

[0075] In a particular embodiment, the shrinkage-reducing additive may be hexylene-glycol-based shrinkage-reducing additive which may be supported on an inorganic carrier suitable for incorporation into dry-mix mortar formulations. Other suitable shrinkage-reducing additives may include propylene-glycol-based, polyethylene-glycol-based, alcohol-based, or surfactant-based systems. These additives may likewise be supported on an inorganic carrier to facilitate effective dispersion in dry-mix compositions.

[0076] In some embodiments, the dry-mix composition includes between about 0 wt.% and about 1.5 wt.% of the at least one shrinkage-reducing additive, based on the total weight of the dry-mix composition. For example, the shrinkage-reducing additive may be present in an amount between about 0.1 wt.% and about 1.2 wt.%, or between about 0.2 wt.% and about 1.0 wt.%, depending on the desired degree of dimensional stability and the specific performance requirements of the additive-manufactured structure.Superabsorbent Polymer

[0077] In some embodiments, the dry-mix composition can include at least one superabsorbent polymer. When present, the superabsorbent polymer may facilitate moisture retention within the mortar during the hydration process, thereby promotingself-curing. The presence of the superabsorbent polymer can help maintain internal humidity, reduce drying shrinkage, and improve early-age stability of the printed layers, particularly in environments where external curing conditions may be insufficient.Polymeric Performance Additive

[0078] In some embodiments, the dry-mix composition can include at least one polymeric performance additive selected, for example, to enhances cohesion, adhesion, flexibility, and interlayer bonding in the mortar. Any compatible polymeric performance additive is contemplated.

[0079] In a particular embodiment, the at least one polymeric performance additive characterized herein as a formaldehyde-free redispersible polymer powder (RPP) functioning as a polymeric performance additive. When incorporated into the dry-mix composition, the polymer powder can improve cohesion, flexibility, and toughness of the mortar, and can enhance bonding strength both within individual layers and between successively printed layers during additive manufacturing. The polymer powder may also contribute to improved crack resistance, reduced brittleness, and enhanced durability of the hardened structure. In some embodiments, the redispersible polymer powder may promote superior interlayer adhesion, which may be advantageous for multi-layer deposition in 3D-printing processes.Pigment

[0080] In some embodiments, the dry-mix composition can include at least one pigment. The pigment may be incorporated to provide aesthetic flexibility during the construction process, enabling the formation of custom-colored walls and structures directly through the printing operation, without the need for additional finishing or coating layers. The inclusion of pigment can also facilitate visual differentiation of printed components or layers, if desired.

[0081] In some embodiments, the at least one pigment can be selected from ferric oxides of any shade, titania, calcium carbonate, or any other commercially available pigments suitable for use in cement- or mortar-based systems. The pigment may be included alone or in combination with other pigments to achieve a desired color tone or opacity.Fibers

[0082] In some embodiments, the dry-mix composition further can include fibers to enhance crack resistance, particularly in applications involving exceptionally large structures (e.g., structures having any dimension greater than about 40 ft). The fibers may have a length ranging from about 1 / 4 inch (about 6 mm) to about 1 inch (about 25 mm). Suitable fibers include, without limitation, inorganic fibers such as glass fibers or steel fibers, as well as organic fibers (e.g., polymeric or natural-origin fibers). The incorporation of such fibers can improve tensile toughness, mitigate crack propagation, and provide additional structural resiliency under load or environmental stress.Environmentally Beneficial Additive

[0083] Depending on performance and sustainability requirements, the dry-mix composition can be formulated to yield a mortar that reduces its associated carbon footprint, water footprint, or both, and / or incorporates recycled or waste-derived materials. Tailoring of the dry-mix composition can be achieved by partially or fully substituting conventional constituents with environmentally beneficial alternatives while maintaining acceptable mechanical and durability performance.

[0084] In some embodiments, the dry-mix composition can further include at least one environmentally beneficial additive, which may be incorporated at any dosage that provides satisfactory strength, durability, workability, or other performance criteria relevant to the intended application. The selection and proportion of such additives can be adjusted according to structural requirements, curing conditions, or sustainability targets.

[0085] By way of example, the at least one environmentally beneficial additive can be selected from slags (e.g., ground-granulated blast-furnace slag), fly ashes, other pozzolanic materials (either naturally occurring or synthetically produced), waste glass (finely ground or otherwise processed), plastics (raw, recycled, or mechanically processed), calcined clays, or any combination thereof. These materials can contribute to reduced embodied carbon, improved circularity through incorporation of waste streams, and enhanced long-term performance characteristics of the resulting mortar.

[0086] In some embodiments, the at least one environmentally beneficial additive comprises a fine mineral filler that may also function as a pozzolanic and / or rheological additive. Such materials can improve the workability and print performance of the 3D-printing mortar, including better handling during mixing, pumping, and deposition. They may further increase durability of the printed material and enhance fresh-state behavior (rheology) to support stable layer deposition and buildability. In some embodiments, the fine mineral filler may mitigate deleterious reactions or attacks, including reducing susceptibility to alkali-silica reaction (ASR)-related distress and improving resistance to chemical exposure or sulfate attack. In some embodiments, kaolin is present in the dry-mix composition in an amount in the range of about 0 wt.% to about 6 wt.%, based on the total weight of the dry-mix composition. For example, the kaolin may be present in an amount between about 1 wt.% and about 5 wt.%, or between about 2 wt.% and about 4 wt.%, depending on the desired rheological or durability benefits. In a particular embodiment, Kaolin is present in the dry-mix composition in an amount in the range of about 1 wt.% to about 2 wt.%, based on the total weight of the dry-mix composition.Surface Treatment Additive

[0087] The dry-mix composition can further be tailored to exhibit enhanced durability when the cured structure is exposed to challenging indoor or outdoor environments, including those involving frequent or prolonged contact with water, de-icing salts, acidic or alkaline substances, or other chemically aggressive agents. In some embodiments, the dry-mix composition includes at least one surface-treatment additive that improves resistance to moisture ingress, chemical attack, staining, or surface degradation, thereby extending the service life of the resulting structure.

[0088] In some embodiments, the dry-mix composition can include at least one surface-treatment additive. For example, the dry-mix composition can contain a waterproofing agent or a sealant comprising a hydrophobic chemical additive. Suitable hydrophobic agents include, without limitation, calcium stearate, silanes, siloxanes, and combinations thereof. The incorporation of such waterproofing agents can enhance resistance to water penetration and chemical attack, and may additionally improve the stability and workability of the mortar during extrusion or deposition in additive-manufacturing (printing) processes.Mortar

[0089] The mortar is formed by combining the dry-mix composition with water, thereby initiating the hydration reactions that lead to curing and development of a hardened structure. Any suitable water source may be used, including potable water, provided that the dissolved constituents or impurities present in the water do not adversely affect the hydration process, workability, setting behavior, or mechanical properties of the resulting mortar.

[0090] The mortar comprises the dry-mix composition and water, the water being present in an amount ranging from about 8 wt.% to about 25 wt.% relative to the total weight of the dry-mix composition. Exemplary intermediary ranges include from about 10 wt.% to about 22 wt.%, from about 12 wt.% to about 20 wt.%, or from about 13 wt.% to about 19 wt.% of water relative to the total weight of the dry-mix composition. In a particular embodiment, the water is present in an amount between 14 wt.% and 18 wt.% relative to the total weight of the dry-mix composition. These ranges can be selected to provide suitable workability, print stability, hydration control, and mechanical performance of the hardened structure.

[0091] In some embodiments, the weight ratio of water to binder can range up to about 0.4 to about 0.7. In some other embodiments, the weight ratio of water to binder can range up to about 0.5 to about 1.0. Selection of a suitable water-to-binder ratio can depend on the desired workability, rheology, extrusion behavior, and ultimate strength development of the mortar.

[0092] In some embodiments, the mortar has an initial set time between about 90 minutes and about 180 minutes when tested in accordance with ASTM C191. Such a setting profile can provide sufficient open time for mixing, conveying, and layer deposition while ensuring timely strength development for subsequent structural support.

[0093] In some embodiments, the mortar exhibits a cone penetration between about 50 mm and about 80 mm, measured in accordance with ASTM C780-23 Annex A1, at approximately 5 minutes after mixing the dry-mix composition with water. In a particular embodiment, the cone penetration is between 60 mm and 70 mm at the same measurement time. Such penetration values can correspond to suitable early-age workability and rheology for consistent extrusion or placement.

[0094] In some embodiments, the mortar exhibits a flowability between about 80% and about 140%, as measured in accordance with ASTM C1437 (or ASTM C1437-20). Exemplary intermediary ranges include from about 85% to about 130%, from about 90% to about 125%, or from about 95% to about 120%. In particular embodiment, the flowability is between about 100% and about 110%. Such flowability ranges can correspond to suitable workability, spreadability, and consistency for controlled placement or extrusion.

[0095] In some embodiments, the mortar has a 24-hour compressive strength greater than about 1,500 psi and a 28-day compressive strength greater than about 5,000 psi, as measured in accordance with ASTM C109. Such early-age and long-term strength values can provide adequate load-bearing capacity for structural applications and support layer-by-layer construction processes.Exemplary Dry-Mix Composition

[0096] An exemplary dry-mix composition is presented in Table 2 below.Table 2 - Exemplary Dry-Mix CompositionProcess / Method Features

[0097] There is provided a method for preparing the mortar, the method including mixing the dry-mix composition comprising the filler, binder, superplasticizer, and viscosity modifier with water to produce a homogeneous mixture, thereby ensuring consistent texture and predictable behavior during subsequent printing of the mortar. In some embodiments, at least one of the setting accelerator, superabsorbent polymer, pigment, environmentally beneficial additive, or surface-treatment additive, as defined herein, is added before, during, or after the addition of water to the dry-mix composition, provided that such addition occurs prior to or during mixing to form the homogeneous mixture. In some embodiments, the mixing step includes first forming the dry-mix composition by combining the filler, binder, superplasticizer, and viscosity modifier, and subsequently contacting the resulting dry mixture with water to obtain the homogeneous mortar mixture.

[0098] In some embodiments, the mixing can be performed for a duration between about 1 minute and about 5 minutes. In some embodiments, the mixing is performed at a temperature between about 10 °C and about 33 °C. Optionally, the mixing can be carried out in either a continuous mixer or a batch mixer, depending on the operational requirements and the intended mode of application.

[0099] In some embodiments, water can be present in an amount between about 8 wt.% and about 25 wt.% relative to the total weight of the dry-mix composition. Exemplary intermediary ranges include from about 10 wt.% to about 22 wt.%, from about 12 wt.% to about 20 wt.%, or from about 13 wt.% to about 19 wt.% of water relative to the total weight of the dry-mix composition. In a particular embodiment, the water is present in an amount between about 14 wt.% and about 18 wt.% relative to the total weight of the dry-mix composition.

[0100] The proportions of the dry-mix ingredients, including the filler, binder, superplasticizer, and viscosity modifier, can be tailored to meet the requirements of additive-manufacturing applications. The dry-mix composition as described herein is formulated to produce a mortar exhibiting suitable flowability for reliable printability and layer stability during deposition, while also achieving the desired strength upon curing to form a structural element. By appropriately balancing these components, an automated, precise, and efficient construction process can be achieved.

[0101] The dry-mix composition can be designed to include a greater proportion of filler (e.g., fine aggregates) relative to binder. In some embodiments, the weight ratio of filler to binder is between about 1.5 and about 2.5. Such proportions can contribute to desirable rheology, printability, buildability, and cost efficiency while maintaining adequate mechanical performance in the cured structure.

[0102] In some embodiments, the superplasticizer can be present in an amount between about 0.2 wt.% and about 1 wt.%, relative to the total weight of the dry-mix composition. In some embodiments, the superplasticizer can be present in an amount between about 0.5 wt.% and about 1 wt.%. Such dosages can improve workability, dispersion, and flowability while maintaining the required buildability for additive-manufacturing applications.

[0103] In some embodiments, the viscosity modifier can be present in an amount between about 1 wt.% and about 15 wt.% relative to the total weight of the dry-mix composition. Exemplary intermediary ranges include from about 2 wt.% to about 12 wt.%, from about 3 wt.% to about 11 wt.%, or from about 4 wt.% to about 10 wt.%. In a particular embodiment, the viscosity modifier can be present in an amount between about 3 wt.% and about 10 wt.%. Such amounts can be selected to provide suitable rheology, buildability, and shape retention during additive-manufacturing operations.

[0104] For example, a flow table conforming to ASTM C1437 and a modified ASTM C780 Vicat Cone penetrometer can be employed to adjust the dosage of the viscosity modifier and / or superplasticizer so as to achieve the desired consistency of the mortar. During a development period, tests can be conducted at approximately 5 minutes after mixing and again at approximately 25 minutes after mixing to ensure that the mortar meets the required flow and cone penetration criteria within the specified time window.

[0105] There is also provided a process for building a multi-layered structure by additive manufacturing using the dry-mix composition as defined herein. The process comprises providing the dry-mix composition, combining the dry-mix composition with water to form a mortar, and printing at least one layer of the mortar in accordance with predetermined building instructions. In some embodiments, the printing step includes extruding the mortar using a 3D printer to form the at least one layer.

[0106] In some embodiments, the process further includes printing a subsequent layer onto the at least one previously printed layer. The printing speed can be adjusted such that the previously deposited layer is allowed to undergo between about 8 minutes and about 25 minutes of curing time prior to deposition of the subsequent layer. The printing speed is thereby tailored to allow each layer to reach a thumbprint-hard condition before the next layer is printed, ensuring adequate buildability and interlayer adhesion during the additive-manufacturing process.

[0107] In some embodiments, the process for building the structure by additive manufacturing includes preparing the dry-mix composition and the corresponding mortar according to the methods and proportions defined herein. The workability of the mortar prior to printing can be maintained by continued mixing or agitation. In some embodiments, the printing can be carried out within at most about 30 minutes from the time the water is added to the dry-mix composition to form the mortar, thereby ensuring suitable consistency and print performance during deposition.

[0108] In some embodiments, the printing of each layer is performed at a temperature between about 10 °C and about 33 °C. Exemplary intermediate ranges include from about 12 °C to about 30 °C, from about 15 °C to about 28 °C, or from about 18 °C to about 26 °C. Such a temperature range can help maintain suitable workability, consistency, and curing behavior of the mortar during the additive-manufacturing process.

[0109] Optionally, the process for building the structure can further include applying the curing agent, as defined herein, onto the surface of the printed multi-layer structure to reduce evaporation and minimize surface cracking after printing. In some embodiments, the multi-layer structure resulting from curing of the mortar is sealed with the curing agent, such as a wax-based material or an acrylic resin (e.g., Sakrete® Cure 'n Seal).

[0110] The present additive-manufacturing cementitious composition can be optimized to provide both printability and structural performance. The present technology plays a pivotal role in advancing automated, cost-effective, and sustainable construction techniques. By utilizing this composition, construction efficiency can be increased while reducing labor requirements and material waste, enabling the creation ofcustom-designed structures with shorter project timelines and improved environmental sustainability.

[0111] There is also provided the use of a dry-mix composition as defined herein for the production of a multi-layered structure by additive manufacturing. For example, the dry-mix composition can be used for producing a structural foundation of a house by additive manufacturing, and more particularly by 3D-printing.

[0112] There is further provided a multi-layered structure produced by additive manufacturing of layers of the mortar as defined herein, the mortar being formed upon adding water to the dry-mix composition as described herein.EXAMPLES

[0113] The following non-limiting examples are illustrative embodiments and should not be construed as further limiting the scope of the present invention.

[0114] Experimental testing was performed to evaluate fresh-state properties, mechanical performance, dimensional stability, bond performance, stiffness characteristics, and freeze-thaw durability of a 3D-printable cementitious mortar composition suitable for additive manufacturing applications.

[0115] Mixing procedures and preparation of test specimens were conducted under controlled laboratory conditions. Unless otherwise indicated, testing was performed in substantial accordance with the referenced standards. Any modifications to standardized procedures are expressly noted below.Compressive Strength

[0116] Compressive strength of hydraulic cement mortars was determined in substantial accordance with ASTM C109-21 (Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens)).

[0117] Mortar mixtures were prepared using the dry-mix composition as described herein and water at the proportions set forth in Table 3. Mixing was performed in a laboratory pan mixer for approximately three (3) minutes. The mortar was cast into 50mm (2 inch) cube molds in two layers with consolidation after each layer. The top surface was struck flush with the mold.

[0118] Specimens were moist cured, demolded after approximately 24 hours, and subsequently stored in a controlled moist curing environment until testing at 1 , 7, and 28 days. Compressive strength was calculated as the maximum applied load divided by the loaded cross-sectional area (4.00 in2). Reported values represent the average of three specimens.Flexural Strength (Modulus of Rupture)

[0119] Flexural strength was determined in substantial accordance with ASTM C78-22 (Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)).

[0120] Mortar beam specimens measuring approximately 2 in. x 2 in. x 6 in. were prepared from the cementitious composition as described herein and consolidated to minimize entrapped air. Following moist curing to the designated test ages (1, 7, and 28 days), each beam was placed on simple supports within a flexural testing apparatus.

[0121] Load was applied at the third points of the span to establish a substantially constant bending moment between the loading points. Loading was applied at a controlled rate and continued until rupture occurred. The modulus of rupture was calculated from the maximum applied load, support span, and specimen dimensions in accordance with the relationships set forth in the referenced standard. Reported values represent the average of three replicate specimens.Density, Yield, and Gravimetric Air Content

[0122] Fresh mortar density (unit weight) and gravimetric air content were determined using procedures substantially similar to ASTM C138-17 (Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete), adapted for mortar mixtures.

[0123] Fresh mortar was placed into a calibrated measure in layers with consolidation by rodding. The surface was struck off flush and the filled measure was weighed. Density was calculated from the net mass divided by the known volume of the measure.Gravimetric air content was calculated from measured density and theoretical mixture density.Length Change (Shrinkage / Expansion)

[0124] Length change of hardened mortar specimens was determined in substantial accordance with ASTM 0157-17 (Standard Test for Length Change of Hardened Hydraulic-Cement Mortar and Concrete).

[0125] Prismatic specimens incorporating embedded gauge studs were cast and moist cured for an initial period. An initial comparator reading was obtained following demolding. Specimens were thereafter stored either in air (approximately 50% relative humidity) or in water. Periodic comparator measurements were taken, and length change was expressed as a percentage relative to the initial gauge length. Reported values represent averages of three specimens.Slant-Shear Bond Strength (Modified)

[0126] Bond strength was determined using a modified procedure based on ASTM C882-20 (Standard Test Method for Bond Strength of Epoxy-Resin Systems Used with Concrete by Slant Shear).

[0127] In the present testing, both the hardened substrate and the freshly placed overlay were prepared from the cementitious mortar composition as described herein rather than from an epoxy bonding system. Hardened substrate specimens were surface conditioned prior to casting fresh mortar against the prepared surface to form composite slant-shear specimens. After curing to 28 days, specimens were loaded in compression to induce shear stress along the bonded interface. Bond strength was calculated as the maximum load divided by the bonded area. Reported values represent averages of three specimens.Mortar Flow

[0128] Workability of mortar mixtures was evaluated in substantial accordance with ASTM C1437-20 (Standard Test Method for Flow of Hydraulic Cement Mortar).

[0129] Fresh mortar was placed into a truncated conical mold centered on a flow table. The mold was lifted vertically, and the table was dropped the prescribed number of times within the specified interval. The spread diameter was measured along perpendicular directions and expressed as a percentage increase relative to the original base diameter.Dynamic Modulus of Elasticity

[0130] Dynamic modulus of elasticity was determined in substantial accordance with ASTM C215-19 (Standard Test Method for Fundamental Transverse, Longitudinal, and Torsional Resonant Frequencies of Concrete Specimens).

[0131] Hardened mortar prisms were supported at nodal points and mechanically excited to induce vibration. The fundamental resonant frequency was measured and used to calculate dynamic modulus of elasticity based on specimen mass and geometry. Reported values represent averages of three specimens.Slow Freezing and Thawing in Brine

[0132] Freeze-thaw durability was evaluated in substantial accordance with PA Test Method No. 633 (Measuring the Resistance of 50 mm x 50mm (2” x 2”) Cube Specimens of Mortar to Slow Freezing and Thawing in Brine).

[0133] Mortar cube specimens were subjected to repeated freezing and thawing cycles in a brine solution. At designated cycle intervals, specimens were removed, surface dried, and weighed. Percent weight loss was calculated relative to initial specimen mass. Average weight loss after 25 cycles is reported.Experimental Conditions

[0134] The mix proportions and laboratory conditions used for testing are presented in Table 3.Table 3 - Mix Proportions and Laboratory Conditions

[0135] Individual test results are provided in Table 4 through Table 11. A photograph of representative test samples upon completion of PA Test Method No. 633 is shown in Figure 1. For purposes of ASTM C882 testing, the standard procedure was modified such that both the hardened substrate and the freshly mixed substrate were produced using the supplied dry-mix composition.

[0136] The experimental data presented in Tables 4-11 demonstrate that the disclosed mortar composition exhibits high early and later-age compressive strength, enhanced flexural performance, controlled dimensional stability, strong interfacial bond strength, adequate workability for additive manufacturing, high dynamic modulus, and negligible mass loss after 25 freeze-thaw cycles in brine.Table 4 - Summary of Test Results for 3D-Printed MortarTable 5 - ASTM C109 Test Results for 3D-Printed MortarTable 6 - ASTM C78 Flexural Strength Results for 3D-Printed MortarTable 7 - ASTM C882 Modified Slant-Shear Bond Strength for 3D-Printed MortarTable 8 - ASTM C157 Test Results (Air Cured) for 3D-Printed MortarTable 9 - ASTM C157 Test Results (Water Cured) for 3D-Printed MortarTable 10 - ASTM C215 Test Results for 3D-Printed MortarTable 11- PA Test Method No. 633 Freeze / Thaw Test Results for 3D-Printed Mortar

[0137] Several alternative embodiments and examples have been described herein. The embodiments of the invention described above are intended to be exemplary only. A person of ordinary skill in the art will appreciate the features of the individual embodiments, as well as the possible combinations and variations thereof. A person of ordinary skill in the art will further recognize that any of the embodiments disclosed herein may be combined with any other embodiment unless such combinations are mutually exclusive. The invention may be embodied in other specific forms without departing from its essential characteristics. Accordingly, the present examples andembodiments are to be considered as illustrative and not restrictive, and the scope of the invention is intended to be defined solely by the appended claims.

[0138] It should be understood that any one of the optional or exemplary aspects of each process, method, or composition described herein may be combined with any other aspect unless two aspects are clearly incompatible due to mutual exclusivity.

Claims

CLAIMS1. A dry-mix composition for additive manufacturing, the dry-mix composition comprising:at least one binder comprising a cementitious binder;at least one filler comprising fine aggregates;at least one superplasticizer; andat least one viscosity modifier.

2. The dry-mix composition of claim 1, wherein the cementitious binder of the drymix composition is cement.

3. The dry-mix composition of claim 1 or 2, wherein the cementitious binder is selected from Type I cement, Type II cement, Type III cement, Type IV cement, Type V cement, Type IL cement, and Type IP cement.

4. The dry-mix composition of any one of claims 1 to 3, wherein the cementitious binder is a primary binder and the dry-mix composition further comprises a secondary binder.

5. The dry-mix composition of any one of claims 1 to 4, wherein the fine aggregates have a particle size distribution in substantial accordance with ASTM C33 / C33M-23 for fine aggregates.

6. The dry-mix composition of any one of claims 1 to 5, wherein the fine aggregates comprise or consist of sand.

7. The dry-mix composition of any one of claims 1 to 6, wherein the at least one filler comprises the fine aggregates and at least one additional filler.

8. The dry-mix composition of claim 7, wherein the additional filler is selected from ground calcium carbonate, silica fume, perlite, expanded shale, pumice, plastic aggregates, organic aggregates, recycled concrete aggregates, and any combination thereof.

9. The dry-mix composition of any one of claims 1 to 8, wherein the at least one superplasticizer comprises a synthetic polymer.

10. The dry-mix composition of any one of claims 1 to 9, wherein the at least one superplasticizer comprises a polycarboxylate-ether-based superplasticizer.

11. The dry-mix composition of any one of claims 1 to 10, wherein the at least one viscosity modifier comprises clay, silica fume, cellulose ether, fly ash, starch ether, biopolymer gums, slaked lime, or any combination thereof.

12. The dry-mix composition of any one of claims 1 to 11, further comprising at least one setting accelerator.

13. The dry-mix composition of claim 12, wherein the at least one setting accelerator is selected from calcium sulfoaluminate cement, calcium aluminate cement, calcium nitrate, calcium nitrite, calcium formate, lithium carbonate, lithium sulfate, aluminum-based compounds, and any combination thereof.

14. The dry-mix composition of any one of claims 1 to 13, further comprising at least one hydrophobic chemical agent.

15. The dry-mix composition of claim 14, wherein the hydrophobic chemical agent is selected from calcium stearate, silanes, siloxanes, and any combination thereof.

16. The dry-mix composition of any one of claims 1 to 15, further comprising at least one of a superabsorbent polymer, a pigment, fibers, or an environmentally beneficial additive.

17. The dry-mix composition of any one of claims 1 to 16, wherein a weight ratio of the at least one filler to the at least one binder is between about 1.5 and about 2.5.

18. The dry-mix composition of any one of claims 1 to 17, wherein the at least one superplasticizer is present in an amount between about 0.2 wt.% and about 1 wt.% relative to the total weight of the dry-mix composition.

19. The dry-mix composition of any one of claims 1 to 18, wherein the at least one viscosity modifier is present in an amount between about 1 wt.% and about 15 wt.% relative to the total weight of the dry-mix composition.

20. A mortar comprising water and the dry-mix composition as defined in any one of claims 1 to 19, wherein the water is present in an amount between about 8 wt.% and about 25 wt.% relative to the total weight of the dry-mix composition.

21. The mortar of claim 20, wherein the water is present in an amount between about 14 wt.% and about 18 wt.% relative to the total weight of the dry-mix composition.

22. The mortar of claim 20 and 21, wherein a weight ratio of water to binder is between about 0.4 and about 0.7.

23. The mortar of any one of claims 20 to 22, having a flowability between about 80% and about 140% as measured by ASTM C1437.

24. The mortar of any one of claims 20 to 23, having a cone penetration between about 50 mm and about 80 mm as measured in accordance with ASTM C780-23 Annex A1 at about 5 minutes after mixing the water and the dry-mix composition.

25. The mortar of any one of claims 20 to 24, having a 24-hour compressive strength greater than about 1,500 psi and a 28-day compressive strength greater than about 5,000 psi, as measured in accordance with ASTM C109.

26. Use of the dry-mix composition of any one of claims 1 to 19 for producing a multi-layered structure by additive manufacturing.

27. A multi-layered structure produced by additive manufacturing of layers of the mortar as defined in any one of claims 20 to 25.

28. A process for producing a mortar for additive manufacturing of multi-layered structures, the process comprising mixing water with the dry-mix composition as defined in any one of claims 1 to 19, wherein water is mixed with the dry-mix composition in an amount between about 8 wt.% and about 25 wt.% relative to the total weight of the dry-mix composition.

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