Aerated concrete block masonry mortar, preparation method and application

Abstract

The invention discloses aerated concrete block masonry mortar, a preparation method and application, and relates to the field of building materials.The mortar is prepared from ordinary Portland cement, superfine sand, nano silicon dioxide, hydroxypropyl methyl cellulose ether, redispersible latex powder and modified bentonite through dry and wet mixing, dynamic water cement ratio adjusting and screening technologies. The water-retaining property is obviously improved; the shrinkage rate is reduced. A layered pouring process is adopted for the matched gradient density building block, an outer high-density layer and an inner low-density layer are compacted through vibration to form a transition layer, and a self-healing interface layer containing bacillus pasteurii is sprayed on the surface, so that microcrack repairing and durability strengthening are achieved. During construction, mortar joints are monitored in real time through infrared scanning, the mortar pump is linked to adjust the flow, and the assembling efficiency and the anti-seismic performance are improved through the prefabricated constructional column modules and the flexible connecting nodes.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and in particular to an aerated concrete block masonry mortar, a preparation method and an application thereof. Background Art

[0002] In the traditional aerated concrete masonry process, ordinary masonry mortar and homogeneous blocks are generally used in combination for construction. In the existing technology, mortar mostly relies on a single water-retaining agent (such as hydroxypropyl methylcellulose ether) or polymer (such as latex powder) to improve its performance, but the synergistic effect of the two is insufficient, resulting in the mortar's water retention (usually <85%) and shrinkage resistance being difficult to balance. After masonry, the mortar is prone to cracking due to water loss and shrinkage. The measured 28-day shrinkage rate is generally ≥0.15%, and the bonding strength is lower than 0.2MPa, which is difficult to meet the construction requirements under the high water absorption characteristics of aerated concrete. In addition, conventional homogeneous blocks (density 500-700kg / m 3 ) Due to the single-density design, there is an irreconcilable contradiction between thermal insulation performance and compressive strength (compressive strength ≤3.5MPa when thermal conductivity coefficient ≥0.16W / (m·K)), and there is a lack of active repair mechanism. After the microcracks expand, the overall deterioration of the masonry is accelerated.

[0003] At the construction level, existing technology relies on manual experience to control mortar joint thickness (error ±5mm) and fullness (qualification rate ≤85%), resulting in uneven load distribution within the masonry. Structural columns are cast in place, requiring formwork, reinforcement, and staged pouring. A single-layer construction cycle can take over 48 hours, and rigid connection nodes struggle to release thermal stress. The crack incidence rate in earthquake simulations exceeds 60%. These deficiencies collectively lead to frequent cracking, leakage, and high energy consumption within aerated concrete masonry, restricting its application in high-rise buildings and locations with high seismic requirements. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an aerated concrete block masonry mortar, a preparation method, and an application to solve one or more problems in the prior art.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] An aerated concrete block masonry mortar comprises the following components by weight:

[0007] Ordinary Portland cement 45-55%;

[0008] Extra fine sand 30-40%, fineness modulus 1.6-2.0;

[0009] Nano-silicon dioxide 1.5-2.5%, particle size 20-50nm;

[0010] Hydroxypropyl methylcellulose ether 0.15-0.25%;

[0011] Redispersible latex powder 1.2-1.8%;

[0012] 2-3% of a water retention enhancer, wherein the water retention enhancer is modified bentonite.

[0013] Furthermore, the specific surface area of the nano-silicon dioxide is 200-300m 2 / g.

[0014] In order to make the technical effect complete, the second set of technical solutions prepared by the present invention is: a method for preparing aerated concrete block masonry mortar, comprising the following steps:

[0015] Put ordinary Portland cement, extra fine sand and nano-silica into a double-shaft zero-gravity mixer and dry mix at a speed of 300-400 r / min for 5 minutes;

[0016] Add hydroxypropyl methylcellulose ether, redispersible latex powder, and water retention enhancer, switch to a speed of 200 r / min and wet mix for 8 minutes. The mixing temperature should be ≤40°C.

[0017] Dynamically adjust the water-cement ratio to 0.16-0.18 according to the moisture content of the ultra-fine sand;

[0018] The mixture is sieved through a 0.6mm aperture vibrating screen and then sealed and packaged.

[0019] Furthermore, the wet mixing stage also includes adding 0.1-0.3% of a defoaming agent.

[0020] The third technical solution of the present invention is: an application of aerated concrete block masonry mortar, which complements and nests with the first two technical solutions, including

[0021] aerated concrete block masonry mortar;

[0022] Gradient density blocks, outer density 700kg / m 3 , inner layer density 500kg / m 3 , the density gradient change rate of the transition layer is ≤10% / mm;

[0023] The self-healing interface layer is sprayed on the surface of the block, containing Bacillus pasteurianus liquid (concentration 1×10 6 CFU / mL) and silica sol in a volume ratio of 1:3.

[0024] Furthermore, the self-healing interface layer spraying process includes:

[0025] High-pressure airless spraying pressure 20-25MPa, coating thickness 80-120μm;

[0026] The shell thickness of the pH-responsive microcapsule is 50-100 μm, and the critical pH is 9.0.

[0027] Furthermore, the production of the gradient density building blocks includes:

[0028] The aluminum powder content of the outer layer aerated concrete slurry is 0.08-0.12%, and the pre-curing temperature is 50°C;

[0029] The aluminum powder content of the inner layer is 0.15-0.18%, the vibration table frequency is 50Hz, and the amplitude is 0.5mm.

[0030] Furthermore, during construction, an infrared scanner (wavelength 850nm) is used to detect the mortar joint thickness of 15±2mm and the fullness ≥90% in real time; when the mortar joint thickness exceeds the tolerance, the mortar pump PID adjustment is triggered, and the flow rate is adjustable from 0-10L / min; prefabricated structural column modules (height 600mm, tie bar groove width 6mm, depth 50mm) are installed, and C30 self-compacting concrete (slump 220±20mm) is poured.

[0031] Furthermore, the prefabricated structural column module is 3D printed using glass fiber reinforced gypsum, and has a compressive strength of ≥25MPa.

[0032] Furthermore, a neoprene gasket (Shore hardness 50±5, thickness 3mm) is provided between the structural column and the masonry, with a pre-tightening force of 0.3-0.5MPa.

[0033] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0034] (1) The synergistic strengthening effect of mortar is achieved through the combination of nano-silica (1.5-2.5%), hydroxypropyl methylcellulose ether (0.15-0.25%) and redispersible latex powder (1.2-1.8%). Nano-silica improves density by filling micropores and accelerating hydration reaction, cellulose ether ensures water retention to avoid bonding failure caused by water absorption of masonry blocks, and latex powder forms a flexible film to compensate for shrinkage stress. The synergistic effect of the three increases the 28-day compressive strength of the mortar to ≥12MPa, reduces the shrinkage rate to 0.04% (traditional mortar is 0.15%), and at the same time increases the bonding strength by more than 30%, solving the industry problem of easy cracking of aerated concrete masonry.

[0035] (2) Through gradient density blocks (outer layer 700kg / m 3 、Inner layer 500kg / m 3The combination of a self-healing interface layer (Bacillus pasteurianus liquid + silica sol) achieves complementary performance. While maintaining the compressive strength of the outer layer (≥5MPa), the gradient structure reduces the thermal conductivity of the inner layer to 0.11W / (m·K), a 31% improvement in thermal insulation compared to homogeneous blocks (0.16W / (m·K)). The self-healing interface layer actively repairs microcracks ≤0.3mm through microbial metabolism, maintaining a repair rate of ≥80% after 50 freeze-thaw cycles, providing a dual guarantee for the mechanical properties and durability of the blocks.

[0036] (3) A digital construction system was established through the combined application of infrared real-time mortar joint monitoring (accuracy ±0.3mm) and prefabricated structural column modules (3D-printed glass fiber reinforced gypsum). Infrared scanning automatically detects mortar joint thickness (15±2mm) and fullness (≥90%) after every three bricks are laid. This is coupled with PID control of the mortar pump, increasing the mortar joint pass rate from 85% with traditional manual methods to 98%. The prefabricated modules are designed with tie bar notches, and combined with the pouring of self-compacting concrete (slump 220±20mm), the single-layer construction period has been shortened from 2 days to 0.5 days, achieving simultaneous breakthroughs in quality and efficiency.

[0037] (4) A dynamic stress release mechanism is created through the coordinated design of flexible connection nodes (neoprene rubber gaskets, Shore hardness 50±5) and gradient block transition layers (density gradient change rate ≤10% / mm). The rubber gaskets allow ±2mm displacement to absorb thermal deformation, and the transition layer prevents interfacial delamination caused by sudden density changes. The combined effect of these two factors reduces the crack incidence of the masonry by 60-80% in earthquake simulation tests, without the need for additional seismic structural measures, significantly reducing overall construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a preparation flow chart of aerated concrete block mortar in the present invention.

[0039] Figure 2 It is a construction flow chart for the application of aerated concrete block mortar in the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and exemplary explanations. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not intended to limit the conditions for the implementation of the present invention. Therefore, they have no technical significance. Any modification of the structure, change in the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose of the present invention.

[0041] Application Overview

[0042] At present, the field of aerated concrete masonry generally adopts ordinary silicate mortar and homogeneous blocks for construction, but the existing technology has significant limitations. Conventional mortar relies on a single water-retaining agent or polymer modification, resulting in insufficient water retention (water retention rate <90%) and high shrinkage rate (28-day shrinkage rate ≥0.15%). It is difficult to adapt to the high water absorption characteristics of aerated concrete, and it is easy to cause cracking of mortar joints and bond failure. At the same time, homogeneous blocks are designed with a single density, which cannot take into account both compressive strength and thermal insulation performance, and lack self-repairing ability after micro-cracks expand, which accelerates the deterioration of masonry structures. In the construction process, the quality control of mortar joints relies on manual experience, with large errors (thickness deviation ±5mm) and low pass rate (≤85%). The process of casting structural columns is cumbersome (single-layer construction period >48 hours), and rigid connection nodes are prone to cracking due to stress concentration.

[0043] This solution breaks through the above-mentioned technical bottlenecks through multi-dimensional collaborative innovation. Nano-silica and polymer composite modified mortar is used to improve water retention (≥95%) and reduce shrinkage (≤0.04%); gradient density blocks are designed in combination with a microbial self-healing interface layer to achieve synergistic optimization of strength and thermal insulation performance (thermal conductivity ≤0.11W / (m·K), compressive strength ≥5MPa); infrared intelligent monitoring and modular installation of prefabricated structural columns are introduced to increase the mortar seam qualification rate to ≥98%, and construction efficiency is increased by more than 3 times. The flexible connection node design further releases stress, significantly reduces the crack incidence (<20%), and comprehensively solves the core problems of traditional processes such as cracking, inefficiency, and high energy consumption.

[0044] Comprehensive description

[0045] 1. Masonry mortar formula and preparation

[0046] The aerated concrete block masonry mortar provided by the present invention comprises the following components (by weight percentage):

[0047] Cementitious material: ordinary Portland cement (PO 42.5 grade) 45% to 55%;

[0048] Aggregate: extra fine sand (fineness modulus 1.6-2.0, mud content ≤1.5%) 30%-40%;

[0049] Reinforcement agent: nano-silicon dioxide (particle size 20-50nm, specific surface area 200-300m 2 / g) 1.5% to 2.5%;

[0050] Water-retaining agent: hydroxypropyl methylcellulose ether (HPMC, viscosity 40000mPa·s) 0.15% to 0.25%;

[0051] Polymer modifier: redispersible latex powder (ethylene-vinyl acetate copolymer, glass transition temperature -5°C) 1.2% to 1.8%;

[0052] Auxiliary water-retaining agent: modified bentonite (cation exchange capacity ≥ 70mmol / 100g) 2% to 3%.

[0053] The steps for preparing mortar are as follows:

[0054] Dry mixing stage: Cement, ultrafine sand and nano-silica are placed in a dual-shaft zero-gravity mixer and mixed at 300-400 rpm for 5 minutes to ensure uniform dispersion of the nanoparticles.

[0055] Wet mixing stage: Add HPMC, latex powder, bentonite and defoamer (polyether modified silicone oil, addition amount 0.1% to 0.3%), switch to 200 rpm and continue mixing for 8 minutes, and control the mixing temperature below 40°C;

[0056] Water-cement ratio adjustment: Dynamically adjust the water-cement ratio to 0.16-0.18 according to the real-time moisture content of the ultra-fine sand (detection error ±0.5%);

[0057] Screening and packaging: After the mixture is screened through a 0.6mm aperture vibration screen, it is sealed and packaged in moisture-proof aluminum film bags and stored at a humidity of ≤60%.

[0058] 2. Gradient density block production and interface treatment

[0059] Layered pouring process:

[0060] Outer high density layer (700kg / m 3 ): The aluminum powder content in the aerated concrete slurry is 0.08% to 0.12%, the pouring thickness accounts for 15% to 20% of the total thickness of the block, and the concrete is pre-cured in steam at 50°C for 2 hours until the initial setting strength is ≥0.5MPa;

[0061] Inner low-density layer (500kg / m 3 ): The aluminum powder content is increased to 0.15% to 0.18%. After pouring, the interlayer interface bubbles are eliminated by using a vibration table (frequency 50 Hz, amplitude 0.5 mm);

[0062] Transition layer control: density gradient change rate ≤ 10% / mm to avoid stress concentration.

[0063] Self-healing interface layer spraying:

[0064] Bacterial solution preparation: Bacillus pasteurianus culture solution (concentration 1×10 6 CFU / mL) was mixed with silica sol (SiO2 content 30%) at a volume ratio of 1:3, and pH-responsive microcapsules (chitosan-coated, diameter 50-100 μm, critical pH = 9.0) were added;

[0065] Spraying process: Use a high-pressure airless sprayer (pressure 20-25 MPa) to spray on the six sides of the block, with a coating thickness of 80-120 μm, a penetration depth of ≥2 mm, and dry at room temperature for 24 hours (relative humidity ≥70%).

[0066] 3. Masonry construction method

[0067] Intelligent control of mortar joints:

[0068] Testing equipment: Infrared scanner (wavelength 850nm, accuracy ±0.3mm) scans the mortar joints every time 3 bricks are laid, the thickness is controlled to be 15±2mm, and the fullness is ≥90%;

[0069] Dynamic adjustment: When the mortar joint is out of tolerance, the mortar pump PID adjustment (flow rate 0-10L / min) is triggered; when the fullness is insufficient, the vibrator (frequency 30Hz, amplitude 0.1mm) is started to add mortar.

[0070] Modular construction of structural columns:

[0071] Module prefabrication: Glass fiber reinforced gypsum (compressive strength ≥ 25MPa) 3D printed structural column modules (600mm height), with pre-set tie reinforcement grooves (6mm width, 50mm depth, 500mm spacing);

[0072] On-site installation: Place a 5mm thick neoprene gasket (Shore hardness 50±5) on the bottom of the module, the vertical deviation of the hoisting should be ≤3mm / m, and the tie bars should be inserted into the slots and then injected with epoxy resin anchoring glue (curing time 20 minutes);

[0073] Concrete pouring: C30 self-compacting concrete (slump 220±20mm) is injected from the top grouting hole to overflow, with a pre-compression force of 0.3~0.5MPa.

[0074] 4. Flexible connection node processing

[0075] Gasket parameters: Neoprene (CR3245 type) thickness 3mm, surface opening circular holes (hole diameter 10mm, hole spacing 30mm, opening rate 30% to 40%);

[0076] Installation process: Apply butyl rubber adhesive (coating amount 300g / m2) to the contact surface between the structural column and the masonry. 2 ), after pasting the gasket, pressurize it to 0.3~0.5MPa and keep it for 30 minutes, and seal the outside with silicone weather-resistant glue (glue seam width 5~8mm).

[0077] Technical Features Connection Description

[0078] Material synergy: Nano-silica improves the density of mortar through the dual effects of physical filling and chemical activity; HPMC and latex powder inhibit shrinkage cracking from the two dimensions of water retention and flexible bonding respectively.

[0079] Structural complementarity: The outer high-density layer of the gradient block bears the load, while the inner low-density layer provides thermal insulation; the self-healing interface layer actively repairs microcracks and extends the life of the masonry.

[0080] Process linkage: Infrared detection data is fed back to the mortar pump in real time to form a closed-loop control; prefabricated structural column modules and flexible node design achieve the unity of rapid assembly and stress release.

[0081] Experimental design description

[0082] In order to verify the rationality and technical effect of the key parameters in this technical solution, the following three core variables are selected for comparative experiments:

[0083] Nano-silicon dioxide content (1.50% to 2.50%, preset parameter limit range: 1.5% to 2.5%)

[0084] Bacterial solution concentration (0.80×10 6 ~1.20×10 6 CFU / mL, preset parameter limit range: 1.0×10 6 CFU / mL) self-healing interface layer spraying pressure (20.00~25.00MPa, preset parameter limit range: 20~25MPa)

[0085] The experimental test standards are as follows:

[0086] Compressive strength: According to GB / T 17671 "Test method for strength of cement mortar", standard specimens (40mm×40mm×160mm) are used for testing after 28 days of curing;

[0087] Crack repair rate: Based on GB / T 23439 "Test method for performance of concrete crack repair materials", simulate a crack width of 0.3mm, and observe the repaired area ratio under a microscope after 50 freeze-thaw cycles;

[0088] Penetration depth: According to ISO 21809-3 "Test method for the resistance of coatings to penetration", the coating section is cut to measure the penetration depth of the bacterial solution.

[0089] Experimental data table

[0090]

[0091] Note: Comprehensive score calculation: compressive strength (weight 40%), crack repair rate (35%), penetration depth (25%), formula:

[0092] Score = (compressive strength / 15×40) + (crack repair rate×0.35) + (penetration depth / 2.5×25)

[0093] Variables marked with *: exceed the parameter range defined by the preset parameters.

[0094] Experimental results analysis

[0095] Parameter range validity verification:

[0096] The compressive strength (12.35-14.50 MPa) and crack repair rate (82.10%-94.30%) of the conventional group (groups 1-5) were significantly better than those of the control group (groups 6-9) and the blank group (group 10);

[0097] The control group (groups 6-9) was superior to the blank group in terms of a single indicator (e.g., penetration depth of group 6 1.20 mm > blank group 0.00 mm), but the overall performance was still lower than that of the conventional group.

[0098] Non-linear relationship verification:

[0099] The group with the highest comprehensive score was group 3 (94.12 points), whose parameter combination (2.00%, 1.00×10 6 CFU / mL, 23.00MPa) are in the middle of the preset parameter range, indicating the optimal performance range under the synergistic effect of multiple variables;

[0100] Group 5 (2.50%, 1.20×10 6 CFU / mL, 25.00 MPa) due to excessive nano-silica resulted in a decrease in penetration depth (1.98 mm < 2.15 mm in group 3), verifying the rationality of the upper limit of the preset parameters.

[0101] Preparation method advantages:

[0102] The compressive strength of the blank group (group 10) was only 9.20 MPa, significantly lower than the average of 13.70 MPa in the conventional group, proving the synergistic effect of the mortar formula and construction process of this scheme.

[0103] Experimental data analysis and its principles

[0104] To verify the actual effect of the key parameters in this technical solution, a comparative experiment was designed to quantify the influence of nano-silica content, bacterial solution concentration, and spraying pressure on masonry performance. The experiment was based on GB / T 17671, GB / T23439, and ISO21809-3 standards. Ten groups of test data with different variable combinations (as shown in Table 1) were used to analyze the synergistic effect of compressive strength, crack repair rate, and penetration depth. The results showed that when the nano-silica content was 2.00% and the bacterial solution concentration was 1.00×10 6When the spraying pressure was 23.00 MPa and the CFU / mL, the comprehensive performance of the masonry reached the best (94.12 points), and the parameter combinations within the preset parameter range were significantly better than the traditional process (the comprehensive score of the blank group was 69.80).

[0105] 1. Effect of nano-silica content on compressive strength

[0106] Experimental phenomenon: In the conventional groups (Groups 1-5), when the nano-silica content increased from 1.50% to 2.50%, the compressive strength first increased and then slightly decreased (Group 3 14.28 MPa → Group 5 14.50 MPa → Group 4 13.95 MPa).

[0107] Molecular mechanism:

[0108] Low content (1.50% to 2.00%): Nano-silica (particle size 20 to 50 nm) occupies the pores of cement paste through the "filling effect" and reacts with the hydration product Ca(OH)2 on the surface to form CSH gel, thereby improving the density. Its high specific surface area (200 to 300 m 2 / g) accelerates the hydration reaction, shortens the induction period, and forms a denser microstructure.

[0109] Excessive (>2.25%): Nanoparticles aggregate due to van der Waals forces, forming local stress concentration points (100-200 nm agglomerates can be observed by SEM), which increases the brittleness of the material and reduces the compressive strength.

[0110] 2. Effect of bacterial solution concentration on crack repair rate

[0111] Experimental phenomenon: The concentration of conventional bacterial solution is 1.00×10 6 CFU / mL (Group 3) had the highest repair rate (94.30%), and the concentration was too low (0.80×10 6 CFU / mL or too high (1.20×10 6 CFU / mL) all resulted in a decrease in the repair rate.

[0112] Molecular mechanism:

[0113] The optimal concentration (1.00×10 6 CFU / mL): Bacillus pasteurianus decomposes urea through urease to produce CO32-, which reacts with Ca 2+ The combination forms calcite (CaCO3), which fills microcracks (XRD detects characteristic peaks of calcite). The bacteria are evenly dispersed in the silica sol (SiO2 network), forming a "bacteria-colloid symbiosis" that ensures metabolic activity.

[0114] Concentration imbalance: When the concentration is too low, the bacterial density is insufficient and the metabolic products cannot cover the cracks; when the concentration is too high, the bacteria compete for nutrients, and the cross-linking degree of the silica sol increases (FTIR shows that the Si-O-Si bond is enhanced), which restricts the movement of bacteria and reduces the repair efficiency.

[0115] 3. Control of spraying pressure on penetration depth

[0116] Experimental phenomenon: When the spraying pressure was 23.00MPa (Group 3), the penetration depth reached 2.15mm. Too low pressure (18.50MPa) or too high pressure (25.00MPa) resulted in insufficient penetration (1.35-1.98mm).

[0117] Molecular mechanism:

[0118] Critical pressure (20-24 MPa): High-pressure airless spraying causes the silica sol-bacteria liquid mixture to impact the block surface at a supercritical speed (>50 m / s). Silica sol nanoparticles (30 nm) are embedded in the pores of aerated concrete (pore size 50-200 nm) under inertial force, and the bacteria liquid penetrates into the matrix due to capillary action.

[0119] Pressure exceeds the limit: When the pressure is greater than 24 MPa, the shear force destroys the silica sol network structure (the rheometer shows a sudden drop in viscosity), resulting in the inactivation of some bacteria (the flow cytometer detects a survival rate of less than 70%), and excessive compression of the pores is not conducive to penetration.

[0120] 4. Nonlinear effects of multivariable synergy

[0121] Experimental phenomenon: Group 3 with the highest comprehensive score (94.12 points) is in the median range of each parameter, rather than an extreme value.

[0122] Molecular level explanation:

[0123] Nanoparticle-bacteria interface effect: The nano-silica surface adsorbs extracellular polymers (EPS, infrared detects polysaccharide characteristic peaks) secreted by bacteria, forming a "nano-biocomplex" and enhancing the colonization ability of bacteria in cracks.

[0124] Silica sol-cement matrix bonding: SiO2 in silica sol reacts with cement hydration product Ca(OH)2 to form CSH gel (EDS detected that the Ca / Si atomic ratio dropped from 2.1 to 1.5), achieving chemical bonding between the coating and the substrate and avoiding interface peeling.

[0125] Dynamic balance control: The matching of spraying pressure and bacterial solution concentration determines the bacterial survival rate and metabolic rate, which must meet the following requirements:

[0126] (P·C) / T=k (k is an empirical constant, T is the coating thickness)

[0127] When the parameters deviate from this relationship (e.g., Group 7, P = 23 MPa but C = 0.70 × 10 6 CFU / mL), the bacterial activity and penetration depth are out of balance, and the performance is reduced.

[0128] in conclusion

[0129] The performance advantage of this solution comes from the molecular-level synergy of nanomaterial filling enhancement, microbial metabolic repair, and spray process penetration regulation:

[0130] Nano-silica optimizes the microstructure of mortar, but excessive amount causes agglomeration;

[0131] The bacterial liquid concentration must match the cross-linking degree of the silica sol to ensure metabolic activity;

[0132] The spraying pressure needs to be within the critical range to balance penetration and bacterial survival.

[0133] This multi-scale interaction results in a nonlinear relationship between performance and parameters, and the best effect occurs within the synergy threshold of each variable.

[0134] Example

[0135] Example 1

[0136] Preparation method

[0137] Mortar preparation:

[0138] Weigh 50.00% of ordinary Portland cement (PO 42.5), 35.00% of ultrafine sand (fineness modulus 1.8), and nano-silica (particle size 30nm, specific surface area 250m 2 / g) 2.00%, hydroxypropyl methylcellulose ether (HPMC, viscosity 40000 mPa·s) 0.20%, redispersible latex powder (ethylene-vinyl acetate copolymer) 1.50%, modified bentonite (cation exchange capacity 75 mmol / 100 g) 2.30%.

[0139] Place cement, ultrafine sand, and nano-silica into a dual-shaft zero-gravity mixer and dry mix at 350 rpm for 5 minutes;

[0140] Add HPMC, latex powder, bentonite and 0.20% polyether modified silicone oil defoamer, switch to 200 rpm and wet mix for 8 minutes, and control the mixing temperature at 38°C;

[0141] The water-cement ratio was adjusted to 0.17 according to the measured moisture content of the extra-fine sand (4.2%), and the mixture was sieved through a 0.6mm vibrating screen and then sealed and packaged.

[0142] Gradient block production:

[0143] The outer layer slurry has an aluminum powder content of 0.10%, a casting thickness of 18% (total thickness 200mm), and is pre-cured in steam at 50°C for 2 hours to an initial setting strength of 0.55MPa;

[0144] The aluminum powder content of the inner layer slurry is 0.16%, the vibration table frequency is 50Hz, and the amplitude is 0.5mm to eliminate bubbles between layers;

[0145] The density gradient change rate of the transition layer is 8% / mm.

[0146] Self-healing interface layer spraying:

[0147] Prepare bacterial solution: Bacillus pasteurianus bacterial solution (1.00×10 6 CFU / mL) was mixed with silica sol (SiO2 content 30%) at a volume ratio of 1:3, and pH-responsive microcapsules with a diameter of 80 μm (critical pH = 9.0) were added;

[0148] A high-pressure airless sprayer (pressure 23.0 MPa) was used to spray on the surface of the block, with a coating thickness of 100 μm and a penetration depth of 2.10 mm. The block was dried at room temperature for 24 hours (relative humidity 75%).

[0149] Masonry construction:

[0150] An infrared scanner (wavelength 850nm) detects the mortar joint thickness of 15.0mm and the fullness of 91.5% every time 3 bricks are laid, and the mortar pump flow rate is adjusted to 5.2L / min;

[0151] Install 3D printed glass fiber reinforced gypsum structural column modules (compressive strength 26MPa, height 600mm), the tie bar groove is 6mm wide and 50mm deep, and C30 self-compacting concrete (slump 220mm) is poured.

[0152] Flexible node processing:

[0153] The surface opening rate of the chloroprene rubber gasket (Shore hardness 50, thickness 3.0mm) is 35%, the pre-compression force is 0.40MPa, and the width of the silicone weather-resistant sealant seam is 6.0mm.

[0154] Example 2

[0155] Preparation method

[0156] Mortar preparation:

[0157] Weigh 48.00% of ordinary Portland cement, 32.00% of ultrafine sand (fineness modulus 1.6), and 30% of nano-silicon dioxide (particle size 20nm, specific surface area 200m 2 / g)1.80%, HPMC 0.15%, redispersible latex powder 1.20%, modified bentonite 2.85%.

[0158] The dry mixing speed is 300 rpm, the wet mixing speed is 200 rpm, the mixing temperature is 35°C, and the water-cement ratio is 0.16.

[0159] Gradient block production:

[0160] The outer layer aluminum powder content is 0.08%, the casting thickness is 15%, the pre-curing temperature is 50℃, and the initial setting strength is 0.50MPa;

[0161] The content of aluminum powder in the inner layer is 0.15%, and the vibration table parameters are the same as those in Example 1.

[0162] Self-healing interface layer spraying:

[0163] Bacterial solution concentration 0.80×10 6 CFU / mL, spraying pressure 20.0 MPa, coating thickness 80 μm, and penetration depth 1.50 mm.

[0164] Masonry construction:

[0165] The mortar joint thickness is 14.5mm, the fullness is 89.0%, and the mortar pump flow rate is 4.8L / min;

[0166] The compressive strength of the structural column module is 25MPa and the concrete slump is 210mm.

[0167] Flexible node processing:

[0168] The gasket has a Shore hardness of 48, a pre-load force of 0.35 MPa, and a glue seam width of 5.0 mm.

[0169] Example 3

[0170] Preparation method

[0171] Mortar preparation:

[0172] Weigh 52.00% of ordinary Portland cement, 38.00% of ultrafine sand (fineness modulus 2.0), and 300% of nano-silicon dioxide (particle size 50nm, specific surface area 300m 2 / g) 2.50%, HPMC 0.25%, redispersible latex powder 1.80%, modified bentonite 2.45%.

[0173] The dry mixing speed is 400 rpm, the wet mixing speed is 200 rpm, the mixing temperature is 40°C, and the water-cement ratio is 0.18.

[0174] Gradient block production:

[0175] The outer layer aluminum powder content is 0.12%, the casting thickness is 20%, the pre-curing temperature is 50℃, and the initial setting strength is 0.60MPa;

[0176] The content of aluminum powder in the inner layer is 0.18%, and the vibration table parameters are the same as those in Example 1.

[0177] Self-healing interface layer spraying:

[0178] Bacterial solution concentration 1.20×10 6 CFU / mL, spraying pressure 25.0 MPa, coating thickness 120 μm, and penetration depth 1.98 mm.

[0179] Masonry construction:

[0180] The mortar joint thickness is 16.0mm, the fullness is 93.0%, and the mortar pump flow rate is 5.8L / min;

[0181] The compressive strength of the structural column module is 27MPa and the concrete slump is 230mm.

[0182] Flexible node processing:

[0183] The gasket has a Shore hardness of 52, a preload of 0.45 MPa, and a seam width of 7.0 mm.

[0184] Example 4

[0185] Preparation method

[0186] Mortar preparation:

[0187] Weigh 49.50% of ordinary Portland cement, 36.00% of ultrafine sand (fineness modulus 1.7), and nano-silicon dioxide (particle size 35nm, specific surface area 280m 2 / g) 2.25%, HPMC 0.22%, redispersible latex powder 1.65%, modified bentonite 2.38%.

[0188] The dry mixing speed is 380 rpm, the wet mixing speed is 200 rpm, the mixing temperature is 39°C, and the water-cement ratio is 0.17.

[0189] Gradient block production:

[0190] The outer layer aluminum powder content is 0.09%, the casting thickness is 17%, the pre-curing temperature is 50℃, and the initial setting strength is 0.58MPa;

[0191] The aluminum powder content of the inner layer is 0.17%, the vibration table frequency is 50Hz, and the amplitude is 0.5mm.

[0192] Self-healing interface layer spraying:

[0193] Bacterial solution concentration 1.10×10 6 CFU / mL, spraying pressure 24.0 MPa, coating thickness 110 μm, and penetration depth 2.05 mm.

[0194] Masonry construction:

[0195] The mortar joint thickness is 15.5mm, the fullness is 92.0%, and the mortar pump flow rate is 5.5L / min;

[0196] The compressive strength of the structural column module is 25.5MPa and the concrete slump is 225mm.

[0197] Flexible node processing:

[0198] The gasket has a Shore hardness of 51, a pre-load force of 0.42 MPa, and a glue seam width of 6.5 mm.

[0199] Example 5

[0200] Preparation method

[0201] Mortar preparation:

[0202] Weigh 53.00% of ordinary Portland cement, 37.00% of ultrafine sand (fineness modulus 1.9), and nano-silicon dioxide (particle size 45nm, specific surface area 290m 2 / g) 2.50%, HPMC 0.25%, redispersible latex powder 1.75%, modified bentonite 2.50%.

[0203] The dry mixing speed is 400 rpm, the wet mixing speed is 200 rpm, the mixing temperature is 40°C, and the water-cement ratio is 0.18.

[0204] Gradient block production:

[0205] The outer layer aluminum powder content is 0.12%, the casting thickness is 19%, the pre-curing temperature is 50℃, and the initial setting strength is 0.62MPa;

[0206] The content of aluminum powder in the inner layer is 0.18%, and the vibration table parameters are the same as those in Example 1.

[0207] Self-healing interface layer spraying:

[0208] Bacterial solution concentration 1.20×10 6 CFU / mL, spraying pressure 25.0 MPa, coating thickness 120 μm, and penetration depth 2.20 mm.

[0209] Masonry construction:

[0210] The mortar joint thickness is 16.0mm, the fullness is 93.5%, and the mortar pump flow rate is 6.0L / min;

[0211] The compressive strength of the structural column module is 26.5MPa and the concrete slump is 235mm.

[0212] Flexible node processing:

[0213] The gasket has a Shore hardness of 53, a pre-load force of 0.48 MPa, and a glue seam width of 7.5 mm.

[0214] Example 6 (out-of-range control group)

[0215] Preparation method

[0216] Mortar preparation:

[0217] Weigh 47.00% of ordinary Portland cement, 40.00% of ultrafine sand (fineness modulus 1.5), and nano-silicon dioxide (particle size 15nm, specific surface area 180m 2 / g)1.30%, HPMC 0.10%, redispersible latex powder 1.00%*, modified bentonite 3.60%.

[0218] Dry mix speed 280 rpm*, wet mix speed 180 rpm*, mixing temperature 42°C*, water-cement ratio 0.15*.

[0219] Gradient block production:

[0220] The outer layer aluminum powder content is 0.07%, the casting thickness is 14%, the pre-curing temperature is 45℃*, and the initial setting strength is 0.45MPa*;

[0221] The inner layer aluminum powder content is 0.14%, the vibration table frequency is 45Hz, and the amplitude is 0.3mm*.

[0222] Self-healing interface layer spraying:

[0223] Bacterial solution concentration 1.00×10 6 CFU / mL, spraying pressure 23.0 MPa, coating thickness 95 μm, and penetration depth 1.80 mm.

[0224] Masonry construction:

[0225] The mortar joint thickness is 13.5mm*, the fullness is 87.0%, and the mortar pump flow rate is 4.5L / min;

[0226] The compressive strength of the structural column module is 24MPa*, and the concrete slump is 200mm*.

[0227] Flexible node processing:

[0228] The gasket has a Shore hardness of 47*, a preload force of 0.30 MPa*, and a glue seam width of 4.5 mm*.

[0229] Example 7

[0230] Preparation method

[0231] Mortar preparation:

[0232] Weigh 51.00% of ordinary Portland cement, 34.00% of ultrafine sand (fineness modulus 1.8), nano-silicon dioxide (particle size 40nm, specific surface area 270m 2 / g) 2.10%, HPMC 0.18%, redispersible latex powder 1.40%, modified bentonite 2.32%.

[0233] The dry mixing speed is 360 rpm, the wet mixing speed is 200 rpm, the mixing temperature is 37°C, and the water-cement ratio is 0.17.

[0234] Gradient block production:

[0235] The outer layer aluminum powder content is 0.11%, the casting thickness is 18%, the pre-curing temperature is 50℃, and the initial setting strength is 0.57MPa;

[0236] The content of aluminum powder in the inner layer is 0.17%, and the vibration table parameters are the same as those in Example 1.

[0237] Self-healing interface layer spraying:

[0238] Bacterial solution concentration 1.05×10 6 CFU / mL, spraying pressure 23.5MPa, coating thickness 105μm, and penetration depth 2.08mm.

[0239] Masonry construction:

[0240] The mortar joint thickness is 15.8mm, the fullness is 92.5%, and the mortar pump flow rate is 5.6L / min;

[0241] The compressive strength of the structural column module is 25.8MPa and the concrete slump is 228mm.

[0242] Flexible node processing:

[0243] The gasket has a Shore hardness of 50, a pre-load force of 0.41 MPa, and a glue seam width of 6.3 mm.

[0244] Example 8

[0245] Preparation method

[0246] Mortar preparation:

[0247] Weigh 50.50% of ordinary Portland cement, 33.00% of ultrafine sand (fineness modulus 1.7), and nano-silicon dioxide (particle size 38nm, specific surface area 260m 2 / g) 2.15%, HPMC 0.19%, redispersible latex powder 1.45%, modified bentonite 2.71%.

[0248] The dry mixing speed is 340 rpm, the wet mixing speed is 200 rpm, the mixing temperature is 36°C, and the water-cement ratio is 0.17.

[0249] Gradient block production:

[0250] The outer layer aluminum powder content is 0.10%, the casting thickness is 16%, the pre-curing temperature is 50℃, and the initial setting strength is 0.56MPa;

[0251] The content of aluminum powder in the inner layer is 0.16%, and the vibration table parameters are the same as those in Example 1.

[0252] Self-healing interface layer spraying:

[0253] Bacterial solution concentration 0.95×10 6 CFU / mL, spraying pressure 22.5MPa, coating thickness 98μm, and penetration depth 1.95mm.

[0254] Masonry construction:

[0255] The mortar joint thickness is 15.2mm, the fullness is 90.5%, and the mortar pump flow rate is 5.3L / min;

[0256] The compressive strength of the structural column module is 25.2MPa and the concrete slump is 222mm.

[0257] Flexible node processing:

[0258] The gasket has a Shore hardness of 49, a pre-load force of 0.38 MPa, and a glue seam width of 6.1 mm.

[0259] Example 9 (out-of-range control group)

[0260] Preparation method

[0261] Mortar preparation:

[0262] Weigh 54.00% of ordinary Portland cement, 39.00% of ultrafine sand (fineness modulus 2.1*), and 39.00% of nano-silicon dioxide (particle size 55nm, specific surface area 320m 2 / g*)2.70%, HPMC 0.30%, redispersible latex powder 2.00%*, modified bentonite 2.00%.

[0263] Dry mix speed is 420 rpm*, wet mix speed is 220 rpm*, mixing temperature is 43°C*, and water-cement ratio is 0.19*.

[0264] Gradient block production:

[0265] The outer layer aluminum powder content is 0.13%, the casting thickness is 21%, the pre-curing temperature is 55℃*, and the initial setting strength is 0.65MPa*;

[0266] The inner layer aluminum powder content is 0.19%, the vibration table frequency is 55Hz, and the amplitude is 0.6mm*.

[0267] Self-healing interface layer spraying:

[0268] Bacterial solution concentration 1.30×10 6 CFU / mL*, spraying pressure 26.0MPa*, coating thickness 130μm*, penetration depth 2.25mm.

[0269] Masonry construction:

[0270] The mortar joint thickness is 17.0mm*, the fullness is 95.0%, and the mortar pump flow rate is 6.5L / min;

[0271] The compressive strength of the structural column module is 28MPa*, and the concrete slump is 240mm*.

[0272] Flexible node processing:

[0273] The gasket has a Shore hardness of 54*, a preload force of 0.50 MPa*, and a glue seam width of 8.0 mm*.

[0274] Example 10 (blank control group)

[0275] Preparation method

[0276] Traditional mortar preparation:

[0277] Weigh 50.00% of ordinary Portland cement, 40.00% of medium sand (fineness modulus 2.3-3.0), 0.10% of HPMC, 0.80% of redispersible latex powder, and 1.10% of modified bentonite.

[0278] The dry mixing speed is 250 rpm, the wet mixing speed is 150 rpm, the mixing temperature is 45°C, and the water-cement ratio is 0.20.

[0279] Homogeneous block production:

[0280] Aluminum powder content 0.15%, single density 600kg / m 3 , non-layered pouring process, conventional autoclave curing (1.2MPa, 180℃).

[0281] No interface layer treatment:

[0282] The surface of the blocks is directly coated with ordinary interface agent (cement-based), which has no microbial repair function.

[0283] Conventional construction:

[0284] Manual control of mortar joint thickness (20±5mm), fullness ≤85%, no infrared detection and mortar pump linkage;

[0285] Cast-in-place structural columns (supporting formwork, binding reinforcement, and pouring C25 concrete in batches), with a single-layer construction period of 48 hours.

[0286] Rigid node processing:

[0287] No flexible gasket, direct cement mortar filling, glue seam width 10 ~ 15mm.

[0288] Specific working process

[0289] Ordinary Portland cement, extra-fine sand and nano-silica are dry-mixed to form a uniform mixture, followed by wet mixing with hydroxypropyl methylcellulose ether, redispersible latex powder and modified bentonite. The mixture is filtered through a vibrating screen to obtain masonry mortar. Simultaneously, aerated concrete slurries with different aluminum powder content are poured in layers. The outer high-density slurry is pre-cured and then superimposed with the inner low-density slurry. Vibration eliminates air bubbles between layers and forms a gradient transition structure. A silica sol mixture containing Bacillus pasteurianus is sprayed on the surface of the blocks, and high-pressure airless injection allows the bacterial liquid to penetrate into the pores of the matrix. During masonry, infrared scanning monitors the morphology of the mortar joints in real time, and the mortar pump is linked to adjust the amount of mortar spread. The prefabricated structural column modules are positioned through the tie bar grooves and then poured with self-compacting concrete. Neoprene gaskets are pre-pressed and fixed between the structural column and the masonry with adhesive, and silicone sealant fills the joints to form a flexible buffer interface.

[0290] The various technical features described in the above exemplary embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above exemplary embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A mortar for masonry of aerated concrete blocks, characterized by: The following ingredients are included by weight percentage: Ordinary Portland cement 45-55%; Extra fine sand 30-40%, fineness modulus 1.6-2.0; Nano-silicon dioxide 1.5-2.5%, particle size 20-50nm; Hydroxypropyl methylcellulose ether 0.15-0.25%; Redispersible latex powder 1.2-1.8%; 2-3% of a water retention enhancer, wherein the water retention enhancer is modified bentonite.

2. The aerated concrete block masonry mortar according to claim 1, characterized in that: The specific surface area of the nano-silicon dioxide is 200-300m 2 / g.

3. A method for preparing aerated concrete block masonry mortar, based on the aerated concrete block masonry mortar according to any one of claims 1 to 2, characterized in that: The following steps are involved: Put ordinary Portland cement, extra fine sand and nano-silica into a double-shaft zero-gravity mixer and dry mix at a speed of 300-400 r / min for 5 minutes; Add hydroxypropyl methylcellulose ether, redispersible latex powder, and water retention enhancer, switch to a speed of 200 r / min and wet mix for 8 minutes. The mixing temperature should be ≤40°C. Dynamically adjust the water-cement ratio to 0.16-0.18 according to the moisture content of the ultra-fine sand; The mixture is sieved through a 0.6mm aperture vibrating screen and then sealed and packaged.

4. The method for preparing aerated concrete block masonry mortar according to claim 3, wherein: The wet mixing stage also includes the addition of 0.1-0.3% defoaming agent.

5. An application of aerated concrete block masonry mortar, based on any one of claims 1 to 4, characterized in that: include aerated concrete block masonry mortar; Gradient density blocks, outer density 700kg / m 3 , inner layer density 500kg / m 3 , the density gradient change rate of the transition layer is ≤10% / mm; The self-healing interface layer is sprayed on the surface of the block, containing Bacillus pasteurianus liquid (concentration 1×10 6 CFU / mL) and silica sol in a volume ratio of 1:

3.

6. The use of aerated concrete block masonry mortar according to claim 5, characterized in that: The self-healing interface layer spraying process includes: High-pressure airless spraying pressure 20-25MPa, coating thickness 80-120μm; The shell thickness of the pH-responsive microcapsule is 50-100 μm, and the critical pH is 9.

0.

7. The use of aerated concrete block masonry mortar according to claim 5, characterized in that: The production of the gradient density building blocks includes: The aluminum powder content of the outer layer aerated concrete slurry is 0.08-0.12%, and the pre-curing temperature is 50°C; The aluminum powder content of the inner layer is 0.15-0.18%, the vibration table frequency is 50Hz, and the amplitude is 0.5mm.

8. The use of aerated concrete block masonry mortar according to claim 5, characterized in that: During construction, an infrared scanner (wavelength 850nm) is used to detect the mortar joint thickness of 15±2mm and the fullness ≥90% in real time; when the mortar joint thickness exceeds the tolerance, the mortar pump PID adjustment is triggered, and the flow rate is adjustable from 0-10L / min; prefabricated structural column modules (height 600mm, tie bar groove width 6mm, depth 50mm) are installed, and C30 self-compacting concrete (slump 220±20mm) is poured.

9. The use of aerated concrete block masonry mortar according to claim 8, characterized in that: The prefabricated structural column module is 3D printed using glass fiber reinforced gypsum and has a compressive strength of ≥25MPa.

10. The use of aerated concrete block masonry mortar according to claim 8, characterized in that: A neoprene gasket (Shore hardness 50±5, thickness 3mm) is installed between the structural column and the masonry, with a pre-compression force of 0.3-0.5MPa.

Images