A lime-based cementitious composition and a grouting cementitious material

Abstract

The present application provides a lime-based cementitious composition, comprising natural hydraulic lime, limestone, glutinous rice slurry, water reducing agent, expansive agent and water repellent agent. The present application also provides a grouting cementitious material prepared by using the composition, which has good mechanical properties, durability and compatibility, and is suitable for ancient building repair work.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a lime-based cementitious material composition and a grouting adhesive containing the composition, as well as the application of the composition and the grouting adhesive in the restoration of ancient buildings. Background Technology

[0002] Ancient brick / stone / rock and earth buildings are an important part of China's cultural heritage, possessing a rich historical and cultural background. However, under the influence of various natural factors and human activities, they have suffered various forms of damage such as weathering, hollowing, and cracking. Among these, the repair of cracks is of utmost urgency to prevent the collapse of ancient buildings.

[0003] Currently, most of the materials used for repairing cracks in ancient brick / stone / rock and soil buildings are still silicate cement mortar. However, this type of repair material has the following problems: (1) Using cement mortar to repair ancient buildings does not conform to the principle of "restoring the old as before" in the preservation of cultural relics. Most of the cementing materials used in ancient buildings are lime-based cementing materials. If cement is used as the cementing material for repair, its appearance after hardening is mostly cold gray, which will obviously cause a lack of coordination between the repaired and unrepaired parts in terms of appearance; (2) Due to the inconsistency between the compatibility and shrinkage and expansion coefficients of cement mortar and other repair materials with ancient brick / stone / rock and soil buildings, the use of cement-based mortar as a repair material will result in "secondary damage" in a short period of time; (3) Existing repair materials for cracks in ancient brick / stone / rock and soil buildings have low bonding strength at the interface between new and old materials, low overall strength, and are prone to cracking.

[0004] Therefore, there is a need to develop more materials for repairing cracks in ancient brick / stone / rock and soil buildings that can meet the principles of cultural relic restoration and have good mechanical properties, durability and compatibility. Summary of the Invention

[0005] To address one of the aforementioned problems in existing technologies, this invention provides a novel grouting and bonding material for the repair of cracks in ancient brick / stone / soil-based buildings. This material overcomes the shortcomings of previous repair materials, such as poor compatibility, poor mechanical properties, and inconsistent appearance, and can be applied to ancient building restoration projects.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a lime-based cementitious material composition comprising natural hydraulic lime, limestone, glutinous rice paste, water-reducing agent, expanding agent, and water-repellent agent.

[0008] This invention uses natural hydraulic lime as the main cementing material, and adds limestone and glutinous rice paste, and uses additives such as water-reducing agents, expansion agents and water-repellent agents to further improve the fluidity, compressive strength, tensile bond strength and other mechanical properties of natural hydraulic lime-based slurry, and enhance its compatibility with the cracked matrix of ancient buildings.

[0009] In this invention, no special limitations are placed on the natural hydraulic lime. According to some embodiments of the present invention, the natural hydraulic lime includes NHL5. In this invention, no special limitations are placed on the performance of the NHL5, as long as it meets the performance requirements for NHL5 in BSEN459-1—2015.

[0010] According to some embodiments of the present invention, the mass ratio of the natural hydraulic lime to the sum of the masses of the limestone and glutinous rice paste is (0.6-15):1, for example 0.7:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.2:1, 8.5:1, 9:1, 9.5:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15:1; preferably (2.5-10):1, more preferably (5-10):1.

[0011] According to some embodiments of the present invention, the mass ratio of limestone to glutinous rice paste is (0.15-5):1, for example 0.17:1, 0.25:1, 0.3:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1.

[0012] According to some embodiments of the present invention, the composition contains 35% to 90% natural hydraulic lime by weight, for example 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 88%, or 90%, preferably 65% ​​to 88%.

[0013] According to some embodiments of the present invention, the limestone content in the composition is 1% to 25% by weight, for example 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22% or 25%, preferably 3% to 20%.

[0014] According to some embodiments of the present invention, the content of glutinous rice paste in the composition is 1% to 30% by weight, for example 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28% or 30%, preferably 3% to 20%.

[0015] According to some embodiments of the present invention, the water-reducing agent content in the composition is 0.01% to 0.5% by weight, for example 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%, preferably 0.1% to 0.3%.

[0016] According to some embodiments of the present invention, the content of the expanding agent in the composition is 0.1% to 15% by weight, for example 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, preferably 3% to 12%.

[0017] According to some embodiments of the present invention, the water-repellent agent in the composition is 0.01% to 1% by weight, for example 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, preferably 0.1% to 0.7%.

[0018] According to some embodiments of the present invention, the composition comprises, by weight percentage, 35% to 90% natural hydraulic lime, 1% to 25% limestone, 1% to 30% glutinous rice paste, 0.01% to 0.5% water-reducing agent, 0.1% to 15% expanding agent, and 0.01% to 1% water-repellent agent.

[0019] According to a preferred embodiment of the present invention, the composition comprises, by weight percentage, 65%–88% natural hydraulic lime, 3%–20% limestone, 3%–20% glutinous rice paste, 0.1%–0.3% water-reducing agent, 3%–12% expanding agent, and 0.1%–0.7% water-repellent agent.

[0020] In this invention, limestone powder is preferably used. The present invention does not impose any particular limitation on the limestone powder; commercially available limestone powder may be used. According to some embodiments of the present invention, the fineness of the limestone powder is 200-400 mesh. In some preferred embodiments, the fineness of the limestone powder is 300-350 mesh, for example, 325 mesh.

[0021] In this invention, the glutinous rice paste is prepared by mixing glutinous rice flour and water. This invention does not impose any special limitations on the glutinous rice flour; commercially available glutinous rice flour can be used. According to some embodiments of this invention, the mass ratio of glutinous rice flour to water in the glutinous rice paste is 1:(8-10), for example, 1:8, 1:8.5, 1:9, or 1:9.5. This invention also does not impose any special limitations on the preparation method of the glutinous rice paste; existing known methods can be used.

[0022] According to some embodiments of the present invention, the water-reducing agent is a polycarboxylate water-reducing agent, such as polyester-based high-performance polycarboxylate water-reducing agents, polyether-based high-performance polycarboxylate water-reducing agents, amide / imide-type polycarboxylate water-reducing agents, and amphoteric polycarboxylate water-reducing agents (polyamide-polyethylene glycol branched water-reducing agents). Polyether-based high-performance polycarboxylate water-reducing agents are preferred.

[0023] In this invention, the expansive agent enables natural hydraulic lime-based cementitious materials to exhibit a slight expansion rate, thereby better fulfilling their repair and bonding functions. According to some embodiments of the invention, the expansive agent is a calcium oxide-based expansive agent, preferably a PMC high-performance concrete expansive agent. This invention does not impose any special limitations on the PMC high-performance concrete expansive agent, as long as it conforms to the GB23445 standard.

[0024] The water-repellent agent in this invention can improve the waterproof performance of natural hydraulic lime-based cementitious materials. According to some embodiments of the invention, the water-repellent agent is an organosilicon water-repellent agent, preferably a silane powder water-repellent agent.

[0025] In a second aspect, the present invention provides an injection bonding material comprising the composition described in the first aspect of the present invention, or prepared from raw materials comprising the composition described in the first aspect of the present invention.

[0026] According to some embodiments of the present invention, the water-cement ratio of the injection bonding material is 0.6 to 0.65. The water in the water-cement ratio of the present invention includes the water in the glutinous rice paste of the composition.

[0027] Thirdly, the present invention provides a method for preparing the adhesive material described in the second aspect, comprising:

[0028] The raw materials comprising the natural hydraulic lime, limestone, glutinous rice paste, water-reducing agent, expanding agent and water-repellent agent described in the first aspect of the present invention are mixed with water to obtain the grouting adhesive material.

[0029] Preferably, the water-cement ratio of the injection bonding material is 0.6 to 0.65, wherein the water in the water-cement ratio includes the water in the glutinous rice paste.

[0030] Preferably, the limestone is limestone powder.

[0031] Preferably, the preparation method includes the following steps:

[0032] (1) Mix glutinous rice paste with water to obtain glutinous rice paste liquid;

[0033] (2) Mix the raw materials including natural hydraulic lime, limestone powder, water-reducing agent, expansion agent and water-repellent agent and pour them into a cement mortar mixer. Stir for 230 to 250 seconds, add the glutinous rice slurry obtained in step (1), and continue stirring for 110 to 130 seconds to obtain the grouting bonding material; wherein the total water-cement ratio is 0.6 to 0.65.

[0034] Fourthly, the present invention provides the application of the composition described in the first aspect or the injection bonding material described in the second aspect in the restoration of ancient buildings.

[0035] The beneficial effects of this invention are:

[0036] This invention uses natural hydraulic lime as the main cementing material, combined with appropriate amounts of limestone powder and glutinous rice paste. Limestone powder, as an inert filler with a "ball-like" effect, not only ensures the volume stability of the grout but also improves its fluidity. The amylopectin in the glutinous rice paste undergoes "biomineralization" with the calcium carbonate in the grout. The organic starch and inorganic lime mutually encapsulate and fill each other, forming a dense microstructure that combines strength and toughness. Simultaneously, the anti-corrosion effect of lime inhibits starch decay, ensuring the durability of the grout. The incorporation of limestone powder and glutinous rice paste improves the compressive strength and tensile bond strength of the cementing material, resulting in high durability. The addition of water-reducing agents, expanding agents, and water-repellent agents further enhances the material's fluidity, expansion rate, and waterproofing, improving its compatibility with the cracked substrate of ancient buildings. Furthermore, the application of natural hydraulic lime to ancient buildings can absorb carbon dioxide, making it environmentally friendly. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be described in detail below with reference to specific embodiments and comparative examples. The embodiments described are only some embodiments of the present invention, and not all of them.

[0038] Reagent composition or brand:

[0039] The natural hydraulic lime used in the following embodiments and comparative examples of the present invention is NHL5, and its performance test meets the requirements for NHL5 performance in BSEN459-1—2015.

[0040] The limestone powder used was commercially available 325 mesh limestone powder;

[0041] The glutinous rice paste used is made by boiling commercially available glutinous rice flour and water. The mass ratio of glutinous rice flour to water in the glutinous rice paste is 1:8.

[0042] The water-reducing agent used is BASF 2651 high-performance polycarboxylate powder water-reducing agent;

[0043] The expansive agent used is PMC concrete expansive agent from the brand Panier;

[0044] The hydrophobic agent used was silane powder hydrophobic agent T-618 produced by Nanchang Tianrun New Materials Co., Ltd.

[0045] Example 1

[0046] This embodiment provides a lime-based cementitious material composition, comprising the following components by weight percentage:

[0047]

[0048]

[0049] Example 2-15

[0050] Examples 2-15 each provide a lime-based cementitious material composition, the specific composition (mass percentage) of which is shown in Table 1.

[0051] Comparative Examples 1-6

[0052] Comparative Examples 1-6 each provide a lime-based cementitious material composition, the specific composition (mass percentage) of which is shown in Table 1.

[0053] Table 1

[0054]

[0055]

[0056] Grouting materials were prepared by mixing the lime-based cementitious material compositions from Examples 1-15 and Comparative Examples 1-6 with water, with a total water-cement ratio of 0.65 (the ratio of total water volume to the sum of the mass of natural hydraulic lime and glutinous rice flour).

[0057] The preparation method is as follows:

[0058] (1) First, weigh the required amounts of natural hydraulic lime, limestone powder, glutinous rice paste, PMC concrete expansion agent, polycarboxylate powder water-reducing agent, silane powder water-repellent agent, and tap water required to achieve a total water-cement ratio of 0.65 according to the mass percentage of each component in Table 1.

[0059] (2) Pour the weighed tap water into the glutinous rice paste and mix well to obtain the glutinous rice paste.

[0060] (3) Pour the weighed components other than glutinous rice paste and water into a JJ-5 cement mortar mixer. Stir slowly for 120 seconds, then stir quickly for 120 seconds to make them evenly mixed. Add the glutinous rice paste from step (2), and then immediately start the mixer. Stir slowly for 30 seconds, then stir quickly for 90 seconds.

[0061] The preparation methods of glutinous rice paste in each embodiment and comparative example are as follows:

[0062] Taking the preparation of 900g of glutinous rice paste as an example:

[0063] (1) Weigh 100g of glutinous rice flour and 850g of tap water, pour them all into a pot and mix well.

[0064] (2) Heat it at 200°C with an induction cooker while stirring. When the glutinous rice paste becomes viscous, adjust the temperature to 100°C and continue heating and stirring until the glutinous rice paste is 900g.

[0065] Because glutinous rice paste is not easy to preserve, it is generally cooked and used immediately during the experiment.

[0066] Effect test:

[0067] The grouting material prepared above was tested for properties such as fluidity, setting time, compressive strength, tensile bond strength, and expansion rate. The test results are shown in Table 2.

[0068] Test methods: The fluidity was tested according to GB / T8077-2012 "Test Method for Homogeneity of Concrete Admixtures", the setting time and compressive strength were tested according to EN459-2:2010 "Test Method for Building Lime", and the tensile bond strength, expansion rate and water absorption rate were tested according to JGJ / T70-2009 "Standard for Test Methods of Basic Properties of Building Mortar".

[0069] Table 2

[0070]

[0071]

[0072] Conclusion: The performance test results of Example 1 and Comparative Examples 1-6 show that incorporating limestone powder, glutinous rice paste, polycarboxylate superplasticizer, expanding agent, and water-repellent agent into natural hydraulic lime to prepare grout can significantly enhance the fluidity, volume stability, compressive strength, and tensile bond strength of the grout. The addition of the expanding agent can give the grout a slight expansion rate, thereby better exerting its repair and bonding function. The water-repellent agent further improves the waterproof performance of the grout.

[0073] Within the formulation range of this invention, the NHL grout has a flowability of over 180 mm, an initial setting time of over 4 hours, a final setting time of less than 12 hours, a 28-day compressive strength of over 5 MPa, a 28-day tensile bond strength of over 0.7 MPa, a 28-day expansion rate between 0 and 0.45%, and a water absorption rate of less than 20%, making it more suitable for the repair of ancient brick / stone / rock and soil buildings.

[0074] The embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the terms used herein are descriptive and explanatory, not limiting. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from its scope and spirit. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications having the same function.

Claims

1. A grouting bonding material comprising a lime-based cementitious material composition or prepared from raw materials comprising said composition, said lime-based cementitious material composition comprising natural hydraulic lime, limestone, glutinous rice paste, water-reducing agent, expanding agent and water-repellent agent; The composition comprises, by weight percentage, 65%–88% natural hydraulic lime, 5%–20% limestone, 5%–15% glutinous rice paste, 0.1%–0.3% water-reducing agent, 3%–12% expanding agent, and 0.1%–0.7% water-repellent agent; The ratio of the mass of the natural hydraulic lime to the sum of the masses of the limestone and glutinous rice paste is (2.5–10):1; The mass ratio of limestone to glutinous rice paste is (0.25-5):1; In the glutinous rice paste, the mass ratio of glutinous rice flour to water is 1:(8-10); The water-cement ratio of the injection bonding material is 0.6 to 0.65, and the water in the water-cement ratio includes the water in the glutinous rice paste in the composition.

2. The injection bonding material according to claim 1, characterized in that, The limestone has a fineness of 200-400 mesh.

3. The injection bonding material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent; and / or the expanding agent is a calcium oxide expanding agent; and / or the water-repellent agent is an organosilicon water-repellent agent.

4. The injection bonding material according to claim 1, characterized in that, The water-reducing agent is a polyether-based polycarboxylic acid high-performance water-reducing agent.

5. The injection bonding material according to claim 1, characterized in that, The expansive agent is PMC high-performance concrete expansive agent.

6. The injection bonding material according to claim 1, characterized in that, The hydrophobic agent is a silane powder hydrophobic agent.

7. A method for preparing the injection bonding material according to any one of claims 1-6, comprising: The raw materials, including the natural hydraulic lime, limestone, glutinous rice paste, water-reducing agent, expanding agent and water-repellent agent, are mixed with water to obtain the grouting bonding material.

8. The application of the grouting bonding material according to any one of claims 1 to 6 in the restoration of ancient buildings.

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