Gunning material and method for its preparation

Abstract

The application discloses a grouting material and a preparation method thereof, and belongs to the technical field of road building materials. The problems of low early strength, insufficient frost resistance and easy flow of the grouting material under the conditions of low temperature and large longitudinal slope in high-altitude mountainous areas are solved. The grouting material is composed of dry-mixed components and mixed liquid components. The dry-mixed components comprise 40-55 parts by weight of sulphoaluminate cement, 5-10 parts by weight of silica ash, 10-18 parts by weight of fly ash, 3-6 parts by weight of expanding agent and 0.02-0.15 parts by weight of air entraining component. The air entraining component is rosin thermopolymer and / or triterpene saponin air entraining agent. The mixed liquid components comprise 0.3-0.8 parts by weight of polycarboxylic acid water reducing agent, 0.5-1.5 parts by weight of ethylene glycol antifreeze component, 25-35 parts by weight of water and 8-15 parts by weight of butyl benzene emulsion. The material is mainly used for grouting of asphalt pavement with super large longitudinal slope in high-altitude mountainous areas, and has the properties of early strength, frost resistance and anti-flow at low temperature.

Description

Technical Field

[0001] This invention belongs to the field of road construction materials technology, specifically relating to grouting materials and their preparation methods. Background Technology

[0002] In high-altitude mountainous areas, asphalt pavements are subjected to the combined effects of heavy traffic and extreme weather, often resulting in rutting, cracks, and other defects. Structural repair using grouting materials or semi-flexible pavement injection are common techniques for improving pavement load-bearing capacity and durability. However, these areas are generally characterized by low temperatures, large diurnal temperature variations, long frost periods, and steep longitudinal slopes, revealing several significant problems with conventional grouting materials under these conditions.

[0003] Low-temperature environments significantly impact the hydration reaction of cement-based grouting materials. When the temperature drops to around 0℃, the migration rate of ions in the liquid water decreases dramatically, severely hindering the dissolution and precipitation process of cement particles. The amount of hydration products generated is far lower than under normal temperature conditions, resulting in a significantly prolonged grout setting and hardening time, and extremely slow development of early compressive and flexural strength. Grouted pavements often require long-term closed maintenance, which directly affects road traffic efficiency, especially on high-altitude routes with high traffic dependence. If the grouting layer is subjected to traffic loads prematurely before sufficient strength is achieved, it is highly susceptible to cracking and peeling from the original pavement, leading to secondary damage. While increasing the curing temperature or incorporating antifreeze components can alleviate this problem to some extent, most active heating measures are difficult to implement due to limitations in field construction conditions. The freezing point lowering effect of antifreeze components also has its limits, and the negative impact on other properties must be considered.

[0004] Freeze-thaw cycles are another core factor contributing to the deterioration of grouting materials at high altitudes. Moisture trapped in the capillaries and microcracks within the material freezes and expands at sub-zero temperatures, generating enormous hydrostatic and osmotic pressures. When this stress exceeds the tensile strength of the matrix, it induces the initiation, propagation, and penetration of microcracks, ultimately leading to surface spalling, overall loosening, and strength reduction. Traditional grouting materials are mostly based on ordinary silicate cement, whose pore structures formed by hydration products are often open, large, and highly interconnected, resulting in very limited freeze-thaw resistance after saturation. Introducing microbubbles into the material to provide pressure relief space is a recognized effective method to improve freeze-thaw resistance. However, the stable existence of these bubbles depends on a precise match between grout viscosity, mixing process, and chemical admixtures. Too few bubbles result in insufficient freeze-thaw protection, while too many bubbles or excessively large pore sizes significantly weaken mechanical properties, creating an inherent contradiction. The generation and stabilization of bubbles are particularly challenging during low-temperature mixing and setting processes.

[0005] Grouting construction on steep longitudinal slopes also requires resistance to flow. Under its own weight, the grout undergoes creep or overall slippage along the slope, easily leading to insufficient grout in the upper area and incomplete filling, while the lower area may accumulate too thickly, resulting in insufficient effective grout volume. This uneven filling not only reduces the interlocking effect between the asphalt mixture and the grout layer but also creates stress concentration at the interface, significantly weakening the overall mechanical properties of the composite structure. To suppress flow, the grout needs to possess a certain yield stress or thixotropic recovery capability, but these rheological characteristics often contradict the groutability required for construction. While higher yield stress is beneficial for retention, it increases grouting resistance, making it difficult to fill tiny voids and affecting compaction and bonding.

[0006] Furthermore, the aforementioned three properties—early strength at low temperatures, freeze-thaw resistance, and anti-flow—are often mutually restrictive at the material design level. Pursuing early strength at low temperatures typically requires increasing the activity of cementitious materials or incorporating early strength components, which accelerates slurry thickening, hinders uniform bubble formation and stability, and compresses the grouting operation window. The bubble system introduced to enhance freeze resistance may weaken matrix density, reduce strength contribution, and further amplify the risk of insufficient early load-bearing capacity. Thickening or thickening measures required to improve anti-flow properties are difficult to disperse at low temperatures, easily leading to agglomeration or uneven mixing, resulting in poor slurry homogeneity and consequently weakening the uniformity and reliability of freeze resistance and mechanical properties. Due to the interplay of these issues, existing grouting material preparation technologies struggle to simultaneously meet the comprehensive requirements of early strength at high altitudes, resistance to frequent freeze-thaw cycles, and anti-flow on steep longitudinal slopes, resulting in long-term difficulties in ensuring the quality of pavement grouting under these special service environments. Summary of the Invention

[0007] One object of the embodiments of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0008] The problem lies in addressing the challenges posed by low temperatures and steep longitudinal slopes in high-altitude mountainous areas. Low ambient temperatures slow cement hydration, resulting in insufficient early compressive and flexural strength of grouting materials, making them unable to withstand vehicle loads. Furthermore, insufficient grout viscosity and yield stress make it difficult to resist the gravitational component along the longitudinal slope, leading to grout loss and incomplete filling, ultimately causing secondary road damage. Additionally, conventional grouting materials are prone to internal structural damage under frequent freeze-thaw cycles. Existing preparation technologies struggle to comprehensively address the issues of low-temperature early strength, freeze-thaw resistance, and anti-flow properties.

[0009] This addresses the problem in grouting construction of asphalt pavements on ultra-slender longitudinal slopes where ordinary grouting materials lack thixotropy, causing creeping and flowing along the slope after injection, resulting in voids at the top and accumulation at the bottom, insufficient effective grouting volume, difficulty in forming a continuous and uniform filling body, leading to early defects such as reduced load-bearing capacity and reflective cracking, seriously affecting road safety and service life.

[0010] To achieve the above-mentioned objectives, the present invention employs the following technical solution: A method for preparing a grouting material includes the following steps: 1) Add 40-55 parts by weight of sulfoaluminate cement, 5-10 parts by weight of silica fume, 10-18 parts by weight of fly ash, 3-6 parts by weight of expansive agent, and 0.02-0.15 parts by weight of air-entraining component into a mixer and dry mix at a speed of 60-100 r / min for 2-4 minutes to obtain a dry mix; the air-entraining component is rosin thermal polymer and / or triterpenoid saponin air-entraining agent; 2) Based on the total weight of sulfoaluminate cement, silica fume, fly ash and expansive agent described in step 1) as 100 parts by weight, dissolve 0.3 to 0.8 parts by weight of polycarboxylate superplasticizer and 0.5 to 1.5 parts by weight of ethylene glycol antifreeze component in 25 to 35 parts by weight of water, then add 8 to 15 parts by weight of styrene-butadiene emulsion, and stir evenly to obtain a mixture. 3) Under continuous stirring, add the mixture obtained in step 2) to the dry mixture obtained in step 1) in 2 to 3 portions, with an interval of 30 to 60 seconds between each addition. After all the mixture is added, continue stirring for 3 to 5 minutes to obtain the grouting material.

[0011] Preferably, in the preparation method of the grouting material, in step 1), based on 100 parts by weight of the total weight of sulfoaluminate cement, silica fume, fly ash and expansion agent, 0.05 to 0.5 parts by weight of thixotropic anti-flowing agent is added, wherein the thixotropic anti-flowing agent is magnesium aluminum silicate and / or attapulgite, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0012] Preferably, in the preparation method of the grouting material, the amount of the air-entraining component added is 0.05 to 0.15 parts by weight; based on the total weight of 100 parts by weight of the sulfoaluminate cement, silica fume, fly ash and expanding agent in step 1), the grouting material also contains 0.1 to 0.3 parts by weight of defoamer, the defoamer being a mineral oil-based defoamer and / or a polyether-modified organosilicon defoamer, and the amount of defoamer added is not greater than twice the amount of the air-entraining component added; wherein, in step 3), the mixture obtained in step 2) is added to the dry mixture obtained in step 1) in 2 to 3 portions and stirred for 2 to 3 minutes, then the defoamer is added, and stirring is continued for another 1 to 2 minutes.

[0013] Preferably, in the preparation method of the grouting material, in step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent, 1.5 to 4 parts by weight of a UV-resistant aging component is added. The UV-resistant aging component is rutile nano-titanium dioxide and / or ultrafine calcium carbonate, which are dry-mixed together with the remaining dry mix to obtain the dry mix.

[0014] Preferably, in the preparation method of the grouting material, in step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expanding agent, 0.3 to 1.0 parts by weight of a silane coupling agent is added, wherein the silane coupling agent is γ-aminopropyltriethoxysilane and / or γ-glycidoxypropyltrimethoxysilane, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0015] Preferably, in the preparation method of the grouting material, in step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent, 0.01 to 0.05 parts by weight of a foam stabilizing component is added, wherein the foam stabilizing component is hydroxypropyl methylcellulose ether and / or styrene ether, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0016] Preferably, in the method for preparing the grouting material, in step 1), the thixotropic anti-flowing agent is premixed evenly with an equal mass of fly ash to obtain a thixotropic agent premix, and then the thixotropic agent premix and the remaining dry mix are put into a mixer for dry mixing.

[0017] Preferably, in the preparation method of the grouting material, based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent mentioned in step 1), the grouting material further contains 1.5 to 4 parts by weight of a UV-resistant aging component, wherein the UV-resistant aging component is rutile nano-titanium dioxide and / or ultrafine calcium carbonate; wherein, in step 2), the UV-resistant aging component is first added to the styrene-butadiene emulsion and stirred and dispersed at a speed of 300 to 500 r / min for 5 to 10 minutes to obtain a aging-resistant component-polymer premix, and then the aging-resistant component-polymer premix is ​​added to the mixture mentioned in step 2) and stirred evenly.

[0018] Preferably, in the preparation method of the grouting material, the original particle size of the rutile nano-titanium dioxide is 15-80 nm, and the median particle size D50 of the ultrafine calcium carbonate is 0.5-3 μm.

[0019] A grouting material prepared by any of the methods described above.

[0020] Compared with the prior art, the advantages and beneficial technical effects of the present invention are: This invention utilizes sulfoaluminate cement as the cementitious matrix, leveraging its rapid hardening properties at low temperatures. It is supplemented with silica fume and fly ash to optimize gradation and activity, and incorporates rosin thermal polymers or triterpenoid saponins as air-entraining components to construct a microporous system. Ethylene glycol antifreeze is used to ensure continuous hydration at sub-zero temperatures, and styrene-butadiene emulsion is employed to form an organic-inorganic interpenetrating network. A process of adding the mixture in stages ensures uniform coating of each component. The resulting grouting material hardens rapidly at low temperatures, providing load-bearing strength. Microbubbles effectively buffer frost heave stress, and the grout's rheological properties adapt to construction on steep longitudinal slopes, achieving a synergistic improvement in early strength, frost resistance, and anti-flow properties, significantly extending the service life of asphalt pavements in high-altitude mountainous areas.

[0021] This invention incorporates magnesium aluminum silicate and / or attapulgite thixotropic anti-flow agent into dry mixes. Utilizing the card-like spatial network formed during hydration and expansion, this imparts significant shear thinning and high static yield stress to the slurry. The low viscosity during mixing and transport facilitates handling, and the network rapidly rebuilds after disturbance ceases, effectively resisting gravity-induced plastic flow and ensuring retention and full filling in voids on extremely steep longitudinal slopes. Simultaneously, the thixotropic agent and fine powder synergistically enhance anti-segregation properties, prevent bleeding, and result in a uniform hardened slurry with strong interfacial bonding, significantly improving the overall load-bearing capacity and deformation resistance of the pavement structure.

[0022] This invention eliminates the problem of formulation infeasibility caused by mismatched lower limits by adjusting the lower limit of the air-entraining component to 0.05 parts by weight and limiting the amount of defoamer to 0.1-0.3 parts by weight, not exceeding twice the amount of air-entraining component, ensuring that the entire formulation range is feasible. The defoamer is added after a delayed addition process, stirring the mixture for 2-3 minutes before adding it. This ensures that the air-entraining agent fully foams to form a large number of microbubbles necessary for freeze protection, while the defoamer selectively eliminates large bubbles, precisely controlling the bubble structure. This achieves synergistic optimization of the freeze protection and mechanical strength of the hardened grout, giving the grouting material high reliability and durability under combined low-temperature and steep longitudinal slope conditions.

[0023] This invention utilizes the addition of rutile nano-titanium dioxide and / or ultrafine calcium carbonate as UV-resistant components in dry mixes. By leveraging their efficient UV absorption and scattering capabilities, it significantly reduces the irradiation degradation of organic components such as styrene-butadiene emulsions caused by strong ultraviolet radiation at high altitudes, delaying polymer photoaging and maintaining the flexibility and bonding strength of the grouting material. This effectively prevents surface powdering and cracking of the grout layer, blocks the intrusion of water and salts along microcracks, slows down freeze-thaw coupled aging damage, and allows the grouting material to maintain excellent service performance under long-term strong sunlight, reducing the frequency of maintenance and the total life-cycle cost of high-altitude road surfaces.

[0024] This invention introduces a silane coupling agent to construct a chemical bridge at the interface between inorganic fillers, cement hydration products, and styrene-butadiene emulsion polymers. This significantly enhances the interfacial bonding between the organic and inorganic phases, eliminates interfacial defects, and inhibits the initiation and propagation of microcracks. This results in a marked improvement in the flexural, compressive, and ultimate tensile strength of the grouting material. Especially under the intense temperature fluctuations and freeze-thaw stresses of high-altitude areas, the overall interfacial integrity is maintained, and the impermeability and erosion resistance are enhanced, ensuring the long-term safe service of the pavement grouting structure in harsh environments.

[0025] This invention utilizes hydroxypropyl methylcellulose ether and / or sorbent as foam-stabilizing components. By leveraging their high molecular weight long chains to thicken and enhance the elasticity of the bubble film, they inhibit the drainage and aggregation of microbubbles, preventing bubbles from escaping during stirring, transportation, and grouting. After hardening, a uniform, fine, and closed pore system is formed, providing ample pressure relief space for freeze-thaw cycles, significantly improving freeze-thaw resistance. Simultaneously, it avoids fluctuations in gas content and strength dispersion caused by bubble instability, ensuring the performance stability and construction reliability of the grouting material in low-temperature environments.

[0026] This invention premixes a thixotropic anti-flow agent with an equal mass of fly ash to form a thixotropic agent premix. Utilizing the dispersion and carrying capacity of fly ash microspheres, a very small amount of thixotropic agent particles are highly uniformly distributed in the dry mix, overcoming the agglomeration and unevenness problems associated with direct dry mixing. Upon contact with water, the thixotropic agent rapidly and uniformly forms a three-dimensional network, giving the grout a uniform anti-flow and thixotropic property, avoiding grouting defects caused by localized flow or excessive viscosity, ensuring dense filling of all parts of the slope, and improving the consistency of construction quality and the integrity of the pavement structure.

[0027] This invention pre-disperses the UV-resistant aging-resistant component by adding it to a styrene-butadiene emulsion and stirring at a high speed of 300-500 r / min. Utilizing the wetting and dispersing capabilities of the polymer emulsion, uniform pre-dispersion and surface coating of nanoparticles within the organic matrix are achieved, effectively breaking up agglomeration. This is then compounded with the remaining mixture, ensuring excellent dispersion of the UV-resistant component in the grout and its tight bonding with the polymer matrix. This maximizes UV shielding effectiveness, delays polymer photo-oxidative degradation, and enhances the nano-reinforcing effect, ensuring the grouting material maintains high adhesion and flexibility under strong UV radiation for extended periods.

[0028] This invention ensures that the UV-resistant components have a size comparable to the wavelength of ultraviolet light by limiting the primary particle size of rutile nano-titanium dioxide to 15–80 nm and the median particle size (D50) of ultrafine calcium carbonate to 0.5–3 μm. This avoids excessively small particle sizes leading to severe agglomeration or excessively large particle sizes causing reduced shielding efficiency and dispersion difficulties. Particles within this size range disperse well in the slurry without significant thickening, ensuring workability and providing stable UV resistance. This provides long-term protection for the internal polymer, enabling the grouting material to maintain both durability and mechanical properties even in high-altitude, high-UV environments.

[0029] Other advantages, objectives, and features of embodiments of the present invention will be apparent in part from the following description, and in part will be understood by those skilled in the art through study and practice of embodiments of the present invention. Detailed Implementation

[0030] To further illustrate the technical means and effects of this invention, the following description, in conjunction with embodiments, further explains the invention. The specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0031] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0032] According to an embodiment of the present invention, a method for preparing a grouting material includes the following steps: 1) Add 40-55 parts by weight of sulfoaluminate cement, 5-10 parts by weight of silica fume, 10-18 parts by weight of fly ash, 3-6 parts by weight of expansive agent, and 0.02-0.15 parts by weight of air-entraining component into a mixer and dry mix at a speed of 60-100 r / min for 2-4 minutes to obtain a dry mix; the air-entraining component is rosin thermal polymer and / or triterpenoid saponin air-entraining agent; 2) Based on the total weight of sulfoaluminate cement, silica fume, fly ash and expansive agent described in step 1) as 100 parts by weight, dissolve 0.3 to 0.8 parts by weight of polycarboxylate superplasticizer and 0.5 to 1.5 parts by weight of ethylene glycol antifreeze component in 25 to 35 parts by weight of water, then add 8 to 15 parts by weight of styrene-butadiene emulsion, and stir evenly to obtain a mixture. 3) Under continuous stirring, add the mixture obtained in step 2) to the dry mixture obtained in step 1) in 2 to 3 portions, with an interval of 30 to 60 seconds between each addition. After all the mixture is added, continue stirring for 3 to 5 minutes to obtain the grouting material.

[0033] A specific embodiment is as follows: 48 parts by weight of sulfoaluminate cement, 8 parts by weight of silica fume, 14 parts by weight of fly ash, 5 parts by weight of expanding agent, and 0.08 parts by weight of rosin thermal polymer air-entraining component are added to a mixer and dry-mixed at 80 rpm for 3 minutes to obtain a dry mix. Subsequently, 0.5 parts by weight of polycarboxylate superplasticizer and 1.0 part by weight of ethylene glycol-based antifreeze component are dissolved in 30 parts by weight of water, and then 12 parts by weight of styrene-butadiene emulsion are added and stirred evenly to prepare a mixture. Under the condition of continuous stirring of the dry mix, the mixture is added in three portions, with an interval of about 45 seconds between each addition. After all the mixture has been added, stirring is continued for 4 minutes to obtain the grouting material.

[0034] As a comparative example, an equal amount of ordinary Portland cement can be used to completely replace sulfoaluminate cement, while other components and processes remain unchanged. Compared with the closest existing technology, ordinary Portland cement-based grout, this comparative example exhibits extremely slow setting and hardening at low temperatures, resulting in severely insufficient early strength development and necessitating prolonged sealing and curing after pavement repair. Under freeze-thaw cycles, the lack of a uniform microbubble system means that the expansion pressure generated by the freezing of water within the capillaries easily triggers matrix cracking and surface spalling. Furthermore, the comparative example grout lacks appropriate thixotropic properties, leading to significant creep flow along the slope direction during asphalt pavement grouting on steep longitudinal slopes. This results in incomplete filling of upper voids and accumulation at the bottom, failing to form a continuous and dense load-bearing structure, thus inducing reflective cracking and interfacial delamination.

[0035] This implementation scheme effectively overcomes the aforementioned defects through the synergy of multiple components and a staged mixing process. The low-temperature, rapid-hardening characteristics of sulfoaluminate cement allow the slurry to complete the hydration reaction quickly even in cold environments, rapidly establishing skeletal strength and significantly shortening the curing time required for opening to traffic. Rosin thermal polymers or triterpenoid saponins, as air-entraining components, form numerous small, uniformly distributed, and stable closed pores during the staged addition and mixing process. These pores provide pressure relief space for ice crystal growth, significantly mitigating the internal stress generated by freeze-thaw cycles. Ethylene glycol-based antifreeze components lower the freezing point of the liquid phase, ensuring continuous hydration under sub-zero temperatures, further promoting early strength growth and stabilizing the bubble system. Styrene-butadiene emulsion forms an organic-inorganic interpenetrating network between the cement hydration products and aggregates, improving matrix toughness and interfacial bonding strength, inhibiting microcrack propagation, and endowing the slurry with suitable cohesiveness and anti-segregation ability. The process of adding the liquid mixture to the dry mix in two or three stages with controlled intervals ensures that each functional component is fully wetted, dispersed, and reacted. This avoids uneven local concentrations or the incorporation of large air bubbles during mixing, resulting in a homogeneous grouting material with a controllable microbubble structure even under low-temperature mixing conditions. When used for semi-flexible pavement or repair work in high-altitude, high-temperature-difference, and frequently freeze-thawed road sections, this grouting material exhibits excellent low-temperature early strength performance, high freeze-thaw resistance, and good resistance to slope runoff. This results in a full and dense grout layer that bonds tightly to the existing pavement, significantly extending the service life of the pavement structure under harsh operating conditions.

[0036] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, in step 1), based on 100 parts by weight of sulfoaluminate cement, silica fume, fly ash and expansion agent, 0.05 to 0.5 parts by weight of a thixotropic anti-flowing agent is added, wherein the thixotropic anti-flowing agent is magnesium aluminum silicate and / or attapulgite, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0037] A specific embodiment is as follows: 45 parts by weight of sulfoaluminate cement, 7 parts by weight of silica fume, 16 parts by weight of fly ash, 4 parts by weight of expansive agent, 0.06 parts by weight of triterpenoid saponin air-entraining component, and 0.2 parts by weight of magnesium aluminum silicate thixotropic anti-flow agent are added to a mixer and dry-mixed at 90 rpm for 3 minutes to obtain a dry mix. Then, 0.6 parts by weight of polycarboxylate superplasticizer and 0.8 parts by weight of ethylene glycol-based antifreeze component are dissolved in 28 parts by weight of water, and then 10 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. While continuously stirring, the mixture is added to the dry mix in two batches, with a 40-second interval between each addition. After each addition, stirring continues for 4 minutes to obtain the grouting material.

[0038] This implementation scheme fundamentally alters the rheological behavior of the slurry by introducing magnesium aluminum silicate and / or attapulgite thixotropic anti-flow agents. These layered silicate minerals rapidly expand upon contact with water and cleave into charged micro-lamellae. These lamellars interlock through end-to-face or end-to-end electrostatic interactions, forming a continuous three-dimensional card-like spatial network within the slurry. This network endows the slurry with significant shear-thinning properties and high static yield stress. During mixing, pumping, and grouting, mechanical shear forces disrupt the network structure, causing a sharp decrease in slurry viscosity and excellent fluidity, allowing it to easily penetrate and fill micro-voids. Once the slurry stops being disturbed and has filled the voids, the shear force is removed, the electrostatic connections between the lamellars are rebuilt in a very short time, the spatial network rapidly recovers, and the slurry yield stress rises significantly, sufficient to resist the component of its own weight along the slope direction, thus firmly anchoring it at the grouting location and preventing further downward flow. Meanwhile, the thixotropic network construction uniformly binds the powder particles and hydration products, significantly inhibiting aggregate settling and free water secretion, avoiding bleeding and segregation, and ensuring the uniformity and density of the hardened grout in all parts of the slope. Ultimately, the grout layer on the slope is full, uniform, and continuous, achieving tight interlocking and full bonding with the original asphalt mixture aggregate, with no voids or stress concentrations at the interface. The overall load-bearing capacity and deformation resistance of the composite pavement structure are significantly enhanced, and its service life is effectively extended.

[0039] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, the amount of the air-entraining component added is 0.05 to 0.15 parts by weight; based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expanding agent in step 1), the grouting material further contains 0.1 to 0.3 parts by weight of defoamer, the defoamer being a mineral oil-based defoamer and / or a polyether-modified organosilicon defoamer, and the amount of the defoamer added is not greater than twice the amount of the air-entraining component added; wherein, in step 3), the mixture obtained in step 2) is added to the dry mixture obtained in step 1) in 2 to 3 portions and stirred for 2 to 3 minutes, then the defoamer is added, and stirring is continued for another 1 to 2 minutes.

[0040] A specific embodiment is as follows: 50 parts by weight of sulfoaluminate cement, 9 parts by weight of silica fume, 12 parts by weight of fly ash, 6 parts by weight of expanding agent, and 0.10 parts by weight of rosin thermal polymer air-entraining component are added to a mixer and dry-mixed at 70 rpm for 2 minutes to obtain a dry mix. Then, 0.4 parts by weight of polycarboxylate superplasticizer and 1.2 parts by weight of ethylene glycol-based antifreeze component are dissolved in 32 parts by weight of water, and 14 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. Under continuous stirring, the mixture is added to the dry mix in three portions, with a 50-second interval between each addition. After each addition, stirring continues. After stirring for 2.5 minutes, 0.2 parts by weight of mineral oil-based defoamer is added, and stirring continues for another 1.5 minutes to obtain the grouting material.

[0041] Under low temperature and freeze-thaw alternating service conditions, the mechanical properties and freeze-thaw resistance of the grouting material are synergistically optimized, resulting in a significant improvement in reliability and service life.

[0042] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, in step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent, 1.5 to 4 parts by weight of a UV-resistant aging component is added, wherein the UV-resistant aging component is rutile nano-titanium dioxide and / or ultrafine calcium carbonate, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0043] A specific embodiment is as follows: 42 parts by weight of sulfoaluminate cement, 10 parts by weight of silica fume, 15 parts by weight of fly ash, 5 parts by weight of expanding agent, 0.07 parts by weight of triterpenoid saponin air-entraining component, and 2.5 parts by weight of rutile nano-titanium dioxide are added to a mixer and dry-mixed at 85 rpm for 4 minutes to obtain a dry mix. 0.7 parts by weight of polycarboxylate superplasticizer and 0.6 parts by weight of ethylene glycol antifreeze component are dissolved in 27 parts by weight of water, and then 11 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. Under stirring conditions, the mixture is added to the dry mix in two batches, with an interval of 45 seconds between each addition. After each addition, stirring is continued for 3 minutes to obtain the grouting material.

[0044] In high-altitude road sections with strong sunlight and large temperature differences, this grouting material can maintain good integrity and adhesion for a long time, significantly reducing the risk of grout layer failure and early road surface damage, and reducing the frequency of maintenance and repair and the total life cycle cost.

[0045] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, in step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expanding agent, 0.3 to 1.0 parts by weight of a silane coupling agent is added, wherein the silane coupling agent is γ-aminopropyltriethoxysilane and / or γ-glycidoxypropyltrimethoxysilane, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0046] A specific embodiment is as follows: 43 parts by weight of sulfoaluminate cement, 8 parts by weight of silica fume, 17 parts by weight of fly ash, 5 parts by weight of expansive agent, 0.09 parts by weight of rosin thermal polymer air-entraining component, and 0.6 parts by weight of γ-aminopropyltriethoxysilane coupling agent are added to a mixer and dry-mixed at 75 rpm for 3 minutes to obtain a dry mix. 0.5 parts by weight of polycarboxylate superplasticizer and 1.1 parts by weight of ethylene glycol-based antifreeze component are dissolved in 30 parts by weight of water, and then 13 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. Under continuous stirring, the mixture is added to the dry mix in three portions, with an interval of 35 seconds between each addition. After all the mixture is added, stirring is continued for 5 minutes to obtain the grouting material.

[0047] In the harsh service environment of the plateau, the integrity of the interface is maintained for a long time, and the ability to resist impermeability and the intrusion of corrosive media are enhanced simultaneously, thus effectively ensuring the integrity of the grouting layer and the safe service life of the pavement structure.

[0048] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, in step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent, 0.01 to 0.05 parts by weight of a foam stabilizing component is added, wherein the foam stabilizing component is hydroxypropyl methylcellulose ether and / or styrene ether, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

[0049] A specific embodiment is as follows: 46 parts by weight of sulfoaluminate cement, 6 parts by weight of silica fume, 18 parts by weight of fly ash, 4 parts by weight of expansive agent, 0.12 parts by weight of triterpenoid saponin air-entraining component, and 0.03 parts by weight of hydroxypropyl methylcellulose ether foam stabilizer are added to a mixer and dry-mixed at 80 rpm for 2.5 minutes to obtain a dry mix. 0.6 parts by weight of polycarboxylate superplasticizer and 0.9 parts by weight of ethylene glycol antifreeze component are dissolved in 29 parts by weight of water, and then 9 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. Under continuous stirring, the mixture is added to the dry mix in two batches, with an interval of 55 seconds between each addition. After each addition, stirring is continued for 3 minutes to obtain the grouting material.

[0050] This grouting material can withstand repeated freeze-thaw cycles for a long time under low temperature and large temperature difference service conditions, maintaining structural density and strength stability, thus improving both construction quality reliability and structural durability.

[0051] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, in step 1), the thixotropic anti-flowing agent is premixed with an equal mass of fly ash to obtain a thixotropic agent premix, and then the thixotropic agent premix and the remaining dry mix are put into a mixer for dry mixing.

[0052] A specific embodiment is as follows: 0.3 parts by weight of attapulgite thixotropic anti-flow agent and 0.3 parts by weight of fly ash are pre-mixed by hand in a small container to prepare a thixotropic agent premix. Then, 47 parts by weight of sulfoaluminate cement, 9 parts by weight of silica fume, the remaining 13.7 parts by weight of fly ash, 5 parts by weight of expansive agent, 0.05 parts by weight of rosin thermal polymer air-entraining component, and the above-mentioned thixotropic agent premix are added to a mixer and dry-mixed at 65 rpm for 4 minutes to obtain a dry mix. 0.4 parts by weight of polycarboxylate superplasticizer and 1.3 parts by weight of ethylene glycol-based antifreeze component are dissolved in 31 parts by weight of water, and then 15 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. While continuously stirring, the mixture is added to the dry mix in three portions, each 45 seconds apart. After all the mixture is added, stirring continues for 3 minutes to obtain the grouting material.

[0053] During grouting, the grout exhibits uniform resistance to flow across the slope, preventing localized slippage or blockage, and ensuring full and continuous filling of voids. The uniform thixotropic network construction also avoids uneven mixing and clumping caused by excessive local thickening, improving the overall homogeneity and workability of the grout. After hardening, the grout layer exhibits highly uniform strength and density across all parts, with no weak points in the interfacial bond with the asphalt mixture, thus comprehensively ensuring the uniformity of load-bearing capacity and the long-term integrity of the pavement composite structure.

[0054] According to one embodiment of the present invention, a method for preparing a grouting material, preferably, based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent described in step 1), the grouting material further contains 1.5 to 4 parts by weight of a UV-resistant aging component, wherein the UV-resistant aging component is rutile nano-titanium dioxide and / or ultrafine calcium carbonate; wherein, in step 2), the UV-resistant aging component is first added to the styrene-butadiene emulsion and stirred and dispersed at a speed of 300 to 500 r / min for 5 to 10 minutes to obtain a UV-resistant component-polymer premix, and then the UV-resistant component-polymer premix is ​​added to the mixture described in step 2) and stirred evenly.

[0055] A specific embodiment is as follows: 40 parts by weight of sulfoaluminate cement, 10 parts by weight of silica fume, 18 parts by weight of fly ash, 6 parts by weight of expanding agent, and 0.06 parts by weight of triterpenoid saponin air-entraining component are added to a mixer and dry-mixed at 90 rpm for 2.5 minutes to obtain a dry mix. 2 parts by weight of rutile nano-titanium dioxide are added to 13 parts by weight of styrene-butadiene emulsion and dispersed at high speed of 400 rpm for 8 minutes to obtain an aging-resistant component-polymer premix. 0.5 parts by weight of polycarboxylate superplasticizer and 1.2 parts by weight of ethylene glycol-based antifreeze component are dissolved in 30 parts by weight of water and stirred evenly. Then, the above premix is ​​added to the water and stirred evenly to obtain a mixture. Under continuous stirring, the mixture is added to the dry mix in two batches, with an interval of 40 seconds between each addition. After all the mixture is added, it is stirred for another 3.5 minutes to obtain the grouting material.

[0056] This grouting material maintains its flexibility and adhesion under high-altitude and strong sunlight conditions for a long time. It has excellent resistance to surface powdering and cracking, and the destructive process of freeze-thaw and UV coupled aging is significantly inhibited.

[0057] According to one embodiment of the present invention, a method for preparing a grouting material is preferred, wherein the primary particle size of the rutile nano-titanium dioxide is 15-80 nm, and the median particle size D50 of the ultrafine calcium carbonate is 0.5-3 μm.

[0058] A specific embodiment is as follows: 52 parts by weight of sulfoaluminate cement, 5 parts by weight of silica fume, 10 parts by weight of fly ash, 4 parts by weight of expansive agent, 0.10 parts by weight of rosin thermal polymer air-entraining component, and 3.5 parts by weight of ultrafine calcium carbonate are added to a mixer and dry-mixed at 85 rpm for 3.5 minutes to obtain a dry mix. The median particle size D50 of the selected ultrafine calcium carbonate is 1.8 micrometers. 0.7 parts by weight of polycarboxylate superplasticizer and 0.5 parts by weight of ethylene glycol-based antifreeze component are dissolved in 28 parts by weight of water, and then 8 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. Under continuous stirring, the mixture is added to the dry mix in three portions, with an interval of 35 seconds between each addition. After each addition, the mixture is stirred for another 4 minutes to obtain the grouting material.

[0059] When grouting materials are in harsh environments with high altitude, strong ultraviolet radiation, large temperature differences, and repeated freeze-thaw cycles, the uniformly dispersed ultraviolet-resistant particles form a three-dimensional light-shielding network in the matrix, ensuring the structural and performance stability of the polymer organic phase throughout its service life. The grouting layer surface does not crack or pulverize for a long time, and the bonding strength with the road surface remains high, resulting in a fundamental improvement in overall durability.

[0060] According to one embodiment of the present invention, a grouting material is provided, which is prepared by any of the methods described herein.

[0061] A specific embodiment is as follows: 44 parts by weight of sulfoaluminate cement, 7 parts by weight of silica fume, 13 parts by weight of fly ash, 5 parts by weight of expansive agent, 0.09 parts by weight of rosin thermal polymer air-entraining component, and 0.15 parts by weight of attapulgite thixotropic anti-flow agent are added to a mixer and dry-mixed at 80 rpm for 3 minutes to obtain a dry mix. 0.5 parts by weight of polycarboxylate superplasticizer and 1.0 part by weight of ethylene glycol-based antifreeze component are dissolved in 31 parts by weight of water, and then 11 parts by weight of styrene-butadiene emulsion are added and stirred evenly to obtain a mixture. Under continuous stirring, the mixture is added to the dry mix in three portions, with an interval of 45 seconds between each addition. After each addition, stirring is continued for 3 minutes to obtain a grouting material.

[0062] The sulfoaluminate cement is a rapid-hardening sulfoaluminate cement with a strength grade of not less than 42.5. The expansive agent is a calcium sulfoaluminate-based concrete expansive agent. The styrene-butadiene emulsion is a styrene-butadiene polymer emulsion with a solid content of 45% ± 2% and a pH value of 8–10. The ethylene glycol-based antifreeze component is ethylene glycol (chemically pure, purity ≥ 99.5%). The polycarboxylate superplasticizer is a high-performance polycarboxylate superplasticizer. The hydroxypropyl methylcellulose ether (HPMC) has a viscosity grade of 4000 mPa·s (2% aqueous solution, 20℃), a methoxy content of 19%–24%, and a hydroxypropoxy content of 4%–12%. The magnesium aluminum silicate has a montmorillonite content ≥ 95% and a gel value ≥ 3.5 mL / g; the attapulgite clay has a viscosity (12% aqueous solution, 60 r / min) ≥ 400 mPa·s and a moisture content ≤ 15%.

[0063] The grouting material prepared according to this implementation plan achieves a comprehensive performance improvement over existing grouting materials through the synergistic effect of a low-temperature rapid-hardening cementitious system of sulfoaluminate cement, finely graded silica fume and fly ash, a controllable micro-air-entraining system, ethylene glycol-based antifreeze components, and styrene-butadiene emulsion polymer toughening, as well as process control using staged liquid addition and stirring. This grouting material can rapidly hydrate and harden under low-temperature conditions, establishing sufficient mechanical strength to withstand construction vehicles and temporary loads within hours, significantly shortening road closure and maintenance time. The hardened grout contains a large number of small, rationally spaced, closed, and independent microbubbles. These bubbles provide ample pressure relief space for ice expansion during freeze-thaw cycles, ensuring that the frost heave tensile stress on the matrix remains below the material's tensile limit. Therefore, it possesses extremely high freeze-thaw resistance, maintaining structural integrity and strength stability even under frequent freeze-thaw cycles year after year. The grout exhibits significant shear-thinning properties and excellent static yield stress. During injection, it flows well and penetrates into micro-pores. After disturbance ceases, the thixotropic network rapidly rebuilds, resisting the component of gravity along the longitudinal slope and remaining firmly in place at the injection site, forming a continuous, full, and homogeneous filler from top to bottom. An interpenetrating network forms between the organic polymer and inorganic hydration products, resulting in interfacial reinforcement. The material possesses both high compressive strength and high flexural toughness, exhibiting strong adhesion to the existing asphalt pavement and capable of withstanding repeated heavy traffic loads. In high-altitude environments with strong ultraviolet radiation, the uniform pre-dispersion and optimized particle size of the UV-resistant components within the polymer matrix ensure long-term UV shielding effectiveness. Photodegradation of the polymer molecular chains is effectively delayed, and the flexibility, adhesion, and resistance to surface chalking of the grout layer remain consistently strong. In summary, this grouting material integrates several key properties, including low-temperature early strength, high freeze-thaw resistance, anti-flow on steep longitudinal slopes, and strong UV durability. It solves several core problems faced by road grouting in high-altitude mountainous areas in a single material, significantly improving the construction quality, service reliability, and long-term service life of grouting repair projects, while reducing the frequency of maintenance and repair and the total life cycle cost during the road's operation period.

[0064] According to one embodiment of the present invention, a method for preparing a grouting material involves pre-mixing 0.25 kg of attapulgite thixotropic anti-flow agent and 0.25 kg of fly ash by hand to obtain a thixotropic agent premix. Then, 50 kg of sulfoaluminate cement, 8 kg of silica fume, 12.75 kg of fly ash, 4 kg of expanding agent, 0.12 kg of triterpenoid saponin air-entraining component, 0.03 kg of warm-rolled colloid foam stabilizer, 0.7 kg of γ-glycidyl etheroxypropyltrimethoxysilane coupling agent, and the aforementioned thixotropic agent premix are added to a mixer and dry-mixed at 80 rpm for 3 minutes to obtain a dry mix.

[0065] 2.5 kg of rutile nano-titanium dioxide with a native particle size of 25 nm was added to 12 kg of styrene-butadiene emulsion and dispersed by high-speed stirring at 450 rpm for 6 minutes to obtain an anti-aging component-polymer premix. 0.5 kg of polycarboxylate superplasticizer and 1.0 kg of ethylene glycol-based antifreeze were dissolved in 30 kg of water and stirred until homogeneous. The anti-aging component-polymer premix was then added to the solution and stirred until homogeneous to obtain a mixed solution.

[0066] Under continuous stirring, the mixture is added to the dry mix in three portions, with a 45-second interval between each addition. After all the mixture is added, stirring is continued for 2.5 minutes. At this point, 0.2 kg of polyether-modified silicone defoamer is added, and stirring is continued for another 1.5 minutes to obtain the grouting material.

[0067] This grouting material exhibits excellent early strength at -5℃: the compressive strength reaches 5.2 MPa and the flexural strength 1.4 MPa after 2 hours; the compressive strength further increases to 52.3 MPa and the flexural strength to 8.9 MPa after 28 days. After 300 freeze-thaw cycles, the mass loss rate of the grouting material is only 1.6%, the compressive strength loss rate is 9.8%, the relative dynamic modulus of elasticity remains at 91.2%, and the air content of the fresh grout is 4.5%. Under test conditions of a 15° slope and a 30-minute settling period, the grouting material has a flow distance of 3.8 cm, a yield stress of 46.5 Pa, and a thixotropic index (recovery rate) of 78%, indicating that it possesses excellent anti-gravity flow ability while ensuring good construction flowability, and can meet the grouting requirements of ultra-sloping pavements. This embodiment achieves optimal levels in terms of low-temperature early strength, freeze-thaw resistance, anti-flow, UV aging resistance, and workability, and is particularly suitable for the harsh grouting conditions of ultra-sloping asphalt pavements in high-altitude mountainous areas.

[0068] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for embodiments of the present invention. Other modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the embodiments of the present invention are not limited to the specific details.

Claims

1. A method for preparing a grouting material, characterized in that, Includes the following steps: 1) Add 40-55 parts by weight of sulfoaluminate cement, 5-10 parts by weight of silica fume, 10-18 parts by weight of fly ash, 3-6 parts by weight of expansive agent, and 0.02-0.15 parts by weight of air-entraining component into a mixer and dry mix at a speed of 60-100 r / min for 2-4 minutes to obtain a dry mix; the air-entraining component is rosin thermal polymer and / or triterpenoid saponin air-entraining agent; 2) Based on the total weight of sulfoaluminate cement, silica fume, fly ash and expansive agent described in step 1) as 100 parts by weight, dissolve 0.3 to 0.8 parts by weight of polycarboxylate superplasticizer and 0.5 to 1.5 parts by weight of ethylene glycol antifreeze component in 25 to 35 parts by weight of water, then add 8 to 15 parts by weight of styrene-butadiene emulsion, and stir evenly to obtain a mixture. 3) Under continuous stirring, add the mixture obtained in step 2) to the dry mixture obtained in step 1) in 2 to 3 portions, with an interval of 30 to 60 seconds between each addition. After all the mixture is added, continue stirring for 3 to 5 minutes to obtain the grouting material.

2. The method for preparing the grouting material as described in claim 1, characterized in that, In step 1), based on 100 parts by weight of sulfoaluminate cement, silica fume, fly ash and expansive agent, 0.05 to 0.5 parts by weight of thixotropic anti-flowing agent are added. The thixotropic anti-flowing agent is magnesium aluminum silicate and / or attapulgite. The dry mixture is then dry-mixed with the remaining dry mix to obtain the dry mix.

3. The method for preparing the grouting material as described in claim 1, characterized in that, The amount of the air-entraining component added is 0.05 to 0.15 parts by weight; based on the total weight of sulfoaluminate cement, silica fume, fly ash and expansion agent in step 1) as 100 parts by weight, the grouting material also contains 0.1 to 0.3 parts by weight of defoamer, the defoamer is a mineral oil-based defoamer and / or a polyether-modified organosilicon defoamer, and the amount of defoamer added is not more than twice the amount of the air-entraining component added; wherein, in step 3), the mixture obtained in step 2) is added to the dry mixture obtained in step 1) in 2 to 3 portions and stirred for 2 to 3 minutes, then the defoamer is added, and stirring is continued for 1 to 2 minutes.

4. The method for preparing the grouting material as described in claim 1, characterized in that, In step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansion agent, 1.5 to 4 parts by weight of a UV-resistant aging component is added. The UV-resistant aging component is rutile nano-titanium dioxide and / or ultrafine calcium carbonate. The dry mixture is then dry-mixed with the remaining dry mixture to obtain the dry mixture.

5. The method for preparing the grouting material as described in claim 1, characterized in that, In step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansive agent, 0.3 to 1.0 parts by weight of a silane coupling agent is added. The silane coupling agent is γ-aminopropyltriethoxysilane and / or γ-glycidoxypropyltrimethoxysilane. The silane coupling agent is then dry-mixed with the remaining dry mix to obtain the dry mix.

6. The method for preparing the grouting material as described in claim 1, characterized in that, In step 1), based on 100 parts by weight of the total weight of the sulfoaluminate cement, silica fume, fly ash and expansive agent, 0.01 to 0.05 parts by weight of a foam stabilizing component is added, wherein the foam stabilizing component is hydroxypropyl methylcellulose ether and / or styrene ether, and is dry-mixed together with the remaining dry mix to obtain the dry mix.

7. The method for preparing the grouting material as described in claim 2, characterized in that, In step 1), the thixotropic anti-flowing agent is premixed with an equal mass of fly ash to obtain a thixotropic agent premix, and then the thixotropic agent premix and the remaining dry mix are put into a mixer for dry mixing.

8. The method for preparing the grouting material as described in claim 1 or 2, characterized in that, Based on 100 parts by weight of the total weight of sulfoaluminate cement, silica fume, fly ash and expansion agent mentioned in step 1), the grouting material also contains 1.5 to 4 parts by weight of UV-resistant aging component, which is rutile nano-titanium dioxide and / or ultrafine calcium carbonate; wherein, in step 2), the UV-resistant aging component is first added to the styrene-butadiene emulsion and stirred and dispersed at a speed of 300 to 500 r / min for 5 to 10 minutes to obtain the aging-resistant component-polymer premix, and then the aging-resistant component-polymer premix is ​​added to the mixture in step 2) and stirred evenly.

9. The method for preparing the grouting material as described in claim 4 or 8, characterized in that, The original particle size of the rutile nano-titanium dioxide is 15-80 nm, and the median particle size D50 of the ultrafine calcium carbonate is 0.5-3 μm.

10. A grouting material, characterized in that, It is prepared by the method of any one of claims 1 to 9.