Road ditch self-leveling mortar and preparation method thereof

Abstract

The application relates to the technical field of highway maintenance, in particular to a highway drainage ditch self-leveling mortar and a preparation method thereof. The highway drainage ditch self-leveling mortar is prepared from at least gelatinous material and 20-200 mesh graded aggregate, the mass ratio of the gelatinous material and the graded aggregate is (14-17):(9-12), and a composite reinforcing agent and a functional additive are further added. The application greatly improves the core contradiction that the self-leveling performance and the structural durability cannot be simultaneously considered in the construction of the highway drainage ditch, the prepared mortar has excellent fluidity and thixotropy in the construction, can automatically flow and evenly cover on the inclined ditch wall, effectively avoids defects caused by manual troweling, greatly improves the construction efficiency and the forming quality, and the structure formed after hardening is compact and has a self-reinforcing characteristic.

Description

Technical Field

[0001] This invention relates to the field of highway maintenance technology, and in particular to a self-leveling mortar for highway drainage ditches and its preparation method. Background Technology

[0002] In highway construction, drainage systems are a crucial component ensuring road structural durability and driving safety. Drainage ditches, as the primary channels for rainwater and surface water, are directly affected by their construction quality and material properties, impacting the overall efficiency and lifespan of the drainage system. Traditional highway drainage ditches often utilize cast-in-place or precast concrete components, which, while possessing certain strength and durability, have revealed numerous problems in practical applications, such as long construction periods, proneness to leakage at joints, poor surface smoothness, and insufficient erosion resistance. To address these shortcomings, in recent years, the engineering community has gradually introduced new materials such as polymer-modified mortar and self-compacting concrete for the repair and construction of drainage ditches, aiming to improve overall performance.

[0003] Self-leveling mortar, a building material with high fluidity, self-compacting properties, and good construction adaptability, has been widely used in flooring, bridge repair, and tunnel lining. It achieves its ability to automatically level and fill complex spaces without vibration by optimizing the cementitious material system and incorporating high-efficiency water-reducing agents and mineral admixtures, while also possessing high early strength and volume stability. Given these advantages, some studies have explored the application of self-leveling mortar in the on-site casting or partial repair of highway drainage ditches, hoping to improve the integrity and waterproofing performance of the ditch by leveraging its excellent fluidity and compactness. Furthermore, some patent documents have disclosed fast-setting or erosion-resistant self-leveling mortar formulations specifically for drainage ditches, emphasizing their adhesion and durability performance in humid environments.

[0004] Although existing self-leveling mortar technology is relatively mature in the general construction field, there are still obvious technical problems in its direct application to highway drainage ditches. For example, conventional self-leveling mortar is difficult to apply to drainage ditches, which usually have sloping or even curved structures. Under the action of gravity, the mortar is prone to flow, segregation, or uneven accumulation, making it difficult to ensure uniform coverage and structural integrity of the bottom and sidewalls of the ditch. Moreover, highway drainage ditches are subjected to harsh service environments such as alternating wet and dry conditions, water scouring, and freeze-thaw cycles. Ordinary self-leveling mortar often lacks sufficient resistance to scouring, cracking, and chemical corrosion, leading to powdering, peeling, or even structural damage to the ditch surface. Summary of the Invention

[0005] Therefore, how to prepare a self-leveling mortar specifically suitable for highway drainage ditch conditions, and effectively solve key technical problems such as poor slope construction stability, insufficient durability and weak environmental adaptability while maintaining good fluidity and self-compacting properties, has become an important issue for those skilled in the art.

[0006] This invention application provides a self-leveling mortar for highway drainage ditches, the raw materials of which include at least a gel material and graded aggregate of 20-200 mesh, and the mass ratio of gel material to graded aggregate is (14-17):(9-12), as well as a composite reinforcing agent and functional additives.

[0007] In a preferred embodiment, the gel material is a combination of cementitious material, slag powder, and silica fume.

[0008] In a preferred embodiment, the mass ratio of the cementitious material, slag powder and silica fume is (9~11):(2~3.5):(0.5~1.2).

[0009] A more preferred embodiment is that the mass ratio of the cementitious material, slag powder and silica fume is (9.5~10.5):(2.5~3):(0.7~0.9).

[0010] In a preferred embodiment, the cement material is silicate cement or ordinary silicate cement.

[0011] A more preferred embodiment is that the cement material is silicate cement.

[0012] In a preferred embodiment, the strength grade of the cement material is 52.5 or 52.5R.

[0013] In a preferred embodiment, the slag powder is blast furnace slag powder.

[0014] In a preferred embodiment, the blast furnace slag powder is at least one of S75, S95 and S105 grades.

[0015] In a more preferred embodiment, the blast furnace slag powder is of grade S95 or S105.

[0016] In a more preferred embodiment, the blast furnace slag powder is of grade S95.

[0017] In a preferred embodiment, the graded aggregate is a combination of 40-70 mesh dry quartz sand and 100-140 mesh dry quartz sand.

[0018] In a preferred embodiment, the mass ratio of the 40-70 mesh dry quartz sand to the 100-140 mesh dry quartz sand is (6-7):(3-4).

[0019] A more preferred embodiment is that the mass ratio of the 40-70 mesh dry quartz sand to the 100-140 mesh dry quartz sand is (6-6.5):(3.5-4).

[0020] In a preferred embodiment, the mass ratio of the gel material, the composite reinforcing agent, and the functional additive is (14~17):(0.6~1):(0.4~1).

[0021] In a more preferred embodiment, the mass ratio of the gel material, the composite reinforcing agent, and the functional additive is (15~16.5):(0.8~0.9):(0.6~0.7).

[0022] In a preferred embodiment, the composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate.

[0023] In a preferred embodiment, the mass ratio of the glyceryl monostearate to sodium molybdate is (4~5):(1~2).

[0024] In a more preferred embodiment, the mass ratio of glyceryl monostearate to sodium molybdate is (4~4.5):(1.5~1.8).

[0025] The mortar system utilizes the controlled hydrolysis of glyceryl monostearate in the alkaline environment of the cement paste through the addition of glyceryl monostearate. The released stearate ions combine with calcium ions to form hydrophobic calcium stearate microcrystals in situ. These microcrystals preferentially grow and densely deposit in capillary pores and microcracks, achieving a dual effect of internal physical blockage of channels and long-lasting hydrophobicity of the pore walls. Simultaneously, the addition of sodium molybdate not only further stabilizes the hydration process, but its molybdate ions also optimize the morphology and distribution of hydration products. Furthermore, it works synergistically with precursors to form a protective interface between the pore fluid and the metal surface, thereby enhancing the overall structural integrity of the mortar in the face of water penetration, freeze-thaw cycles, and chemical erosion.

[0026] In a preferred embodiment, the functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate.

[0027] In a preferred embodiment, the mass ratio of tetrahydroxypropylethylenediamine to calcium nitrate is (0.5~1):(1.3~1.6).

[0028] In a more preferred embodiment, the mass ratio of tetrahydroxypropylethylenediamine to calcium nitrate is (0.7~0.9):(1.4~1.5).

[0029] The addition of tetrahydroxypropylethylenediamine preferentially complexes with calcium ions dissolved from the surface of cement particles in the early stage of hydration. This effectively delays the rapid generation and aggregation of hydration products in the early stage, thus providing a crucial fluidity maintenance stage for the mortar. Subsequently, the additional calcium ions and nitrate ions provided by calcium nitrate begin to dominate the process. They not only break the above complexation balance and promote further deep hydration of cement minerals, but more importantly, they synergize with the active components in the system to guide the generation of richer and finer hydrated calcium silicate gel and other products, comprehensively enhancing the various properties of the mortar.

[0030] A more preferred embodiment is that the self-leveling mortar for highway drainage ditches also includes rheology modifiers, strength modifiers, polymer modifiers, and defoamers in its raw materials.

[0031] In a preferred embodiment, the rheology modifier is a combination of polycarboxylate superplasticizer and hydroxypropyl methylcellulose ether.

[0032] In a preferred embodiment, the mass ratio of the polycarboxylate superplasticizer to hydroxypropyl methylcellulose ether is (1~2):(0.2~0.4).

[0033] A more preferred embodiment is that the mass ratio of the polycarboxylate superplasticizer to hydroxypropyl methylcellulose ether is (1.3~1.6):(0.25~0.35).

[0034] In a preferred embodiment, the strength modifier is a combination of calcium formate and tartaric acid.

[0035] In a preferred embodiment, the mass ratio of calcium formate to tartaric acid is (2~3):(0.5~1).

[0036] In a more preferred embodiment, the mass ratio of calcium formate to tartaric acid is (2.4~2.7):(0.6~0.8).

[0037] In a preferred embodiment, the polymer modifier is VAE polymer powder.

[0038] A more preferred embodiment is that the VAE polymer powder is specifically 5044N, manufactured by Wacker Chemie AG, Germany.

[0039] In a preferred embodiment, the defoamer is any one of the organosilicon defoamers.

[0040] A more preferred embodiment is that the self-leveling mortar for highway drainage ditches comprises, by weight, the following raw materials: 140-170 parts of gel material, 90-120 parts of graded aggregate, 1.2-2 parts of rheology modifier, 1.5-3 parts of strength modifier, 3-5 parts of polymer modifier, 6-10 parts of composite reinforcing agent, 0.2-0.3 parts of defoamer, and 4-10 parts of functional additives.

[0041] A method for preparing self-leveling mortar for highway drainage ditches includes the following steps: S1: Mixing water with all ingredients except composite reinforcing agents and functional additives at 300-400 rpm to prepare an aqueous solution, and then mixing the aqueous solution with the powdered raw materials prepared from the remaining raw materials and adding it to a high-speed mixer; S2: Continuously stirring at 600-800 rpm for 4-5 minutes in the high-speed mixer, and after completion, letting the resulting slurry stand for 10-15 minutes, and then stirring again at 500-700 rpm for 2-3 minutes, thus obtaining a castable self-leveling mortar for highway drainage ditches.

[0042] The beneficial effects of this application are:

[0043] 1. This invention, through a unique compound formulation, significantly improves the core contradiction in highway drainage ditch construction where self-leveling performance and structural durability are difficult to balance. This mortar exhibits excellent fluidity and thixotropy during construction, automatically leveling and evenly covering sloping ditch walls, effectively avoiding defects caused by manual smoothing, greatly improving construction efficiency and molding quality. Furthermore, the hardened structure is dense and self-reinforcing, capable of long-term resistance to rainwater erosion, freeze-thaw cycles, and load stress, significantly extending the service life of the drainage ditch, achieving a harmonious balance between convenient and efficient construction and long-term reliable service.

[0044] 2. This invention introduces specific composite additives to induce the in-situ generation of hydrophobic microcrystals in the mortar during the hardening process and optimize its microstructure. These microcrystals continuously and densely fill and seal capillary pores and microcracks, while simultaneously forming a stable protective interface with synergistic components within the matrix. This process fundamentally and significantly enhances the mortar's impermeability, resistance to freeze-thaw damage, and durability against chemical erosion, thereby ensuring the integrity and service life of highway drainage ditch structures under long-term harsh environments.

[0045] 3. This invention introduces a compound system of tetrahydroxypropylethylenediamine and calcium nitrate to ensure that the mixture can effectively maintain its fluid state after mixing, ensuring full and uniform self-leveling filling in complex trenches. This significantly reduces construction difficulty and eliminates the defects of manual smoothing. After leveling, the system quickly transforms and guides the deep hydration of cement, generating a richer and denser network of hydration products. This significantly improves the early strength development rate and overall density of the mortar, achieving a balance between ease of construction and high structural strength and durability. Detailed Implementation

[0046] Unless otherwise specified, some of the raw material sources / preparation methods in the specific embodiments of this application are as follows:

[0047] Cement material: Silicate cement P·II 52.5, Hubei Zhongnan Road & Bridge.

[0048] Blast furnace slag powder: S95 grade, Hebei Leijiang New Materials.

[0049] Graded aggregate: dried quartz sand, Hubei Zhongnan Road & Bridge.

[0050] Polycarboxylate superplasticizer: Industrial early-strength type, Shandong Jinan Qingtian Chemical Co., Ltd.

[0051] Polymer modifier: VAE polymer powder 5044N, Wacker Chemie, Germany.

[0052] Defoamer: Organosilicon defoamer BYK-028, BYK (Germany).

[0053] Example 1

[0054] A self-leveling mortar for highway drainage ditches, the raw materials, by weight, include: 155 parts of gel material, 110 parts of graded aggregate, 1.8 parts of rheology modifier, 2.3 parts of strength modifier, 4.2 parts of polymer modifier, 8.2 parts of composite reinforcing agent, 0.2 parts of defoamer, and 6.6 parts of functional additives.

[0055] The gelling material is a combination of silicate cement P·II 52.5, S95 grade blast furnace slag powder and silica fume, with a mass ratio of 10.5:2.7:0.8.

[0056] The graded aggregate is a combination of 40-70 mesh dry quartz sand and 100-140 mesh dry quartz sand in a mass ratio of 6.5:3.5.

[0057] The rheology modifier is a combination of polycarboxylate superplasticizer and hydroxypropyl methylcellulose ether in a mass ratio of 1.5:0.3.

[0058] The strength modifier is a combination of calcium formate and tartaric acid in a mass ratio of 2.7:0.8.

[0059] The polymer modifier is VAE polymer powder.

[0060] The composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate in a mass ratio of 4.4:1.6.

[0061] The defoamer is organosilicon defoamer BYK-028.

[0062] The functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate in a mass ratio of 0.8:1.5.

[0063] A method for preparing self-leveling mortar for highway drainage ditches includes the following steps: S1: Mix water with all ingredients except the composite reinforcing agent and functional additives, and prepare the aqueous solution at 400 rpm. Then, mix the aqueous solution with the powdered raw materials prepared from the remaining raw materials and add it to a high-speed mixer; S2: Stir continuously at 750 rpm for 4 minutes in the high-speed mixer. After completion, let the resulting slurry stand for 15 minutes, and then stir again at 600 rpm for 3 minutes. After completion, the self-leveling mortar for highway drainage ditches that can be poured is obtained.

[0064] Example 2

[0065] A self-leveling mortar for highway drainage ditches, comprising the following raw materials by weight: 165 parts gel material, 110 parts graded aggregate, 1.8 parts rheology modifier, 2.3 parts strength modifier, 4.2 parts polymer modifier, 7.5 parts composite reinforcing agent, 0.2 parts defoamer, and 5.2 parts functional additives.

[0066] The gelling material is a combination of silicate cement P·II 52.5, S95 grade blast furnace slag powder and silica fume, with a mass ratio of 11:3.2:0.8.

[0067] The graded aggregate is a combination of 40-70 mesh dry quartz sand and 100-140 mesh dry quartz sand in a mass ratio of 6.5:3.5.

[0068] The rheology modifier is a combination of polycarboxylate superplasticizer and hydroxypropyl methylcellulose ether in a mass ratio of 1.5:0.3.

[0069] The strength modifier is a combination of calcium formate and tartaric acid in a mass ratio of 2.4:0.6.

[0070] The polymer modifier is VAE polymer powder.

[0071] The composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate in a mass ratio of 4.8:1.2.

[0072] The defoamer is organosilicon defoamer BYK-028.

[0073] The functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate in a mass ratio of 1:1.3.

[0074] A method for preparing self-leveling mortar for highway drainage ditches includes the following steps: S1: Mix water with all ingredients except the composite reinforcing agent and functional additives, and prepare the aqueous solution at 400 rpm. Then, mix the aqueous solution with the powdered raw materials prepared from the remaining raw materials and add it to a high-speed mixer; S2: Stir continuously at 750 rpm for 4 minutes in the high-speed mixer. After completion, let the resulting slurry stand for 15 minutes, and then stir again at 600 rpm for 3 minutes. After completion, the self-leveling mortar for highway drainage ditches that can be poured is obtained.

[0075] Example 3

[0076] A self-leveling mortar for highway drainage ditches comprises, by weight, 160 parts of gel material, 110 parts of graded aggregate, 1.8 parts of rheology modifier, 2.3 parts of strength modifier, 4.2 parts of polymer modifier, 9.5 parts of composite reinforcing agent, 0.2 parts of defoamer, and 4.8 parts of functional additives.

[0077] The gelling material is a combination of silicate cement P·II 52.5, S95 grade blast furnace slag powder and silica fume, with a mass ratio of 10:3.5:1.

[0078] The graded aggregate is a combination of 40-70 mesh dry quartz sand and 100-140 mesh dry quartz sand in a mass ratio of 7:3.

[0079] The rheology modifier is a combination of polycarboxylate superplasticizer and hydroxypropyl methylcellulose ether in a mass ratio of 1.6:0.2.

[0080] The strength modifier is a combination of calcium formate and tartaric acid in a mass ratio of 2.7:0.8.

[0081] The polymer modifier is VAE polymer powder.

[0082] The composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate in a mass ratio of 5:2.

[0083] The defoamer is organosilicon defoamer BYK-028.

[0084] The functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate in a mass ratio of 1:1.4.

[0085] A method for preparing self-leveling mortar for highway drainage ditches includes the following steps: S1: Mix water with all ingredients except the composite reinforcing agent and functional additives, and prepare the aqueous solution at 400 rpm. Then, mix the aqueous solution with the powdered raw materials prepared from the remaining raw materials and add it to a high-speed mixer; S2: Stir continuously at 750 rpm for 4 minutes in the high-speed mixer. After completion, let the resulting slurry stand for 15 minutes, and then stir again at 600 rpm for 3 minutes. After completion, the self-leveling mortar for highway drainage ditches that can be poured is obtained.

[0086] Comparative Example 1

[0087] A self-leveling mortar for highway drainage ditches, comprising the following raw materials by weight: 185 parts gel material, 140 parts graded aggregate, 2 parts rheology modifier, 2.8 parts strength modifier, 4.8 parts polymer modifier, 2.1 parts composite reinforcing agent, 0.3 parts defoamer, and 10.5 parts functional additives.

[0088] The remaining implementation methods are the same as in Example 1.

[0089] Comparative Example 2

[0090] A self-leveling mortar for highway drainage ditches, comprising the following raw materials by weight: 185 parts gel material, 140 parts graded aggregate, 2 parts rheology modifier, 2.8 parts strength modifier, 4.8 parts polymer modifier, 11 parts composite reinforcing agent, 0.2 parts defoamer, and 1.5 parts functional additive.

[0091] The remaining implementation methods are the same as in Example 1.

[0092] Comparative Example 3

[0093] A self-leveling mortar for highway drainage ditches, the raw materials, by weight, include: 155 parts of gel material, 110 parts of graded aggregate, 1.8 parts of rheology modifier, 2.3 parts of strength modifier, 4.2 parts of polymer modifier, 8.2 parts of composite reinforcing agent, 0.2 parts of defoamer, and 6.6 parts of functional additives.

[0094] The composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate in a mass ratio of 5.5:0.5.

[0095] The remaining implementation methods are the same as in Example 1.

[0096] Comparative Example 4

[0097] A self-leveling mortar for highway drainage ditches, the raw materials, by weight, include: 155 parts of gel material, 110 parts of graded aggregate, 1.8 parts of rheology modifier, 2.3 parts of strength modifier, 4.2 parts of polymer modifier, 8.2 parts of composite reinforcing agent, 0.2 parts of defoamer, and 6.6 parts of functional additives.

[0098] The composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate in a mass ratio of 1.5:4.5.

[0099] The remaining implementation methods are the same as in Example 1.

[0100] Comparative Example 5

[0101] A self-leveling mortar for highway drainage ditches, the raw materials, by weight, include: 155 parts of gel material, 110 parts of graded aggregate, 1.8 parts of rheology modifier, 2.3 parts of strength modifier, 4.2 parts of polymer modifier, 8.2 parts of composite reinforcing agent, 0.2 parts of defoamer, and 6.6 parts of functional additives.

[0102] The functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate in a mass ratio of 0.2:2.1.

[0103] The remaining implementation methods are the same as in Example 1.

[0104] Comparative Example 6

[0105] A self-leveling mortar for highway drainage ditches, the raw materials, by weight, include: 155 parts of gel material, 110 parts of graded aggregate, 1.8 parts of rheology modifier, 2.3 parts of strength modifier, 4.2 parts of polymer modifier, 8.2 parts of composite reinforcing agent, 0.2 parts of defoamer, and 6.6 parts of functional additives.

[0106] The functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate in a mass ratio of 1.8:0.5.

[0107] The remaining implementation methods are the same as in Example 1.

[0108] Performance evaluation test

[0109] 1. Compressive strength: The prepared mortar slurry was injected into a triple mold of 40mm×40mm×160mm, and filled by its own weight. The excess was scraped off. The mold was placed in a curing chamber at 20±1℃ and relative humidity ≥90% for curing. The compressive strength was tested using six broken half specimens with a bearing area of ​​40mm×40mm and a loading rate of 2400N / s. The failure load was recorded. The results were the average of 10 tests of compressive strength after 3 days and 28 days of curing, and recorded in Table 1.

[0110] 2. Anti-sagging: The prepared mortar is loaded into a standard wet film preparation device, and a continuous coating with an initial thickness of 10 mm and a width of 10 cm is uniformly scraped onto the bottom of a smooth steel plate at a 60° angle. After standing for 10 minutes, the thickness values ​​at the top, middle and bottom of the coating are measured to obtain the average remaining thickness at the three points. The retention rate (%) is calculated as (average remaining thickness / initial thickness) × 100%. The average retention rate at the three points is recorded in Table 1.

[0111] 3. Bond strength: Using C30 old concrete slab as the substrate, after roughening and cleaning the surface, a Φ50mm×20mm metal ring mold was installed on the substrate. The prepared mortar was poured into the mold, leveled, and cured in a curing chamber at 20±1℃ and relative humidity ≥90% for 28 days. Then, the tensile joint was bonded to the surface of the mortar block with epoxy adhesive (Z-971, Guangdong Zhong'an New Materials) for 24 hours. Tensile testing was then performed at a rate of 2500N / s using a tensile testing machine, and the failure load was recorded. The average of 10 tests was recorded in Table 1.

[0112] Table 1 Performance Test Results 1

[0113]

[0114] Test Result Analysis: The test results above demonstrate that the embodiments exhibit superior compressive strength, bond strength, and anti-sagging performance compared to the comparative examples. In particular, comparative examples 1 and 2, due to the significant increase in the total amount of cementitious materials and aggregates, as well as the excessive amount of composite reinforcing agents and insufficient functional additives, reduced the fluidity of the paste and hindered the normal hydration of cement particles, resulting in slow strength development and weakened workability retention, thus achieving poorer overall performance.

[0115] In contrast, in comparisons 3 to 6, the changes in composite reinforcing agents and functional additives directly affected the technical effects of the corresponding raw materials within the mortar, significantly weakening their combined effect and ultimately resulting in worse performance results in the corresponding comprehensive performance tests.

[0116] 4. Impermeability: The mortar was molded to a size of 175mm at the top, 185mm at the bottom, and 150mm in height, and cured in a curing chamber at 20±1℃ and relative humidity ≥90% for 28 days. After sealing the sides of the specimens, they were installed on a concrete impermeability tester. The test was started with a water pressure of 0.2MPa and kept at a constant pressure for 8 hours. Then, the water pressure was increased by 0.1MPa every 8 hours until water seepage was observed on the surface of 3 out of 6 specimens in a group. The water pressure value at this point was recorded, and the average of 10 tests was recorded in Table 2.

[0117] 5. Freeze-thaw resistance: Mortar was molded into prism specimens of 100mm×100mm×400mm, cured in a curing chamber at 20±1℃ and relative humidity ≥90% for 28 days, and then soaked in water for 4 days. After that, the specimens were subjected to freeze-thaw cycles, each cycle was completed within 4 hours, and the core temperature was controlled at -18±2℃ (2h) and 5±2℃ (2h) respectively. After 300 cycles, the mass loss rate was recorded in Table 2.

[0118] 6. Drying Shrinkage: Mortar was molded into prism specimens measuring 100mm × 100mm × 515mm, with probes embedded at both ends. The probe lengths were recorded. After curing in a curing chamber at 20±1℃ and relative humidity ≥90% for 3 days, the specimens were demolded, and the initial length L0 was measured. The specimens were then moved to a constant temperature and humidity chamber at 20±1℃ and relative humidity 65±2%, and their length Lt after 90 days was measured. The drying shrinkage value was calculated as: (L0 - Lt) / gauge length (515 - 2 × probe length) × 10 6 (µm / m), the results are recorded in Table 2.

[0119] Table 2 Performance Test Results 2

[0120]

[0121] Test results analysis: Comparative Examples 1-6 all disrupted the performance balance of the composite additive system, resulting in shortcomings in any dimension of the mortar microstructure, such as density, hydrophobic uniformity, or stability of hydration products. This led to deterioration in long-term performance in terms of impermeability, freeze-thaw resistance, or shrinkage resistance. This further demonstrates the unexpectedly superior effect of the combined functional components in the embodiments of this invention.

Claims

1. A self-leveling mortar for highway drainage ditches, characterized in that: The raw materials include at least gelling materials and graded aggregates, with a mass ratio of gelling materials to graded aggregates of (14~17):(9~12), as well as composite reinforcing agents and functional additives; The gel material is a combination of cement, slag powder and silica fume, in a mass ratio of (9~11):(2~3.5):(0.5~1.2). The graded aggregate is a combination of 40-70 mesh dry quartz sand and 100-140 mesh dry quartz sand, with a mass ratio of (6-7):(3-4). The composite reinforcing agent is a combination of glyceryl monostearate and sodium molybdate in a mass ratio of (4~5):(1~2). The functional additive is a combination of tetrahydroxypropylethylenediamine and calcium nitrate, with a mass ratio of (0.5~1):(1.3~1.6). The mass ratio of the gel material, composite reinforcing agent, and functional additive is (14~17):(0.6~1):(0.4~1).

2. The self-leveling mortar for highway drainage ditches according to claim 1, characterized in that: The mass ratio of the gel material, composite reinforcing agent, and functional additive is (15~16.5):(0.8~0.9):(0.6~0.7).

3. The self-leveling mortar for highway drainage ditches according to claim 2, characterized in that: The cement is silicate cement or ordinary silicate cement.

4. The self-leveling mortar for highway drainage ditches according to claim 3, characterized in that: The strength grade of the cement is 52.5 or 52.5R.

5. The self-leveling mortar for highway drainage ditches according to claim 4, characterized in that: The slag powder is blast furnace slag powder; the blast furnace slag powder is at least one of S75 grade, S95 grade and S105 grade.

6. The self-leveling mortar for highway drainage ditches according to claim 5, characterized in that: The self-leveling mortar for highway drainage ditches also includes rheology modifiers, strength modifiers, polymer modifiers, and defoamers in its raw materials.

7. The self-leveling mortar for highway drainage ditches according to claim 6, characterized in that: The rheology modifier is a combination of polycarboxylate superplasticizer and hydroxypropyl methylcellulose ether, with a mass ratio of (1~2):(0.2~0.4).

8. The self-leveling mortar for highway drainage ditches according to claim 7, characterized in that: The strength modifier is a combination of calcium formate and tartaric acid in a mass ratio of (2~3):(0.5~1).

9. The self-leveling mortar for highway drainage ditches according to claim 8, characterized in that: The polymer modifier is VAE polymer powder.

10. A method for preparing self-leveling mortar for highway drainage ditches according to any one of claims 1 to 9, characterized in that: Includes the following steps: S1: Mix all ingredients except the composite reinforcing agent and functional additives with water at 300-400 rpm to prepare an aqueous solution. Then, mix the aqueous solution with the powdered raw materials prepared from the remaining ingredients and add it to a high-speed mixer. S2: Stir continuously at 600-800 rpm for 4-5 minutes in a high-speed mixer. After completion, let the resulting slurry stand for 10-15 minutes, and then stir again at 500-700 rpm for 2-3 minutes. After completion, you will get a castable self-leveling mortar for highway drainage ditches.

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