Compaction-free early-strength emulsified asphaltic sand for repairing waterproof layer of high-speed rail bridge floor and preparation method thereof

Abstract

The invention discloses compaction-free early-strength emulsified asphaltic sand for repairing a waterproof layer of a high-speed rail bridge floor and a construction method of the compaction-free early-strength emulsified asphaltic sand. The compaction-free early-strength emulsified asphalt sand comprises the following components in percentage by weight: 55-75% of machine-made sand with the particle size of 0.075-4.75 mm; 10%-20% of river sand with the particle size of 0.075 mm to 4.75 mm; 5%-10% of mineral powder with the particle size of 0-0.075 mm; 1%-2% of semi-hydrated gypsum with the particle size of 0-0.075 mm; 0%-1% of lignin fiber; 12%-16% of high water retention emulsified asphalt; and 2%-4% of water. By designing the composition of the emulsified asphalt and the proportion of the emulsified asphalt sand, the waterproof performance and the crack resistance of the emulsified asphalt sand under the compaction-free condition are realized, and the problem that the emulsified asphalt sand for the operation high-speed rail bridge deck waterproof layer is difficult to construct by adopting a road roller is solved.

Description

Technical Field

[0001] This invention relates to an asphalt sand and its construction method, and more particularly to a non-compacting, early-strength emulsified asphalt sand and its preparation method. Background Technology

[0002] Currently, my country's total operational high-speed rail mileage exceeds 46,000 kilometers. The waterproofing layer on high-speed rail bridge decks typically uses 6cm thick cast-in-place fiber-reinforced concrete, with silicone sealant used for longitudinal and transverse joints. However, with prolonged service life, under the long-term effects of freeze-thaw cycles, extreme weather, and high-frequency train loads, the waterproofing layer gradually develops defects such as concrete cracking, powdering, aggregate spalling, and silicone sealant failure. This leads to rainwater infiltration, causing a decrease in the load-bearing capacity and durability of the underlying bridge structure, thus affecting the operational safety and service life of the high-speed rail.

[0003] Existing materials for repairing waterproofing layers on high-speed railway bridge decks mainly include coatings and mortars. Coatings include polyurethane coatings and emulsified asphalt coatings, typically less than 5mm thick. While these materials are economical and effective in the short term, they are prone to peeling and detachment under long-term aging and high-speed train vibration loads, posing significant safety hazards. Mortars mainly include cement mortar and polymer-modified cement mortar, typically 3-5cm thick. Cement mortar, being thicker, adheres better to the substrate and has a lower risk of detachment, but it is prone to secondary cracking and powdering. Furthermore, the caulking material at transverse and longitudinal expansion joints is prone to separation, leading to waterproofing failure. Polymer-modified mortar exhibits good frost resistance, crack resistance, and durability, but its higher cost limits its practical application. Therefore, developing new materials suitable for repairing waterproofing layers on high-speed railway bridge decks is of great significance.

[0004] The standard QCR 1041, "Asphalt Concrete for Railway Subgrade," identifies asphalt mixtures as an excellent waterproofing material for high-speed railways. Researchers compared the application effects of cement concrete and asphalt mixtures in the waterproofing layer of the Beijing-Zhangjiakou high-speed railway. The results showed that under the same environmental conditions and train loads, cement concrete waterproofing layers exhibited more cracks, powdering, and joint separation at contact points, while asphalt mixtures showed fewer defects. This is because asphalt mixtures are flexible materials with good deformation capacity and frost resistance, reducing the risk of low-temperature cracking. However, the following limitations exist in the maintenance and repair of asphalt mixtures suitable for waterproofing layers on newly constructed high-speed railway bridge decks: ① Due to the constraints of surrounding structures, road rollers cannot be used for the maintenance and repair of bridge deck waterproofing layers; ② Due to limitations in transportation conditions and construction time, asphalt mixture materials are difficult to heat.

[0005] Existing technology 1: ZL201410301073.4 discloses a cold-mixed and cold-laid modified emulsified asphalt mixture and its construction equipment and method. This emulsified asphalt mixture comprises 75%–90% graded crushed stone with a particle size of 0.075–13.2 mm, 9%–15% SBS modified emulsified asphalt, 0%–5% ordinary Portland cement, 0%–7% water, and 0%–0.1% quaternary ammonium salt additives. After paving, this emulsified asphalt mixture requires compaction at least six times using a 6-8T steel wheel roller or a 25T rubber-tired roller. The cold-mixed modified emulsified asphalt mixture used in this technology is mainly suitable for road maintenance. However, there are some differences between the maintenance of waterproof layers for high-speed railway bridge decks and road surface maintenance: ① Road surfaces have no surrounding restraint structures, while the waterproof layers of high-speed railway bridge decks are constrained by ballastless track structures, crash barriers, and contact wire support bases, making it impossible to use large compaction equipment for rolling. The compaction and waterproofing of road asphalt mixtures are mainly achieved through rolling; ② There are vertical joints between the waterproof layers of high-speed railway bridge decks and the surrounding structures. These joints are usually weak points in waterproofing, and using coarse-grained gradation can easily lead to water seepage at these joints. Therefore, the repair materials in Comparative Document 1 are not suitable for the maintenance of waterproof layers on high-speed railway bridge decks.

[0006] Prior art 2: ZL201910599651.X discloses a durable flexible structure and construction method for treating the waterproof sealing layer of high-speed railway subgrade. The waterproof layer uses emulsified asphalt sand, comprising, by weight percentage, 88%~93% manufactured sand with a particle size of 0.075~4.75mm and 7%~12% SBR modified emulsified asphalt. The construction method involves evenly spreading the pre-mixed emulsified asphalt sand on the construction surface, leveling it with a rake, and compacting it with a plate rammer. This technology uses a plate rammer to lightly compact the emulsified asphalt sand to form a waterproof layer for repairing the waterproof layer of high-speed railway subgrade; however, the plate rammer is difficult to compact at the joints between the emulsified asphalt sand and the surrounding track structure, crash barriers, and contact wire support bases, making these joints prone to becoming weak waterproof areas; in addition, the subgrade waterproof layer has a large planar area, allowing for a wide operating range for the plate rammer, while the bridge deck waterproof layer has a smaller operating space, especially between the track structure and crash barriers. Therefore, the repair material in prior art 2 has certain limitations in the maintenance and repair of the waterproof layer of high-speed railway bridge decks.

[0007] Prior art 3: ZL201710346138.0 discloses a method and structure for concrete repair and protection based on asphalt materials. The thermal insulation and protective layer is a precast asphalt mixture slab 2-6cm thick and 5-10m long, and the joints are filled with asphalt binder at 140℃. The precast asphalt mixture slab is composed of modified asphalt at 180℃, polymer fibers, and aggregates of 0.075-4.75mm. The construction efficiency of precast asphalt mixture slabs is relatively high, but large equipment is required for transportation and installation, and the construction process requirements are high. In addition, because the size of the precast slabs is relatively uniform, it is mainly suitable for standard-sized areas, and it is difficult to apply to non-standard areas such as turnout areas, contact wire support base areas, and narrow areas between track structures and crash barriers. Therefore, the repair material in prior art 3 has certain limitations in the maintenance and repair of waterproof layers on high-speed railway bridge decks. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention discloses a non-compacting, early-strength emulsified asphalt sand, the technical solution of which is as follows:

[0009] A non-compacting, early-strength emulsified asphalt sand, by weight percentage, comprises:

[0010] Manufactured sand with a particle size of 0.075~4.75mm, 55%~75%;

[0011] River sand with a particle size of 0.075~4.75mm, 10%~20%;

[0012] Mineral powder with a particle size of 0~0.075mm, 5%~10%;

[0013] Hemihydrate gypsum with a particle size of 0~0.075mm, 1%~2%;

[0014] Lignin fiber, 0%~1%;

[0015] High water-retention emulsified asphalt, 12%~16%;

[0016] Water, 2%~4%.

[0017] As a further improvement of the present invention, the high water-retaining emulsified asphalt is made of SBS modifier with low block ratio, petroleum asphalt with high aromatic hydrocarbon content, emulsifier with high non-polar group content, water-retaining agent, thickener and water, and has high water-retaining and strong bonding properties. The non-compacting early-strength emulsified asphalt sand formulated with high water-retaining emulsified asphalt has good fluidity.

[0018] The second objective of this invention is to provide an application of non-compacted early-strength emulsified asphalt sand. Based on the characteristics of the non-compacted early-strength emulsified asphalt sand having good fluidity, high early strength, dense waterproofing, and excellent crack resistance, the non-compacted early-strength emulsified asphalt sand can be used in working conditions where it is difficult to use compaction equipment, such as the repair of waterproofing layers on operating high-speed railway bridge decks.

[0019] Beneficial effects

[0020] (1) Compared with existing technologies where emulsified asphalt sand requires compaction equipment such as road rollers and plate compactors, this invention uses high water-retaining emulsified asphalt, free-flowing river sand, and optimized material ratios to prepare compaction-free early-strength emulsified asphalt sand, which is suitable for the working conditions where compaction equipment is difficult to use in the repair of waterproof layers on high-speed railway bridge decks. The use of hemihydrate gypsum, lignin fiber, and other additives ensures the early strength and crack resistance of the compaction-free early-strength emulsified asphalt sand waterproof layer.

[0021] (2) The joint between the waterproof layer and the surrounding track structure, crash barrier, and contact wire support base is usually a weak waterproof part. The non-compacted early-strength emulsified asphalt sand of the present invention has a certain fluidity, which can fill the gap between the waterproof layer and the surrounding structure and achieve good bonding, reducing the risk of gaps and water leakage between the bridge deck waterproof layer and the surrounding structure.

[0022] (3) Compared with existing coating materials for repairing waterproof layers of high-speed railway bridge decks, the non-compacting early-strength emulsified asphalt sand of the present invention has a low risk of falling off, strong anti-aging properties, and long service life.

[0023] (4) Compared with existing cement mortar materials used for repairing waterproof layers on high-speed railway bridge decks, the emulsified asphalt sand of the present invention does not require expansion joints or caulking, thus avoiding the risk of water leakage at expansion joints; and the deformability, frost resistance, crack resistance, and impermeability of the non-compacted early-strength emulsified asphalt sand of the present invention are significantly improved compared with cement mortar. Compared with existing polymer cement mortar materials, the cost of the non-compacted early-strength emulsified asphalt sand of the present invention is only 1 / 3, which is more economical. Attached Figure Description

[0024] Figure 1 The impact of compaction on the state of emulsified asphalt sand in existing technologies;

[0025] Figure 2 The influence of petroleum asphalt on the microstructure of modified asphalt;

[0026] Figure 3 To avoid compaction, early-strength emulsified asphalt sand is used in the field. Detailed Implementation

[0027] The first objective of this invention is to provide a non-compacting, early-strength emulsified asphalt sand, comprising, by weight percentage:

[0028] Manufactured sand with a particle size of 0.075~4.75mm, 55%~75%;

[0029] River sand with a particle size of 0.075~4.75mm, 10%~20%;

[0030] Mineral powder with a particle size of 0~0.075mm, 5%~10%;

[0031] Hemihydrate gypsum with a particle size of 0~0.075mm, 1%~2%;

[0032] Lignin fiber, 0%~1%;

[0033] High water-retention emulsified asphalt, 12%~16%;

[0034] Water, 2%~4%.

[0035] Comparative Example 1:

[0036] To determine the effect of compaction on the compaction performance of emulsified asphalt sand in existing technologies, the mix proportion of cold-mixed and cold-laid emulsified asphalt sand in existing technology 1 (background art) was referenced. 85% manufactured sand (0.075~4.75mm), 12% emulsified asphalt, 2% water, and 1% ordinary Portland cement were uniformly mixed. One set of tests was conducted according to JTG E20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". The emulsified asphalt sand was filled into molds and compacted on both sides using a compactor. Figure 1 As shown in (a); another group of tests directly filled the emulsified asphalt mixture into the mold, as shown in (a). Figure 1 As shown in (b). Figure 1 (a) The surface of the medium-compacted specimen is flat, dense, and waterproof, while Figure 1 (b) The uncompacted specimens showed loose particles and severe water leakage. It is evident that compaction significantly affects the compaction and waterproofing performance of emulsified asphalt sand, and existing emulsified asphalt sand technologies are difficult to apply to uncompacted conditions.

[0037] Example 1:

[0038] To prepare dense, waterproof, non-compacted, early-strength emulsified asphalt sand, the parameters of the emulsified asphalt were optimized, as shown in Table 1. 2-1 represents the baseline mix proportion in Comparative Example 1. 2-1 to 2-3 all use emulsified asphalt from existing technologies, while 2-4 to 2-6 all use the high-water-retention emulsified asphalt of this invention. It can be seen that when using emulsified asphalt from existing technologies, at a content of 16% (2-2), the mixture remains granular and lacks fluidity; only at a content of 20% (2-3) does the mixture begin to exhibit a viscous state with a fluidity of 120 mm, reaching the minimum value for non-compacted construction. When using high-water-retention emulsified asphalt, at a dosage of 20% (2-4), the mixture is in a slurry state with some segregation, and the fluidity reaches 250 mm; at a dosage of 16% (2-5), the mixture is in a uniform, thick slurry state with a fluidity of 170 mm, showing good condition; at a dosage of 12%, the mixture is in a viscous state with a fluidity of 120 mm, reaching the minimum value for pressure-free construction. This indicates that using high-water-retention emulsified asphalt can improve the fluidity of emulsified asphalt sand, achieving pressure-free construction under lower dosage conditions.

[0039] Table 1. Effect of high water-retaining emulsified asphalt on the flowability of uncompacted, early-strength emulsified asphalt sand.

[0040] Proportion Emulsified asphalt High water retention emulsified asphalt Manufactured sand water Ordinary Portland cement Flowability (mm) 2-1 12% / 85% 2% 1% / 2-2 16% / 81% 2% 1% / 2-3 20% / 77% 2% 1% 120 2-4 / 20% 77% 2% 1% 250 2-5 / 16% 81% 2% 1% 170 2-6 / 12% 85% 2% 1% 120

[0041] To prepare high water-retention emulsified asphalt, the commonly used low-block ratio SBS modifier was employed. Two types of petroleum asphalt, A1 and A2, were selected for modification. The results are as follows: Figure 2 As shown in Table 2, A2 modified asphalt exhibits large particle aggregation and some segregation, while A1 is uniformly dispersed, has smaller particle size, and better compatibility. This is because A1 asphalt has the highest aromatic hydrocarbon content, which, according to the principle of similar compatibility, allows the hard segments in SBS to be released and dissolved into the asphalt, thus resulting in better stability of the modified asphalt.

[0042] Table 2. Effect of petroleum asphalt on the homogeneity of modified asphalt

[0043] Petroleum asphalt type Aromatic hydrocarbons gelatinous Saturated hydrocarbons Asphalt Top and bottom segregation values ​​of modified asphalt A1 47.5% 29.0% 14.3% 9.2% 2.2 A2 32.1% 39.1% 22.7% 6.1% 12.7

[0044] Furthermore, emulsifier B1 (HLB value 9) with high non-polar group content, emulsifier B2 (HLB value 6) with high polar group content, superabsorbent resin water-retaining agent C1 (water absorption ratio of 120 times), and nonionic polyurethane thickener D1 (viscosity of 5000 mPa·S) were selected, and emulsified asphalt was prepared by using a colloid mill, and then mixed into emulsified asphalt sand. Table 3 shows that without a water-retaining agent, the uncompacted emulsified asphalt sand mixture is in a loose state and cannot be used as a waterproof layer. With only a water-retaining agent, the fluidity of the emulsified asphalt sand can be improved, and the uncompacted emulsified asphalt sand is in a slurry state. Although it can achieve uncompacted construction, there is a small amount of segregation and bleeding, and the material uniformity is insufficient. When both a water-retaining agent and a thickener are used, the fluidity of the emulsified asphalt sand can be improved uniformly, and there is no segregation or bleeding. Therefore, using emulsifier B1, water-retaining agent C1, and thickener D1 can prepare high water-retaining emulsified asphalt. The emulsified asphalt sand mixed and formed has a greater fluidity than existing emulsified asphalt sand and no segregation or bleeding.

[0045] Table 3. Effect of emulsified asphalt mix proportion on the mixing state of uncompacted emulsified asphalt sand

[0046] Serial Number emulsifier Water-retaining agent Thickener Emulsified asphalt sand mixing state 1 B2 / / granules 2 B1 C1 / Thin slurry, with a small amount of segregated water. 3 B1 C1 D1 Thick slurry, no segregation

[0047] Example 2:

[0048] Furthermore, based on the 2-6 mix proportion, an optimized design for the early-strength emulsified asphalt sand mix proportion without compaction was carried out using river sand, as shown in Table 4. All mix proportions used the high water-retention emulsified asphalt proposed in this patent. It can be seen that after adding river sand (3-1 to 3-3), the fluidity of the emulsified asphalt sand mixture gradually increased, but the water permeability coefficient also gradually increased, meaning the waterproofing performance deteriorated, and the splitting strength gradually decreased. This is because river sand has no sharp edges and a smoother surface than manufactured sand, resulting in better fluidity of the mixture; however, because river sand is approximately spherical, the particles are difficult to pack tightly, resulting in a high porosity and poor waterproofing performance of the emulsified asphalt sand. At the same time, the smooth surface of river sand and the weak interlocking force between particles lead to a reduction in the strength of the emulsified asphalt sand. Specifically, when the river sand content reaches 30%, the fluidity of the emulsified asphalt sand reaches 240 mm, and there is a certain degree of segregation and bleeding; the permeability coefficient is 90 mL / min, which exceeds the waterproof requirement of less than 80 mL / min; the splitting strength is 0.24 MPa, which is lower than the stress requirement of more than 0.3 MPa. Therefore, in order to improve the flow state of the non-compacted early-strength emulsified asphalt sand, the river sand content should be 10%~20%.

[0049] Table 4. Effect of River Sand on the Properties of Uncompacted Emulsified Asphalt Sand

[0050] Proportion High water retention emulsified asphalt Manufactured sand river sand Ordinary Portland cement water Flowability (mm) Permeability coefficient (mL / min) Splitting strength MPa 2-6 12% 85% 0% 1% 2% 120 0 0.38 3-1 12% 75% 10% 1% 2% 160 30 0.35 3-2 12% 65% 20% 1% 2% 200 60 0.31 3-3 12% 55% 30% 1% 2% 240 90 0.24 3-4 10% 55% 30% 1% 2% 180 110 0.20

[0051] Furthermore, uncompacted emulsified asphalt sand was mixed using commonly used sand (manufactured sand or river sand) with a particle size of 0-4.75mm and dust-removed sand (0.075-4.75mm) according to this technology. The results showed that when using sand of the commonly used particle size, the emulsified asphalt sand easily agglomerated, failing to achieve a dense and waterproof state. However, when using dust-removed sand, the emulsified asphalt sand exhibited good fluidity. This is because the 0-0.075mm particle size portion of manufactured sand or river sand mainly consists of highly absorbent clay. When emulsified asphalt comes into contact with clay, it easily breaks down and agglomerates, reducing the fluidity of the emulsified asphalt sand mixture. Therefore, uncompacted emulsified asphalt sand should use dust-removed sand with a particle size of 0.075-4.75mm. Simultaneously, mineral powder with a particle size of 0-0.075mm is used to replace the 0-0.075mm clay to fill the voids between the 0.075-4.75mm sand particles, thus giving the uncompacted emulsified asphalt sand better density and waterproof properties.

[0052] Example 3:

[0053] Furthermore, based on the 3-2 mix design, fiber-based optimization of the early-strength emulsified asphalt sand mix design without compaction was carried out, as shown in Tables 5 and 6. All mix designs used the high-water-retention emulsified asphalt proposed in this patent. It can be seen that after adding different types of fibers (4-1 to 4-3), the fluidity of the emulsified asphalt sand mixture decreased, while the splitting strength and low-temperature flexural strain increased, indicating improved strength and crack resistance. This is because the addition of fibers reduces the viscosity and fluidity of the emulsified asphalt sand mixture due to fiber resistance, and the fiber overlap enhances the toughness, tensile strength, and crack resistance. However, the addition of polypropylene and basalt fibers reduced the water resistance of the emulsified asphalt sand, with the permeability coefficient exceeding the critical water resistance value of 80 ml / min. This is because polypropylene and basalt fibers are long and strip-shaped, and the overlap within the emulsified asphalt sand creates channels for water to enter and exit, thus reducing water resistance. However, the addition of lignin fiber improves the waterproofness of emulsified asphalt sand. This is because lignin fiber is in clumps and dispersed inside the emulsified asphalt sand, and cannot overlap to form channels for water to enter and exit. In addition, lignin fiber has a certain water absorption capacity, which can reduce the voids formed by water evaporation in the emulsified asphalt sand, thus improving the compactness of the emulsified asphalt sand. Therefore, in order to improve the crack resistance of non-compacted early-strength emulsified asphalt sand, lignin fiber should be used instead of polypropylene fiber and basalt fiber.

[0054] Table 5 Different fiber ratios for uncompacted emulsified asphalt sand

[0055] Proportion High water retention emulsified asphalt Manufactured sand river sand fiber Ordinary Portland cement water 3-2 12% 65% 20% / 1% 2% 4-1 (Polypropylene fiber) 12% 64% 20% 1% 1% 2% 4-2 (Basalt Fiber) 12% 64% 20% 1% 1% 2% 4-3 (Lignin Fiber) 12% 64% 20% 1% 1% 2%

[0056] Table 6. Influence of Fibers on the Properties of Uncompacted Emulsified Asphalt Sand

[0057] Proportion Flowability (mm) Splitting strength MPa Low temperature bending strain με Permeability coefficient (mL / min) 3-2 200 0.31 2800 60 4-1 (Polypropylene fiber) 180 0.44 4200 90 4-2 (Basalt Fiber) 170 0.42 4100 90 4-3 (Lignin Fiber) 160 0.38 3500 50

[0058] Example 4:

[0059] Furthermore, based on the 4-3 mix design, gypsum was used to replace the existing ordinary Portland cement for optimized design of non-compacted, early-strength emulsified asphalt sand mix design, as shown in Tables 7 and 8. It can be seen that after replacing ordinary Portland cement with different types of gypsum (5-1 to 5-3), the 1-day compressive strength of the emulsified asphalt sand increased, with hemihydrate gypsum > dihydrate gypsum > anhydrous gypsum. This is because gypsum cures faster than ordinary Portland cement, and hemihydrate gypsum cures even faster than dihydrate and anhydrous gypsum. With the increase of hemihydrate gypsum content (5-3 to 5-5), the increase in 1-day compressive strength of the emulsified asphalt sand was relatively small. This is because the gypsum content is small, and its main role in the emulsified asphalt sand is to absorb water and promote setting, while the strength mainly relies on the bonding force formed after the emulsified asphalt breaks down. Meanwhile, with the addition of gypsum, the brittleness of emulsified asphalt sand increases and the low-temperature flexural strain gradually decreases. In particular, when the amount of hemihydrate gypsum added is 3%, the low-temperature flexural strain reaches 2800με, and the crack resistance of emulsified asphalt sand is difficult to guarantee. Therefore, in order to balance the early strength and later crack resistance of non-compacted early-strength emulsified asphalt sand, the amount of hemihydrate gypsum should be 1%~2%.

[0060] Table 7 Different gypsum mix proportions for uncompacted emulsified asphalt sand

[0061] Proportion High water retention emulsified asphalt Manufactured sand river sand Lignin fibers Ordinary Portland cement plaster water 4-3 12% 64% 20% 1% 1% / 2% 5-1 (Anhydrous Plaster) 12% 64% 20% 1% / 1% 2% 5-2 (Dihydrate Gypsum) 12% 64% 20% 1% / 1% 2% 5-3 (Hemihydrate gypsum) 12% 64% 20% 1% / 1% 2% 5-4 (Hemihydrate gypsum) 12% 64% 20% 1% / 2% 2% 5-5 (Hemihydrate gypsum) 12% 64% 20% 1% / 3% 2%

[0062] Table 8. Effect of gypsum on the properties of uncompacted emulsified asphalt sand

[0063] Proportion Flowability (mm) 1d compressive strength (MPa) Splitting strength MPa Low temperature bending strain με Permeability coefficient (mL / min) 4-3 160 0.1 0.38 3500 50 5-1 (Anhydrous Plaster) 160 0.4 0.39 3200 50 5-2 (Dihydrate Gypsum) 160 0.5 0.39 3200 50 5-3 (Hemihydrate gypsum) 160 0.8 0.39 3200 50 5-4 (Hemihydrate gypsum) 160 0.9 0.40 3000 50 5-5 (Hemihydrate gypsum) 160 1.0 0.41 2800 50

[0064] Example 5:

[0065] Furthermore, the design of uncompacted early-strength emulsified asphalt sand with different mix proportions of 12%~16% high water-retaining emulsified asphalt and 2%~4% water was optimized, as shown in Tables 9 and 10. It can be seen that when the content of high water-retaining emulsified asphalt is 12%~16% and the water content is 2%~4%, the uncompacted emulsified asphalt sand exhibits good fluidity (120~210mm), early strength (>0.5MPa), crack resistance (>2800με), and water resistance (< 80mL / min), meeting the functional requirements of the waterproof layer.

[0066] Table 9. Mixing ratios of different high water-retaining emulsified asphalt and water for uncompacted emulsified asphalt sand

[0067] Proportion High water retention emulsified asphalt Manufactured sand river sand Lignin fibers Mineral powder hemihydrate gypsum water 6-1 12% 57% 20% 1% 7% 1% 2% 6-2 14% 55% 20% 1% 7% 1% 2% 6-3 16% 53% 20% 1% 7% 1% 2% 6-4 12% 56% 20% 1% 7% 1% 3% 6-5 12% 55% 20% 1% 7% 1% 4%

[0068] Table 10. Effects of water-retaining emulsified asphalt and water content on the properties of uncompacted emulsified asphalt sand.

[0069] Proportion Flowability (mm) 1d compressive strength (MPa) Splitting strength MPa Low temperature bending strain με Permeability coefficient (mL / min) 6-1 160 0.8 0.39 3200 50 6-2 180 0.9 0.41 3400 40 6-3 200 1 0.42 3500 30 6-4 180 0.7 0.38 3100 55 6-5 200 0.6 0.36 2900 60

[0070] Example 6:

[0071] Furthermore, this technology was demonstrated and verified on-site in the waterproofing layer of high-speed railway bridge decks, such as... Figure 3 As shown in the figure. Using the proportions of this invention, 56% manufactured sand, 7% mineral powder, 20% river sand, 13% high water-retaining emulsified asphalt, 1% hemihydrate gypsum, 1% lignin fiber, and 2% mixing water are uniformly mixed to form emulsified asphalt sand. The pre-mixed and sealed barrelled non-compacted early-strength emulsified asphalt sand is transported to the site and evenly spread to a thickness of 40mm. After natural curing, a field survey is conducted on the above-mentioned non-compacted early-strength emulsified asphalt sand waterproof layer. No cracks or water leakage are found within a 100m length.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A high water-retention emulsified asphalt, characterized in that: The high water-retaining emulsified asphalt is made from SBS modifier with low block ratio, petroleum asphalt with high aromatic hydrocarbon content, emulsifier with high non-polar group content, water-retaining agent, thickener, and water.

2. The high water-retention emulsified asphalt according to claim 1, characterized in that: The mass percentages of SBS modifier with low block ratio, petroleum asphalt with high aromatic hydrocarbon content, emulsifier with high non-polar group content, water-retaining agent, thickener, and water are: 2~4%, 55~60%, 2~4%, 1~2%, 1~2%, and 30~40%.

3. The high water-retention emulsified asphalt according to claim 1, characterized in that: The petroleum asphalt with high aromatic hydrocarbon content is selected from Sinopec's Grade A road petroleum asphalt.

4. The high water-retention emulsified asphalt according to claim 1, characterized in that: Petroleum asphalt with high aromatic hydrocarbon content uses the following mass percentages: aromatic hydrocarbons 45-60%, saturated hydrocarbons 10-20%, resins 25-35%, and asphaltenes 5-15%.

5. The high water-retention emulsified asphalt according to claim 1, characterized in that: The emulsifier B1, which has a high content of non-polar groups, has an HLB value of 8 to 12; the superabsorbent resin-based water-retaining agent C1 has a water absorption ratio of more than 100 times; and the nonionic polyurethane thickener D1 has a viscosity of less than 5500 mPa·s.

6. A non-compacting, early-strength emulsified asphalt sand, characterized in that, By weight percentage, including: Manufactured sand with a particle size of 0.075~4.75mm, 55%~75%; River sand with a particle size of 0.075~4.75mm, 10%~20%; Mineral powder with a particle size of 0~0.075mm, 5%~10%; Hemihydrate gypsum with a particle size of 0~0.075mm, 1%~2%; Lignin fiber, 0%~1%; The high water-retention emulsified asphalt described in claim 1 is used, with a content of 12% to 16%. Water, 2%~4%.

7. Waterproof layer for high-speed railway bridge deck, characterized by: The waterproof layer uses the non-compacting, early-strength emulsified asphalt sand as described in claim 6.

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