阅读说明：本技术 一种低收缩水泥稳定土 (Low-shrinkage cement stabilized soil ) 是由 李君超 于 2021-07-20 设计创作，主要内容包括：本申请公开了一种低收缩水泥稳定土,属于路基材料技术领域,其技术方案要点是,所述水泥稳定土原料主要由土、水泥、土凝岩、硅藻土、外加剂以100：(3-6)：(11-15)：(9-21)：(3-7)的质量比复配而成,达到降低水泥稳定土层的干缩性能的效果。(The application discloses low shrink cement stabilized soil belongs to road bed material technical field, and its technical scheme main points are, cement stabilized soil raw materials mainly by soil, cement, soil concretion, diatomaceous earth, additive with 100: (3-6): (11-15): (9-21): and (3-7) to achieve the effect of reducing the drying shrinkage performance of the cement stabilized soil layer.)

1. A low-shrinkage cement stabilized soil is characterized in that: the cement stabilized soil is prepared from the following raw materials of soil, cement, soil concretion, diatomite and an additive in a proportion of 100: (3-6): (11-15): (9-21): (3-7) in a mass ratio.

2. The low shrinkage cement stabilized soil as claimed in claim 1, wherein: the cement stabilized soil is prepared from the following raw materials of soil, cement, soil concretion, diatomite and an additive in a proportion of 100: (4-6): (11-15): (9-18): (3-6) in a certain mass ratio.

3. The low shrinkage cement stabilized soil as claimed in claim 1, wherein: the soil concretion rock is prepared by mixing red mud, steel slag and phosphogypsum in a proportion of 5: (3-4): (1-2) in a certain mass ratio.

4. The low shrinkage cement stabilized soil as claimed in claim 1, wherein: the diatomite is modified diatomite by the following method:

(1) putting the diatomite to be treated into a container, adding a strong acid solution with the volume concentration of 10-15% into the container, and stirring and heating for 1-2h at the temperature of 80-90 ℃; (2) washing to be neutral.

5. The low shrinkage cement stabilized soil as claimed in claim 4, wherein: the modification method of the modified diatomite further comprises the step of soaking the diatomite washed to be neutral in an organic resin solvent with the mass concentration of 1-3% for 3-4h to obtain the modified diatomite.

6. The low shrinkage cement stabilized soil as claimed in claim 5, wherein: the organic resin is PVB resin; the solvent is ethanol.

7. The low shrinkage cement stabilized soil of claim 6, wherein: the additive is prepared from polyvinyl alcohol, maleic anhydride, acetone and silane coupling agent (3-6): (1.2-2.3): and (3-4) the mass ratio of 1.

8. The low shrinkage cement stabilized soil of claim 7, wherein: the additive is mainly prepared from polyvinyl alcohol, maleic anhydride, acetone, a silane coupling agent and polypropylene fibers in a weight ratio of (3-6): (1.2-2.3): (3-4): 1: (0.6-0.8) in mass ratio.

Technical Field

The application relates to the field of roadbed materials, in particular to low-shrinkage cement stabilized soil.

Background

In recent years, in the construction of high-grade roads in China, 80-90% of asphalt pavements are made of semi-rigid base courses, wherein 95% of asphalt pavements are made of base courses which are boards formed by inorganic binders, broken stones, soil and the like and have certain bending strength, and the base courses comprise cement stabilized soil, lime stabilized soil, industrial waste residue stabilized soil and the like. The cement stabilized soil is a type commonly used for semi-rigid base layers, has higher rigidity, better compressive strength and bending tensile strength, simultaneously has good water stability and stronger load diffusion capacity, ensures that the bending tensile stress value of an asphalt surface layer is smaller, meets the requirement of the asphalt pavement base layer, has low manufacturing cost and has better economy.

The strength of the cement stabilized soil layer is gradually attenuated by repeated dry-wet cycles and freeze-thaw cycles caused by natural environment, and the repeated dry-wet cycles caused by environment easily cause the cement stabilized soil layer to generate a drying shrinkage effect, so that shrinkage cracks are generated, and the asphalt pavement is reflected to generate reflection cracks to cause pavement cracking, so that the reduction of the drying shrinkage performance of the cement stabilized soil layer is an important measure for prolonging the service life of the asphalt pavement.

Disclosure of Invention

In order to reduce the drying shrinkage performance of cement stabilized soil layers, the application provides a low shrinkage cement stabilized soil.

The application provides a low shrink cement stabilized soil adopts following technical scheme:

the low-shrinkage cement stabilized soil is prepared from the following raw materials of soil, cement, cemented rock, diatomite and an additive, wherein the raw materials are as follows: (3-6): (11-15): (9-21): (3-7) in a mass ratio.

Preferably, the raw materials of the cement-stabilized soil mainly comprise soil, cement, tuff, diatomite and an additive, wherein the weight ratio of 100: (4-6): (11-15): (9-18): (3-6) in a certain mass ratio.

Through adopting above-mentioned technical scheme, cement, the soil concretion, the cooperation of diatomaceous earth and additive is used, can effectively reduce the shrinkage performance on soil horizon, its reason probably is cement, the soil concretion takes place the volcanic ash reaction with the soil granule and fixes the free water in the soil, needle crystal solid ettringite can be generated to this process, the hole between the soil granule is filled to the ettringite crystal that the reaction generated, make cement stabilized soil more closely knit, reduce the amount of drying shrinkage in cement stabilized soil layer later stage, thereby reduce the probability that cement stabilized soil layer ftractures, needle-like ettringite gel dispersion is around the soil granule simultaneously, and connect into one piece, reinforcing cement stabilized soil layer intensity.

The admixture is used with the cooperation of diatomaceous earth, can release partial moisture, make cement, the hydration reaction of soil concretion rock more abundant, effectively fill the hole in the cement stabilized soil layer, make the compactness of cement stabilized soil show and increase, possess stable bearing structure, and do not have the existence of cavity, space on the whole, show that the hydration product that lasts the production can enter into inside through soil particle surface, play the skeleton supporting role, promote the holistic mechanical properties in cement stabilized soil layer and promote to some extent.

Preferably, the soil-setting rock is prepared by mixing red mud, steel slag and phosphogypsum in a weight ratio of 5: (3-4): (1-2) in a certain mass ratio.

By adopting the technical scheme, the red mud, the steel slag and the phosphogypsum in the cemented rock are as follows: (3-4): after the mass ratio of (1-2) is mixed, the specific surface area of the cemented rock is 3100-³In the range of/g, the concrete can fully perform hydration reaction with cement and the like, and the shrinkage of a cement stabilized soil layer is reduced, so that the anti-cracking performance of the cement stabilized soil roadbed layer is effectively improved₂And A1₂O₃And the like exist, and form a water-insoluble crystal structure in the cement stabilized soil sample, so that the cement shrinkage phenomenon can be effectively reduced. And the red mud, the steel slag, the phosphogypsum and the like are subjected to hydration reaction and hydrolysis reaction under the action of water to generate hydrated calcium aluminate, calcium hydroxide and other gel hydrates, some hydrates are hardened to form a framework along with the reaction, some hydrates are bonded with soil particles under the action, and the gels are mutually connected to form a stable space network structure, so that the soil strength is improved.

Preferably, the diatomite is modified diatomite by the following method:

(1) putting the diatomite to be treated into a container, adding a strong acid solution with the volume concentration of 10-15% into the container, and stirring and heating for 1-2h at the temperature of 80-90 ℃;

(2) washing to be neutral.

By adopting the technical scheme, after the diatomite and the strong acid solution are stirred and mixed, the strong acid solution enters the porous of the diatomite and reacts with some components in the diatomite, so that the surface area of the diatomite is increased, more water can be absorbed, water can be released in the cement hydration process, and the phenomenon of shrinkage and cracking of the concrete caused by natural environment is reduced.

Preferably, the modified diatomite modification method further comprises the step of soaking the diatomite washed to be neutral in an organic resin solvent with the mass concentration of 1-3% for 3-4h to obtain the modified diatomite.

By adopting the technical scheme, after neutral diatomite is soaked in the organic resin solvent, the organic resin permeates into the pores of the diatomite and forms a film, a certain plugging effect is achieved on the porous structure of the diatomite, and the phenomenon that water in the diatomite flows out in the early construction stage is reduced, so that the water content in the diatomite can be continuously seeped out in the later stage to participate in the hydration reaction of cement, and the strength and the cracking resistance of a cement stabilized soil layer are improved.

Preferably, the organic resin is a PVB resin; the solvent is ethanol.

Preferably, the additive mainly comprises polyvinyl alcohol, maleic anhydride, acetone and a silane coupling agent, wherein the weight ratio of the polyvinyl alcohol to the maleic anhydride to the acetone is (3-6): (1.2-2.3): and (3-4) the mass ratio of 1.

By adopting the technical scheme, the polyvinyl alcohol, the maleic anhydride, the acetone and the silane coupling agent are mixed in a ratio of (3-6): (1.2-2.3): and (3-4) after the admixture is compounded according to the mass ratio of 1, sufficient water is provided for the later hydration of cement, the anti-cracking performance of the cement stabilized soil layer is improved, and the strength of the cement stabilized layer is improved.

Preferably, the additive mainly comprises polyvinyl alcohol, maleic anhydride, acetone, a silane coupling agent and polypropylene fibers, wherein the weight ratio of the polyvinyl alcohol to the maleic anhydride to the acetone is (3-6): (1.2-2.3): (3-4): 1: (0.6-0.8) in mass ratio.

Through adopting above-mentioned technical scheme, along with the going on of hydration reaction, the closely knit degree of cement stabilized soil layer increases, the inside crystalline solid that generates of cement stabilized soil also can constantly increase simultaneously, the hole is further crowded densely between the mixture, and polypropylene fiber's addition for polypropylene fiber forms network anchor structure with soil granule, slag, gelatins such as cement, the interparticle friction and cementation have been strengthened, the deformation of soil granule has effectively been retrained, thereby play certain constraint effect to the expansion of the crazing line of soil stabilized soil layer, thereby effectively reduce the anti fracture performance of cement stabilized soil layer.

When the content of the polypropylene fiber is low, the fibers and the fibers cannot form cross-linking overlapping, the contribution of the polypropylene fiber to the cement stabilized soil mainly takes the frictional resistance among reinforcing particles as a main part, when the content of the polypropylene fiber is too high, the distribution uniformity of the polypropylene fiber among the mixture is extremely difficult to control, the stirring and squeezing phenomenon is easily formed among the polypropylene fibers, the cross-linking embedding and squeezing effect of the fibers on the mixture is reduced, and therefore the compression strength of the cement stabilized soil can be effectively improved by the proportion of the polypropylene fiber in the additive.

In summary, the present application has the following beneficial effects:

1. the cement, the soil concretion, the additive and the like are used in a matching way, so that water can be provided for the continuous hydration of the cement, and the anti-cracking performance of the cement stabilized soil layer is reduced;

2. modified diatomaceous earth and polyvinyl alcohol, silane coupling agent, polypropylene fiber's cooperation is used for the inside hole of cement stabilized soil layer is crowded densely gradually, simultaneously when the polyvinyl alcohol after the release water in later stage, the release of moisture can make the soil layer inside take place further cross-linking and inlay crowded effect in the modified diatomaceous earth, thereby reduce the hole in the cement stabilized soil layer, and polypropylene fiber's restraint, effectively improve the anti fracture performance of cement stabilized soil layer, also can effectively improve the intensity of cement stabilized soil layer simultaneously.

Detailed Description

The present application will be described in further detail with reference to examples.

The cement is ordinary portland cement P.O 42.5.5 available from Jinbeijidong cement (Tangshan) Co.Ltd;

the diatomite is purchased from Hubei Jiujiu mineral products Co., Ltd, and the performance parameters of the diatomite are as follows: the density is 1.9-2.3g/cm³The specific surface area is 40-65m²Per g, pore volume 0.45-0.98cm³/g；

Polyvinyl alcohol is purchased from Henan reputations chemical Co., Ltd, and has a model number of L088-20;

the polypropylene fiber is purchased from Gallery crane flying building materials Co., Ltd, and the fiber length is 1.5-200 mm;

the soil of the application adopts fine-grained soil;

the soil concretion rock is formed by mixing red mud, steel slag and phosphogypsum, and the performance of the mixed soil concretion rock is as follows:

soil concretion rock performance parameter table

Preparation example 1

A preparation method of modified diatomite comprises the following steps:

(1) putting 90kg of diatomite to be treated into a container, adding a sulfuric acid solution with the volume concentration of 10-15% into the container, and stirring and heating for 1h at the temperature of 80-90 ℃;

(2) washing to be neutral.

Preparation example 2

A preparation method of modified diatomite comprises the following steps:

(1) putting 90kg of diatomite to be treated into a container, adding a sulfuric acid solution with the volume concentration of 15% into the container, and stirring and heating for 2 hours at the temperature of 90 ℃;

(2) washing to be neutral.

Preparation example 3

A preparation method of modified diatomite comprises the following steps:

(1) putting 90kg of diatomite to be treated into a container, adding a sulfuric acid solution with the volume concentration of 15% into the container, and stirring and heating for 2 hours at the temperature of 90 ℃;

(2) and (3) washing to be neutral, and soaking the neutral kieselguhr in a PVB ethanol solution with the mass concentration of 1% for 3 hours to obtain the modified kieselguhr.

Preparation example 4

A preparation method of modified diatomite comprises the following steps:

(1) putting 90kg of diatomite to be treated into a container, adding a sulfuric acid solution with the volume concentration of 15% into the container, and stirring and heating for 2 hours at the temperature of 90 ℃;

(2) and (3) washing to be neutral, and soaking the neutral kieselguhr in a PVB ethanol solution with the mass concentration of 3% for 4 hours to obtain the modified kieselguhr.

The formulation ratios of the anti-cracking cement stabilized soils of examples 1-9 are shown in Table 1, and the materials of examples 1-9 were mixed and mixed with water in an amount of 18% of the total amount of the materials.

Table 1 examples 1-9 cement stabilized soil proportioning table units: kg of

Example 10

A low shrinkage cement stabilized soil is different from that of example 7 in that the total amount of the admixture is unchanged, but the silane coupling agent is absent in the admixture, and the rest of the components in the admixture are 25kg of polyvinyl alcohol, 10kg of maleic anhydride and 25kg of acetone.

Example 11

A low-shrinkage cement stabilized soil is different from that in example 7 in that the mass ratio of polyvinyl alcohol, maleic anhydride, acetone and a silane coupling agent in an additive is 6:2.3:4:1, the specific amount of each component is 27.1kg of polyvinyl alcohol, 10.4kg of maleic anhydride, 18kg of acetone and 4.5kg of the silane coupling agent, and the rest is unchanged.

Example 12

A low-shrinkage cement stabilized soil is different from the cement stabilized soil in the embodiment 7 in that the total amount of an additive is unchanged, and polypropylene fibers are added into the additive, and the cement stabilized soil comprises the following components in percentage by weight: 20.5kg of polyvinyl alcohol, 8.2kg of maleic anhydride, 20.5kg of acetone, 6.8kg of silane coupling agent and 4kg of polypropylene fiber, and the rest of the components are the same as those in example 7.

Example 13

A low-shrinkage cement stabilized soil is different from the cement stabilized soil in the embodiment 7 in that the total amount of an additive is unchanged, and polypropylene fibers are added into the additive, and the cement stabilized soil comprises the following components in percentage by weight: 20kg of polyvinyl alcohol, 8kg of maleic anhydride, 20kg of acetone, 6.7kg of silane coupling agent and 5.3kg of polypropylene fiber, and the balance of the components is the same as in example 7.

Example 14

A low-shrinkage cement-stabilized soil which is different from that of example 11 in that the diatomaceous earth obtained in preparation example 1 was used as the diatomaceous earth, and the balance was the same.

Example 15

A low-shrinkage cement-stabilized soil was obtained as a diatomaceous earth obtained in preparation example 2, except that the diatomaceous earth used in example 11 was the same as the above diatomaceous earth.

Example 16

A low-shrinkage cement-stabilized soil which is different from that of example 11 in that the diatomaceous earth obtained in preparation example 3 was used as the diatomaceous earth, and the balance was the same.

Example 17

A low-shrinkage cement-stabilized soil which is different from that of example 11 in that the diatomaceous earth obtained in preparation example 4 was used as the diatomaceous earth, and the balance was not changed.

Comparative example 1

The difference from example 7 is that the cement stabilized soil material is free of diatomaceous earth and the balance is unchanged.

Comparative example 2

The difference from example 7 is that the cement stabilized soil raw material is free of admixture and the remainder is unchanged.

Comparative example

The cement stabilized soil was formed by mixing 1000kg of soil, 6kg of cement and 181kg of water.

Performance detection

The cement stabilized soils obtained in examples 1 to 17, comparative examples 1 to 2 and comparative example were subjected to unconfined compressive strength and shrinkage tests according to JTG E51-2009 test Specification for inorganic binder stabilizing materials for road engineering, and the test results are shown in the following tables.

TABLE 2 examples and comparative examples Cement stabilized soil drying shrinkage Properties

TABLE 3 table of strength properties of cement stabilized soils of examples and comparative examples

After the content of the soil concretion is increased on the basis of the example 1, as can be seen from table 2, the shrinkage of the cement stabilized soil in the example 2 in the early stage is reduced compared with the example 1, but the shrinkage and the water loss rate of the cement stabilized soil in 28 days are not greatly changed compared with the shrinkage and the water loss rate in the example 1, which may be caused by that red mud, steel slag and the like participate in the hydration reaction of the cement together with the cement to generate crystals insoluble in water and reduce the shrinkage in the early stage, and meanwhile, the increase of the soil concretion can improve the strength of the cement stabilized soil by combining the data in table 3;

after the contents of the tufa and the diatomite are increased on the basis of the embodiment 1, the shrinkage and the water loss rate of the cement stabilized soil in the early stage and the later stage are both reduced in the embodiment 3 compared with the embodiment 1, and mainly, water contained in the diatomite is slowly released in the middle and later stages, so that cement, red mud, steel slag and the like are fully reacted, and the shrinkage of the cement stabilized soil layer is reduced, and meanwhile, as can be seen from the table 3, after the tufa and the diatomite are simultaneously increased, the strength of the cement stabilized soil layer is also increased, probably because the hydration reaction is full, a plurality of gaps in the cement stabilized soil layer are filled, and the compactness of the cement stabilized soil layer is improved, so that the strength of the cement stabilized soil layer is improved;

after the soil concretion and the additive are added, the drying shrinkage and the water loss rate of the soil in the embodiment 4 are reduced compared with those of the soil in the embodiment 1, but the influence on the early stage of the cement stabilized soil is small, the influence on the later stage of the cement stabilized soil is large, and the stored water is released mainly due to the combination of the polyvinyl alcohol, the silane coupling agent and the diatomite, so that the hydration reaction is more sufficient, the drying shrinkage in the later stage is reduced, and the strength of the cement stabilized soil layer is also improved;

when the amounts of cement, soil aggregate and admixture were increased simultaneously, the dry shrinkage and water loss rate in example 5 were lower than those in example 1, and the strength of cement-stabilized soil was also increased as compared with example 1;

after the cement, the tuff, the diatomite and the additive are all increased, the dry shrinkage and the water loss rate of the concrete in the examples 6-8 are all reduced compared with the concrete in the example 1, and the dry shrinkage and the water loss rate of the concrete in the examples 6-8 are also lower than those of the concrete in the examples 2-5, so that when the cement, the tuff, the diatomite and the additive are cooperatively blended, the early-stage and later-stage dry shrinkage conditions are well improved, and meanwhile, the cement stabilizing soil in the example 8 is higher than that in the example 7 in content as seen in the examples 6-8, but the dry shrinkage and the water loss rate are not obviously reduced, and the strength of the cement stabilizing soil in the example 7 is also improved compared with that in the example 2 as seen in the table 3, so that the proportioning in the example 7 is better equipment;

in example 9, when the contents of the respective components in the soil aggregate were changed, the drying shrinkage and the water loss rate of the cement-stabilized soil of example 9 were not much changed from those of example 7, but the strength of the cement-stabilized soil was improved from that of example 7, as compared with example 7;

compared with the example 7, after the silane coupling agent is absent in the additive, the drying shrinkage and the water loss rate of the cement stabilized soil at the early stage and the later stage are increased, which shows that the drying shrinkage performance of the cement stabilized soil of the example 10 is poor, and therefore, the addition of the silane coupling agent can effectively improve the drying shrinkage performance of the cement stabilized soil, so that the cracking resistance of concrete is improved;

when the total amount of the admixture in example 11 is not changed, and the proportions of the components in the admixture are changed, the influence on the early-stage drying shrinkage and water loss rate of a cement stabilized soil layer is small, but the later-stage drying shrinkage performance of concrete can be improved, and the effect of low shrinkage is achieved;

compared with the example 7, after the polypropylene fibers are added into the admixture, the admixture has little influence on the early-stage drying shrinkage and water loss rate of the cement stabilized soil, and mainly can reduce the later-stage drying shrinkage and water loss rate of the cement stabilized soil, and meanwhile, as can be seen from the table 3, the strength of the cement stabilized soil in the examples 11 and 12 is higher than that of the cement stabilized soil in the example 7, the reason for the influence is that the polypropylene fibers can effectively restrict the deformation of cement stabilized soil particles, reduce the particle gaps among the mixture materials, form a whole of cross-linking embedding extrusion, and meanwhile, the network anchoring structure formed by the polypropylene fibers plays a certain restriction role in the later-stage deformation of the soil particles, and simultaneously, the network structure can also increase the strength of the cement stabilized soil;

in examples 14 to 17, compared with example 11, after the diatomaceous earth is pretreated with the diatomaceous earth, the early and later drying shrinkage and water loss rates of the cement stabilized soil in examples 14 to 17 are reduced, and the compressive strength is also obviously improved, which may be because, after the diatomaceous earth is pretreated, the diatomaceous earth slowly releases water, so that the later hydration reaction of cement and red mud steel slag is more sufficient, pores in concrete are compensated, and the anti-cracking performance and strength of concrete are improved;

compared with the example 7, the dry shrinkage, the water loss rate and the strength of the comparative examples 1-2 are lower than those of the example 7, and therefore, the shrinkage performance of the cement stabilized soil can be effectively improved and the strength of the cement stabilized soil can be improved by matching the diatomite and the additive with the cement and the clay concretion in the application.

The embodiments of the present invention are preferred embodiments of the present application, and the scope of protection of the present application is not limited by the embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.