Curing agent applied to soft soil foundation as well as preparation method and application of curing agent

Abstract

The invention provides a curing agent applied to a soft soil foundation and a preparation method and application thereof, and belongs to the technical field of building materials.The curing agent applied to the soft soil foundation is prepared from 85 parts of second-ball desulfurized fly ash, 5-7 parts of straw ash, 9-10 parts of alkaline residues, 1.5-2 parts of sodium aluminosilicate and 0.5-1 part of triethanolamine; the preparation method comprises the following steps: uniformly mixing a desulfurized fly ash pretreatment material, straw ash and sodium aluminosilicate to obtain a material A; uniformly mixing the alkaline residue pretreated material with triethanolamine to obtain a material B; the material A and the material B are jointly used as the curing agent applied to the soft soil foundation; according to the application, soft soil and the curing agent applied to the soft soil foundation are mixed through a solid stirring method, and then rolling and curing are conducted. By optimizing the raw material ratio and the preparation process, a substance with excellent gelling property and curing effect can be generated, and the strength and stability of the soft soil are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building materials, and particularly relates to a solidifying agent for soft soil foundation and a preparation method and application thereof. BACKGROUND

[0002] Soft soil foundation is widely used in construction, transportation and water conservancy engineering, and its characteristics of low strength, high compressibility and poor bearing capacity bring many challenges to various engineering construction. Although traditional soft soil foundation reinforcement methods such as replacement method, preloading method, surcharge preloading method, vacuum preloading method, dynamic compaction method and deep mixing method have certain effects, they have problems such as long construction period, high cost and great impact on the environment.

[0003] In the field of soft soil foundation treatment, solidifying agent technology has gradually attracted attention. Although the existing solidifying agent can improve the strength of soft soil to a certain extent, it has limitations, and most of them use cement as the main component, rely on natural mineral raw materials, consume a lot of resources and have high cost; at the same time, the improvement range of the strength of soft soil is limited, which is difficult to meet the demand for high strength; under complex geological and environmental conditions, the stability and adaptability are insufficient.

[0004] In addition, the existing solidifying agent preparation process is relatively simple, and the raw material ratio and process parameters are not fully optimized, resulting in insufficient utilization of active ingredients and poor solidification effect. At the same time, the resource utilization of waste is insufficient, and a large amount of industrial waste slag and biomass waste has not been effectively integrated, missing the opportunity to reduce cost and improve environmental benefits.

[0005] Therefore, it is a key requirement in the current soft soil foundation treatment field to develop a soft soil foundation solidifying agent based on waste resource utilization, with high performance, low cost and good environmental benefits, and a preparation method thereof. SUMMARY

[0006] In view of the above problems, the application provides a solidifying agent for soft soil foundation and a preparation method and application thereof.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0008] A solidifying agent for soft soil foundation, the raw materials for preparing the solidifying agent for soft soil foundation include, in parts by weight:

[0009] Desulfurized fly ash 85 parts, straw ash 5-7 parts, alkali residue 9-10 parts, sodium orthoaluminosilicate 1.5-2 parts and triethanolamine 0.5-1 part.

[0010] Further, the straw ash is obtained by calcining and ball milling corn stalks, and then soaking, washing, drying and crushing the obtained corn stalk ash with a citric acid aqueous solution.

[0011] Further, in the preparation process of the straw ash, the calcination temperature is 480-520 DEG C, and the time is 3.5-4.5h.

[0012] Further, in the preparation process of the straw ash, the concentration of citric acid in the aqueous solution of citric acid is 5-10wt%.

[0013] Further, in the preparation process of the straw ash, the soaking time is more than 12h.

[0014] Further, the particle size of the straw ash is 200-250 mesh.

[0015] A preparation method of the above-mentioned curing agent applied to soft soil foundation, the preparation method comprises the following steps:

[0016] The desulfurization ash and the alkali residue are taken and crushed respectively to obtain desulfurization ash pretreatment material and alkali residue pretreatment material;

[0017] The desulfurization ash pretreatment material, the straw ash and the sodium aluminosilicate are taken and uniformly mixed to obtain A material;

[0018] The alkali residue pretreatment material and the triethanolamine are taken and uniformly mixed to obtain B material;

[0019] The obtained A material and B material are jointly used as the curing agent applied to soft soil foundation.

[0020] Further, the particle size of the desulfurization ash pretreatment material and the alkali residue pretreatment material is 200-250 mesh.

[0021] Further, before use, the A material and the B material are uniformly mixed.

[0022] An application of the above-mentioned curing agent applied to soft soil foundation, the application is that the soft soil is mixed with the curing agent applied to soft soil foundation by solid stirring method, and then is rolled and maintained.

[0023] The curing agent applied to soft soil foundation, the preparation method and the application of the curing agent have the following beneficial effects:

[0024] The raw material ratio and the preparation process are optimized, so that the material with excellent gelation and curing effect can be generated, and the strength and stability of the soft soil are significantly improved; the preparation method not only realizes the resource utilization of waste residues and waste, but also has the advantages of high performance and low cost;

[0025] The straw ash prepared by the specific process is used, the content of amorphous silicon dioxide and the content of diatomic aluminum in the straw ash are improved by controlling the calcination temperature, and the impurities in the corn straw ash are reduced by cooperating with the modification of citric acid, so that the peak area of the calcium silicate hydrate generated by the secondary hydration reaction is improved, the Ca / Si ratio of the calcium silicate hydrate at the interface transition zone is reduced, the pore size is smaller, and the compressive strength is higher, so that the solidification capacity of the solidifying agent prepared in the later stage is improved;

[0026] The present application can generate calcium silicate hydrate (C-S-H) by secondary hydration reaction of calcium in the desulfurization ash and silicon dioxide, aluminum oxide and sodium aluminum silicate in the straw ash in the alkalinity environment provided by the alkali residue by selecting specific amounts of desulfurization ash and other components such as straw ash, thereby improving the soft soil solidification strength;

[0027] Further, in the alkali activation reaction process, the alkali residue and sodium aluminum silicate are used in cooperation to synergistically activate SiO2 and Al2O3 in the desulfurization ash and the straw ash, to generate calcium silicate hydrate (C-S-H gel) and calcium aluminate hydrate (C-A-H gel), which can further improve the cementation and solidification effect;

[0028] At the same time, the ions ionized from the straw ash also generate electrostatic attraction with the soil particles, the number of ions required to balance the negative charge on the surface of the soil particles is less, the thickness of the double electric layer of the soil particles is weakened, the distance between the soil particles is reduced, the soil particles are aggregated together, and the strength of the solidified soil is improved; at the same time, the alkalinity environment can also activate part of the silicon dioxide, diatomic aluminum and other activities in the soft soil, so as to participate in the secondary hydration reaction, and further improve the strength of the solidified soil.

[0029] And, Ca 2+ in the desulfurization ash + , K + in the soft soil BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a comparison chart of the influence of different straw ash amounts on the solidification results in the embodiment 6 of the present application;

[0031] Figure 2 is a comparison chart of the influence of different calcination processes on the solidification results in the embodiment 6 of the present application;

[0032] Figure 3 is a comparison chart of the influence of different soaking processes on the solidification results in the embodiment 6 of the present application;

[0033] Figure 4 is a comparison chart of the influence of different amounts of sodium aluminum silicate on the solidification results in the embodiment 6 of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application are clearly and completely described below. In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit and scope of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0035] Embodiment 1: a solidifying agent applied to soft soil foundation and a preparation method and application thereof

[0036] The present embodiment is a solidifying agent applied to soft soil foundation and a preparation method and application thereof, and the details are as follows:

[0037] I. Formula of the solidifying agent applied to soft soil foundation: two-ball desulfurization ash 85 kg, straw ash 6 kg, alkali residue 9.5 kg, sodium orthoaluminosilicate 2 kg, and triethanolamine 0.8 kg.

[0038] II. Preparation method of the solidifying agent applied to soft soil foundation

[0039] S1, take the two-ball desulfurization ash, ball mill, and pass through a 250-mesh sieve to obtain desulfurization ash pretreatment material;

[0040] S2, take the corn straw, place it in a muffle furnace and calcine at 500°C for 4h, after calcination is completed, cool, and then ball mill and crush to obtain corn straw ash;

[0041] The corn straw ash is soaked in a 5wt% citric acid aqueous solution for 12h, then washed and dried to constant weight, and then ball milled and passed through a 250-mesh sieve to obtain straw ash;

[0042] S3, take the alkali residue, ball mill, and pass through a 250-mesh sieve to obtain alkali residue pretreatment material;

[0043] S4, mix the desulfurization ash pretreatment material 85 kg, straw ash 6 kg, and sodium orthoaluminosilicate 2 kg uniformly to obtain 93 kg of A material;

[0044] S5, mix the alkali residue pretreatment material 9.5 kg and triethanolamine 0.8 kg uniformly to obtain 10.3 kg of B material.

[0045] S6, before use, mix the A material and the B material in a weight ratio of 93:10.3 to obtain the solidifying agent applied to soft soil foundation.

[0046] III. Use method of the solidifying agent applied to soft soil foundation (solid stirring method)

[0047] Take the soft soil with water content of 70%, remove large impurities, add 10% of the curing agent for soft soil foundation by weight, mix, dry material mixing for 3 minutes by forced mixer, then transport, paving, rolling, curing for 7 days and 28 days respectively. Among them, the 7-day unconfined compressive strength is 5.89 MPa, and the 28-day unconfined compressive strength is 7.93 MPa.

[0048] Examples 2-5 curing agent for soft soil foundation and its preparation method and application

[0049] Examples 2-5 are respectively a curing agent for soft soil foundation and its preparation method and application, according to the optimized formula given in Example 1, the scope of the curing agent for soft soil foundation and its preparation method and application is further explored, and the formula and preparation method in Examples 2-5 are obtained, wherein Examples 2-5 are basically the same as Example 1, the only difference is that some process parameters are different, for details, see Table 1:

[0050] Table 1 List of process parameters in Examples 2-5

[0051]

[0052]

[0053] The contents and results of other parts of Examples 2-5 are basically the same as those of Example 1, which will not be repeated here.

[0054] Example 6 Investigation of the influence of each process parameter in the preparation process of the curing agent for soft soil foundation on the application results

[0055] This example investigates the influence of each process parameter in the preparation process of the curing agent for soft soil foundation in Example 1 on the application results. In the investigation process, the preparation process of the curing agent for soft soil foundation is basically the same as that of the curing agent for soft soil foundation in Example 1, and the application of the curing agent for soft soil foundation is also the same as that of Example 1.

[0056] I. Investigation of the amount of straw ash

[0057] Take the straw ash prepared in Example 1, add different amounts of straw ash to prepare the corresponding curing agent for soft soil foundation (i.e. only change the amount of straw ash in Example 1, the amount of other raw materials and process conditions remain unchanged), and cure the soft soil with water content of 70% with each curing agent for soft soil foundation. Among them, the different amounts of straw ash are 0, 3, 6 and 12 kg, respectively, and the corresponding curing agent for soft soil foundation is prepared, and the soft soil with water content of 70% is cured, and after curing for 7 days and 28 days, the results are shown in Table 2 and Figure 1 .

[0058] Table 2: Effect of different amounts of straw ash on solidification

[0059] Straw ash amount (kg) 7-day average unconfined compressive strength (MPa) 28-day average unconfined compressive strength (MPa) 0 1.92 2.64 3 4.76 5.66 6 5.89 7.93 12 5.86 7.87

[0060] From Table 2 and Figure 1 It can be seen that the use of a specific amount of straw ash can effectively improve the solidification effect of the solidification agent used in soft soil foundation.

[0061] II. Investigation of straw ash preparation process

[0062] The same batch of corn straw was used to prepare straw ash using different calcination processes and soaking processes. Then, the respective solidification agents used in soft soil foundation were prepared using the straw ash (i.e., only the preparation process of the straw ash in Example 1 was changed, and the amounts of the straw ash and other raw materials and the process conditions for preparing the solidification agent used in soft soil foundation were unchanged). The respective solidification agents used in soft soil foundation were used to solidify soft soil with a water content of 70%. The different straw ash preparation process parameters and the solidification results of the respective solidification agents used in soft soil foundation are shown in Table 3-Table 4 and Figures 2-3 .

[0063] Table 3: Effect of different calcination processes on solidification

[0064]

[0065]

[0066] Table 4: Effect of different soaking processes on solidification

[0067] Soaking conditions 7-day average unconfined compressive strength (MPa) 28-day average unconfined compressive strength (MPa) 1 wt% citric acid aqueous solution for 12 h 3.24 4.57 1 wt% citric acid aqueous solution for 24 h 3.73 4.96 5 wt% citric acid aqueous solution for 6 h 5.07 6.82 5 wt% citric acid aqueous solution for 12 h 5.89 7.93 5 wt% citric acid aqueous solution for 24 h 5.88 7.94 10 wt% citric acid aqueous solution for 6 h 4.62 6.58 10 wt% citric acid aqueous solution for 12 h 5.82 7.89

[0068] From Table 3-Table 4 and Figures 2-3 It can be seen that changing the preparation process of the straw ash can affect the solidification effect of the solidification agent used in soft soil foundation, and specific calcination conditions and soaking conditions can effectively improve the solidification effect of the solidification agent used in soft soil foundation.

[0069] III. Investigation of the amount of sodium orthoaluminosilicate

[0070] Different amounts of sodium orthoaluminosilicate were added to prepare the respective solidification agents used in soft soil foundation (i.e., only the amount of sodium orthoaluminosilicate in Example 1 was changed, and the amounts of other raw materials and process conditions were unchanged). The respective solidification agents used in soft soil foundation were used to solidify soft soil with a water content of 70%. The different amounts of sodium orthoaluminosilicate were 0.2 kg, 2 kg, and 5 kg, respectively, and the respective solidification agents used in soft soil foundation were prepared. After 7 days and 28 days of curing, the results are shown in Table 5 and Figure 4 .

[0071] Table 5: Results of the influence of different amounts of sodium orthoaluminosilicate on the curing effect

[0072] Aluminum sodium silicate amount (kg) 7-day average unconfined compressive strength (MPa) 28-day average unconfined compressive strength (MPa) 0.2 3.92 5.17 2 5.89 7.93 4 5.31 7.04

[0073] From Table 5 and Figure 4 It can be seen that a specific amount of sodium orthoaluminosilicate can effectively improve the curing effect of the curing agent applied to the soft soil foundation.

[0074] Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

Claims

1. A solidifying agent for use in soft soil foundations, characterized in that, The raw materials for preparing the solidifying agent for soft soil foundations, by weight, include: The mixture consists of 85 parts of desulfurization ash from two spheres, 5-7 parts of straw ash, 9-10 parts of alkaline slag, 1.5-2 parts of sodium aluminosilicate, and 0.5-1 parts of triethanolamine.

2. The solidifying agent for soft soil foundations according to claim 1, characterized in that, The straw ash is obtained by calcining and ball milling corn stalks, followed by soaking, washing, drying, and pulverizing the resulting corn stalk ash in a citric acid aqueous solution.

3. The solidifying agent for soft soil foundations according to claim 2, characterized in that, In the process of preparing straw ash, the calcination temperature is 480-520℃ and the time is 3.5-4.5h.

4. The solidifying agent for soft soil foundations according to claim 2 or 3, characterized in that, In the preparation of straw ash, the concentration of citric acid in the citric acid aqueous solution is 5-10 wt%.

5. The solidifying agent for soft soil foundations according to claim 2 or 3, characterized in that, The soaking time for straw ash preparation is more than 12 hours.

6. The solidifying agent for soft soil foundations according to any one of claims 1-3, characterized in that, The particle size of straw ash is 200-250 mesh.

7. A method for preparing the solidifying agent for soft soil foundations according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: After crushing the desulfurization ash and alkali residue from the two balls respectively, desulfurization ash pretreatment material and alkali residue pretreatment material are obtained. Take desulfurization ash pretreatment material, straw ash and sodium aluminosilicate and mix them evenly to obtain material A; Take the alkaline residue pretreated material and triethanolamine, mix them evenly to obtain material B; The resulting material A and material B are used together as the solidifying agent applied to the soft soil foundation.

8. The method for preparing the solidifying agent for soft soil foundations according to claim 7, characterized in that, The particle size of both the desulfurization ash pretreatment material and the alkali slag pretreatment material is 200-250 mesh.

9. The method for preparing a solidifying agent for soft soil foundations according to claim 7 or 8, characterized in that, Before using the solidifying agent applied to soft soil foundations, mix component A and component B thoroughly.

10. The application of the solidifying agent according to any one of claims 1-6 to a soft soil foundation, characterized in that, The application involves mixing soft soil with the solidifying agent used for soft soil foundations using a solid mixing method, followed by compaction and curing.

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