Method of adjusting expanding property of black cotton soil

A technology of black cotton soil and expansiveness, which is applied in the field of adjusting the expansiveness of black cotton soil, and can solve the problems of failing to meet engineering mechanics standards and other problems.

Active Publication Date: 2017-12-26
CHINA ROAD & BRIDGE +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although replacement can solve the problem of road construction to a certain extent, the replaced soil will be stored in the designated site as industrial waste, which will bring a series of problems: the excavated soil needs a...

Method used

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  • Method of adjusting expanding property of black cotton soil
  • Method of adjusting expanding property of black cotton soil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] The original black cotton soil is directly grafted with silane

[0066] 1. Hydrolysis of silane: Add silane coupling agent with a volume fraction of 0.5% to 100mL of ethanol / water (9:1 by volume) mixed solution, adjust the pH value between 4-5 with glacial acetic acid, To promote hydrolysis, stir magnetically at room temperature for 1 hour.

[0067] 2. Surface grafting of black cotton soil: Disperse 15g of black cotton soil in a mixed solution of 100ml ethanol / water (9:1 by volume), put it in a beaker and stir until it is evenly dispersed to form a stable suspension. The silane solution was slowly dropped into the suspension. 70°C water bath for 4 hours. After the reaction, filter with suction, wash until neutral, and dry in an oven at 80°C for 12 hours; grind in a mortar for later use, and obtain a black cotton soil sample grafted with silane.

[0068] The measured free expansion rate is 120%.

Embodiment 2

[0070] The original black cotton soil is directly grafted with silane

[0071] 1. Hydrolysis of silane: Add 1% silane coupling agent by volume fraction to the mixed solution of 100mL ethanol / water (9:1 by volume), and adjust the pH value between 4-5 with glacial acetic acid to promote Hydrolyze, and magnetically stir for 1 hour at room temperature.

[0072] 2. Surface grafting of black cotton soil: Disperse 15g of black cotton soil in a mixed solution of 100mL ethanol / water (9:1 by volume), put it in a beaker and stir it magnetically, and wait until it is evenly dispersed to form a stable suspension. Slowly drop the silane solution into the suspension, and put it in a water bath at 70°C for 4 hours; after the reaction, filter it with suction, wash until it is neutral, dry it in an oven at 80°C for 12 hours, and grind it finely in a mortar for later use to obtain silane-grafted black cotton soil sample.

[0073] The free expansion rate was determined to be 61%.

Embodiment 3

[0075] The original black cotton soil is directly grafted with silane

[0076] 1. The hydrolysis of silane: the silane coupling agent that volume fraction is 2% is added in the mixed solution of 100mL ethanol / water (volume ratio is 9:1), adjust pH value between 4-5 with glacial acetic acid, promote Hydrolyze, and magnetically stir for 1 hour at room temperature.

[0077] 2. Surface grafting of black cotton soil: Disperse 15g of black cotton soil in a mixed solution of 100mL ethanol / water (9:1 by volume), put it in a beaker and stir it magnetically, and wait until it is evenly dispersed to form a stable suspension. Slowly drop the silane solution into the suspension, and put it in a water bath at 70°C for 4 hours; after the reaction, filter it with suction, wash until it is neutral, dry it in an oven at 80°C for 12 hours, and grind it finely in a mortar for later use to obtain silane-grafted black cotton soil sample.

[0078] The measured free expansion rate was 41%.

[0079...

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Abstract

The invention provides a method of adjusting the expanding property of black cotton soil. The method comprises the following steps: preprocessing black cotton soil to obtain a black cotton soil sample, wherein the pretreatment comprises an acidification treatment and a sodium pillaring treatment; subjecting silane to hydrolysis to obtain a silane hydrolysis solution; and using the silane hydrolysis solution to carry out silane grafting on preprocessed black cotton soil to obtain a silane grafted black cotton soil sample. According to the provided method, black cotton soil is subjected to an acidification or sodium modification pretreatment to obtain black cotton soil with certain activity; then the black cotton soil is grafted by silane with different concentrations, silane and hydroxyl groups in the black cotton soil carry out condensation reactions, the hydrophilic property of black cotton soil is converted into hydrophobic property, and the water absorbing expanding property of black cotton soil is changed.

Description

technical field [0001] The invention relates to the field of building materials, in particular to a method for adjusting the expansibility of black cotton soil. Background technique [0002] As a kind of highly hydrated clay with high expansibility, black cotton soil is widely distributed all over the world. The main mineral component of black cotton soil is montmorillonite, which is a kind of highly plastic clay, which swells when exposed to water and shrinks when it loses water. swell. When the soil loses water, the bound water film becomes thinner, and the distance between particles shrinks, causing the volume to shrink. While absorbing water and shrinking when losing water, the mechanical properties will decrease a lot accordingly. For example: Located in the central and eastern regions of Africa, it belongs to the tropical monsoon climate with alternating dry and rainy seasons. In the dry season, the precipitation is less, and the black cotton soil is in a cemented ...

Claims

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Application Information

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IPC IPC(8): C01B33/40
CPCC01B33/40
Inventor 苗世顶黄金秋张培萍张鹏王健沈兆普
Owner CHINA ROAD & BRIDGE
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