CN101255043B

CN101255043B - Modifier for road engineering filling

Info

Publication number: CN101255043B
Application number: CN2007101920063A
Authority: CN
Inventors: 解建光; 刘文荣; 虞国俊; 黄永铭; 季小明; 耿飞; 袁劲华; 计梁; 焦振寿; 徐贤明; 仲曙豪; 曹兴国; 杨朝旭
Original assignee: JIANGSU CHANGZHOU SEA-ROUTE MANAGEMENT BUREAU; Nanjing University of Aeronautics and Astronautics
Current assignee: JIANGSU CHANGZHOU SEA-ROUTE MANAGEMENT BUREAU; Nanjing University of Aeronautics and Astronautics
Priority date: 2007-12-28
Filing date: 2007-12-28
Publication date: 2010-06-16
Anticipated expiration: 2027-12-28
Also published as: CN101255043A

Abstract

A highway project filling modifier formula is characterized in that the weight percentage of formula ingredients is: 8%-16% of silicate cement; 8%-18% of waster alkaline residue from the ammonia-sodaproduction process and 70%-84% of abandoned concrete. The invention uses waster alkaline residue and abandoned concrete as the modifier components while using low doses of cement at the same time so that utilizing not only the cement strength formed by hydration solidification, but also the improved comprehensive strength formed in alkaline residue reacting with soil composition and cement and utilizing the waste concrete to provide a skeleton and reducing shrinkage cracking of the modified soil.

Description

A kind of properties-correcting agent of road engineering fill

One, technical field

The invention belongs to a kind of chemical composition properties-correcting agent, particularly a kind of formula of modifier that non-suitable land reform is banketed as highway.

Two, background technology

Prior art: the earthwork that the transportation industry development need is a large amount of; be suitable for soil at present and be mainly derived from arable land along the line; cause the good farmland to reduce and environmental disruption; so patent is banketed as road base layer with non-suitable soil (mucky soil, aleuritic texture soil etc.) modification, the contradiction between transport solution construction and land resources are in short supply realizes the comprehensive utilization of the earthwork; reach simultaneously and turn harm into good; turn waste into wealth, realize the recycling of non-suitable soil, the protection environment.

At present, mud matter, the non-suitable cubic metre of earth main way of aleuritic texture soil are part admixture cement or the unslaked lime improvement soil properties good slightly to soil property, are used modestly on a small quantity.The part relatively poor for soil property then is considered as discommodity, abandons arbitrarily.

The silt clay content is few, water content is higher, specific surface area is little and chemically reactive is low, itself does not have gelling ability substantially, soil strength mainly is made of intergranular inner frictional resistance, mechanical strength is low and consolidation effect is relatively poor, and bad engineering properties is having a strong impact on the quality of highway subgrade pavement engineering.

Mud and mucky soil, the water content height, the organic content height, hole is bigger, soil property weakness, slip resistance are very low, and discharging consolidation is slow, have thixotropy, easily cause foundation uneven settlement and roadbed basin shape unstability, directly, can have a strong impact on the road engineering quality as high-grade highway roadbed filler.

For a long time, China stablizes roadbase soil with cement, lime or cement-lime always, but all fails to obtain promising result technically and economically.The application of cement in modification soil is commonplace, and intensity that it is generally acknowledged modification soil improves with the increase of cement mixing content, but too high cement mixing content has not only increased cost, and modification soil drying shrinkage is increased, and be easy to crack.Lime powder compacted soil ([1] the Puppala Anand J that at home and abroad is applied, Mohammad Louay N, Allen Aaron.Engineering behavior oflime-treated louisiana subgrade soil[J] .Transportation Research Record, 1996,1546 (11): 24～31.[2] Cao Xiaojuan, Sun Mingzhi, Meng Xianyong. conditioned soil test of static strength and interpretation of result [J]. the engineering geology journal, 2004,12 (1): 109～112), but the cured body gain in strength of lime modified soil is slow, drying shrinkage is big, easy to crack, easily softening, water stability is poor.The stable patent that is suitable for native preparation engineering soil of domestic useful alkaline residue, patent [3] desiccating method is handled the method for producing engineering soil from alkaline slag, the patent No. 95108024.5 and [4] alkaline residue making engineering soil using and manufacture method and equipment, the patent No. 96109572.5 as main component preparation engineering soil, wherein adopts small part loess to mix and stir the compacting producing engineering soil as filler alkaline residue sometimes.Loess is the natural mixture of unstratified clay and mineral particles, and water content is low, lightweight and porous, and plasticity is better, is one of northern area main raw material of producing cement and clay brick.With the non-suitable soil such as mucky soil of water content height, plasticity difference very big difference is arranged.Loess is the filler that accounts for small portion in its patent formulation in addition, and is different fully with the know-why that adopts the stable a large amount of non-suitable soil of a small amount of alkaline residue among the present invention.At present there is not alkaline residue to be used for the patent and the open report of non-suitable soil such as non-silt, mucky soil both at home and abroad.Discarded concrete is used in the improvement earthwork and is not seen patent and open report as yet.

Three, summary of the invention

The present invention is directed to above-mentioned technological deficiency, use low dosage cement, alkaline residue and discarded concrete, non-suitable soil is carried out modification, can be used for High-Grade Highway Subgrade and banket simultaneously as formula of modifier.Solve traditional material intensity and form slow or problem such as shrinkage cracking is big, provide over-all properties good roadbed material.

Technical solution of the present invention is: the characteristic of three kinds of components and the content in properties-correcting agent are as follows:

Cement:

Ordinary Portland cement (as 32.5 grades or 42.5 grades), the content in prescription be 8-16% (mass percent, %).

Alkaline residue:

Alkaline residue is the waste of discharging in the solvay soda process production process, the content in prescription be 8-18% (mass percent, %).

The main component of table 1 alkaline residue (%)

Discarded concrete:

Discarded concrete is a building castoff, and main component is that Calucium Silicate powder, calcium hydroxide, the sour calcium of sulphur aluminium (iron) are molten admittedly, the sour calcium of aluminium (iron) etc. pulverized back use in this prescription with limestone or basalt aggregate with it, and its size distribution sees Table 2.

Table 2 discarded concrete size distribution

The content of discarded concrete in formula of modifier be 70-84% (mass percent, %)

Complicated physics, chemical reaction take place between water in cement and the non-suitable soil and the sludge granules, the fibrous hydrated calcium silicate CSH hydrated product of main formation, make soil body hole wall have globality and form skeleton structure, thereby improve the modification soil intensity after solidifying.Take place between alkaline residue and the soil flocculation agglomeration, with soil in active substance the generation pozzolanic action, produce crystallization and carboniogenesis etc. improving the intensity of modification soil, and combine formation " micro-aggregate " with a small amount of clay in the non-suitable soil and play the filling skeleton function.Simultaneously, alkaline residue and cement reaction generate and contain ettringite, and solid volume is increased, and further filling concrete cured product of the ettringite crystallization of pin column and native hole form good skeleton structure, have further increased the intensity of solidified earth.Discarded concrete particulate main component is that Calucium Silicate powder, calcium hydroxide, the sour calcium of sulphur aluminium (iron) are molten admittedly, the sour calcium of aluminium (iron) etc. and limestone or basalt aggregate.Can in modification soil, play the effect of gathering materials, improve the intensity of modification soil.In addition,, can enlarge to make non-suitable native water ratio scope, more help it and in engineering, use owing to discarded concrete has certain water-absorbent.Discarded concrete also has a more important role, because its dispersion in soil has reduced non-suitable native whole contraction, has improved the problem of non-suitable soil stabilization difference, and whole contraction is reduced, and stability improves.

Beneficial effect: the present invention is when using low dosage cement, use waste alkaline residue and discarded concrete to form as properties-correcting agent simultaneously, not only utilize hydrated cementitious to solidify the intensity of formation, also utilize the reaction of alkaline residue and local soil type's branch, cement that the raising of comprehensive strength is provided, utilize discarded concrete that skeleton function is provided, and reduce the shrinkage cracking of modification soil.The main ingredient that this prescription uses is industry or building castoff, has advantage on price, has good social benefit and environmental benefit.After in soil, mixing 25% properties-correcting agent, at maximum water holding capacity, require compacting under the compactness condition, unconfined compression strength, CBR and the shrinkage etc. of soil have obtained following effect: unconfined compression strength: silt is through behind this modifier modification, its 7 days unconfined compression strengths are brought up to greater than 0.30MPa from about 0.05MPa, and the amplitude that improved is 500～700%.And after its modification of silt soil process, its 7 days unconfined compression strengths have improved 100-200% from bringing up to less than 0.10MPa greater than 0.25MPa.CBR: silt is through behind the modifier modification, and its CBR is from bringing up to greater than 110% less than 20%, and increase rate is about 400-500%.And silt soil is through after its modification, and its CBR has improved 400% from bringing up to greater than 100% less than 20% through its intensity after the useless concrete modification.Shrinkability: non-suitable soil and traditional modified cement soil phase ratio, because the effect of shrinking is restrained in the adding, particularly discarded concrete particle of alkaline residue in soil, make modification soil when reaching identical unconfined compression strength, drying shrinkage can reduce more than 65% on year-on-year basis in 7 days.The discarded concrete particulate adds the shrinkage and the stability that can improve modification soil greatly, reduces the contraction of modification soil.Discarded concrete is seen Fig. 1 to the anti-effect of contraction of soil.

Four, description of drawings

Fig. 1 is the influence curve figure of discarded concrete to modification soil shrinkage energy.

Five, embodiment

The described content of following examples all refers to mass percent.

Embodiment 1:

Cement content is 16%, alkaline residue content is 18%, discarded concrete granule content 66%, incorporation with 25% is added in the non-suitable soil, add water and mix and stir to optimum moisture content, stir, requiring compacting under the compactness, unconfined compression strength, CBR reached 0.41MPa and 127% respectively in 7 days; And identical cement content modified cement soil (containing cement 4%) 7 days unconfined compression strengths, CBRs are respectively about 0.20MPa and 60%; The lime modified soil of 4% lime 7 days unconfined compression strengths, CBRs are respectively less than 0.08MPa and 30%.

Embodiment 2:

Cement content is 16%, alkaline residue content is 8%, discarded concrete granule content 76%, incorporation with 25% is added in the non-suitable soil, add water and mix and stir to optimum moisture content, stir, requiring compacting under the compactness, unconfined compression strength, CBR reached 0.35MPa and 110% respectively in 7 days; And identical cement content modified cement soil (containing cement 4%) 7 days unconfined compression strengths, CBRs are respectively about 0.20MPa and 60%; The lime modified soil of 4% lime 7 days unconfined compression strengths, CBRs are respectively less than 0.08MPa and 30%.

Embodiment 3:

Cement content is 10%, alkaline residue content is 10%, discarded concrete granule content 80%, incorporation with 25% is added in the non-suitable soil, add water and mix and stir to optimum moisture content, stir, requiring compacting under the compactness, unconfined compression strength, CBR reached 0.28MPa and 98% respectively in 7 days; And identical cement content modified cement soil (containing cement 2.5%) 7 days unconfined compression strengths, CBRs are respectively about 0.14MPa and 40%; The lime modified soil of 2.5% lime 7 days unconfined compression strengths, CBRs are respectively less than 0.05MPa and 25%.

Embodiment 4:

Cement content is 8%, alkaline residue content is 11%, discarded concrete granule content 81%, incorporation with 25% is added in the non-suitable soil, add water and mix and stir to optimum moisture content, stir, requiring compacting under the compactness, unconfined compression strength, CBR reached 0.25MPa and 90% respectively in 7 days; And identical cement content modified cement soil (containing cement 2.0%) 7 days unconfined compression strengths, CBRs are respectively about 0.10MPa and 30%; The lime modified soil of 2.0% lime 7 days unconfined compression strengths, CBRs are respectively less than 0.05MPa and 23%.

Embodiment 5:

Cement content is 8%, alkaline residue content is 8%, discarded concrete granule content 84%, incorporation with 25% is added in the non-suitable soil, add water and mix and stir to optimum moisture content, stir, requiring compacting under the compactness, unconfined compression strength, CBR reached 0.23MPa and 90% respectively in 7 days; And identical cement content modified cement soil (containing cement 2.0%) 7 days unconfined compression strengths, CBRs are respectively about 0.10MPa and 30%; The lime modified soil of 2.0% lime 7 days unconfined compression strengths, CBRs are respectively less than 0.05MPa and 23%.

Claims

1. the properties-correcting agent of a road engineering fill is characterized in that the mass percent composition of this prescription is:

Silicate cement, content are 8～16%; The waste alkaline residue of discharging in the solvay soda process production process, content are 8～18%; Discarded concrete, content are 70～84%.

2. the properties-correcting agent of road engineering fill as claimed in claim 1 is characterized in that described silicate cement is 32.5 grades or 42.5 grades.