Preparation And Mechanical Properties Of Ultrafine Ore Fine Cement Soil

In this paper,a large amount of ultrafine mineral powder is used to replace part of the cement,and the ultrafine mineral powder with cement are compounded into the clay to act as a curing agent,and Ca(OH)2 is added as an activator of the ultrafine mineral powder.Inspire the activity of ultrafine mineral powder,and strive to formulate a new material with good mechanical properties and durability,so as to be applied in engineering practice.And study the effect of cement and ultrafine mineral powder on the mechanical properties and durability of cement soilOn the basis of summarizing the application status and application prospects of ultrafine mineral powder materials in cement-based materials,this paper first analyzes the chemical constituents of ultrafine mineral powders;Through the indoor mechanical properties test of cement soil,the influence law of cement dosage,age and curing conditions on cement soil was discussed;Analysis of the effect of superfine ore powder content and curing age on ultrafine slag cement soil under the condition of 10%solidification agent;The orthogonal test method is adopted to prepare high-strength cement soil materials by the law of the factors affecting the cement soil by various factors;The anti-freeze and Na2SO4 corrosion tests were carried out on the prepared ultrafine slag cement soil.The effects of NA2SO4 concentration on the mechanical properties of ultrafine slag cement soil were investigated by unconfined compressive strength and stress-strain experiments;The solidified structure of cemented soil was analyzed by scanning electron microscopy.The composition of cement-soil produced by sodium sulphate was studied by XRD method.The ultra-fine mineral powder in cement water was discussed from the aspects of cement hydration and microstructure improvement.The mechanism of action during the hardening process.The study shows:The unconfined compressive strength of cemented soil increases with the increase of cement content and curing age;the compressive strength of cement soil under water conservation is lower than that under standard curing;With the increase of superfine ore powder substitution rate,the unconfined compressive strength of ultrafine slag cement soil decreases,but the percentage of decline gradually decreases.When the substitution rate of ultrafine slag is 80%,the maintenance is 7d.The intensity of the time decreased by 29%,while the strength of the 14d and 28d was increased by 9.3%and 15%;The increase of cement content can change the elastic modulus of cement soil and increase the peak stress of cement soil and ultrafine slag cement soil;When the freeze-thaw cycle is 15 times,the unconfined compressive strength loss rate of cement soil with 5%cement content is 68%.Then,with the increase of cement content,the compressive strength loss rate of cement soil decreases.In the 10%to 15%interval,the strength tends to be stable.When frozen and thawed 5 times,the compressive strength loss of ultrafine slag cement soil is very serious.When it freezes and thaws 15 times,its strength shows an upward trend;With the increase of sodium sulfate concentration,the compressive strength of ultrafine slag cement soil decreased first and then increased.When the concentration of sodium sulphate was 9g.L-1,the strength of the test piece increased by 42%.As the sodium concentration increases,the strength of the test piece shows a downward trend;The ultra-fine slag cement soil increased with the corrosion time of sodium sulfate,and the growth of 14d-28d was stronger than that of 28d?60d.At a concentration of 1.5g.L-1 of sodium sulfate,the cement soil first reached the peak stress;The surface of the cement soil sample in clear water is sparse,the grain size is obvious,and the surface of the sample with 22.5g.L-1 sodium sulfate concentration has slight crack formation,which may be due to the volume expansion force generated by the acicular ettringite;When the concentration of sodium sulfate is 22.5g.L-1,the diffraction peak of CaSiO3 appears,and the peak of CaCO3 is increased,indicating that SO42-can promote the reaction to form CaSiO3 and CaCO3.