Effect Of Mineral Admixture On Performance Of Interface Transition Zone And Pore Structure Of Concrete

Concrete is a kind of a heterogeneous composite material,which can be divided into cement stone,aggregate and interface transition zone.For ordinary concrete,part of the interface transition zone is weaker than the other two components,affecting the mechanical properties and durability of the concrete.At the same time,the porosity,pore size distribution and other pore structure parameters of the cement stone also affect the durability of the concrete.Due to its pozzolanic effect,micro-aggregate effect and morphological effect,mineral admixtures have a certain impact on the durability and mechanical properties of concrete.This article mainly explores the effect of admixtures on the interface properties of concrete and its effect on the pore structure of cement stone.The common fly ash,silica fume and two different fineness slags were chosen as research objects to study the effect of the type and amount of admixtures on the interfacial properties of concrete and the pore structure of cement stone,and compare the results of the research with its impact on compressive strength.The results of the study showed that the fly ash was incorporated to reduce the early compressive strength of the concrete,the content was more than 20%,and the compressive strength at 28 days decreased.The incorporation of slag with a specific surface area of 400 m2/kg does not improve the early strength of the concrete.The compressive strength at 28 days increases when the amount of slag does not exceed 30%.After adding 1000m2/kg slag,the compressive strength of 28 d can be increased.When the blending amount is less than 30%,the early compressive strength is improved.The incorporation of silica fume can improve the compressive strength of concrete at early and 28 days.Incorporation of fly ash can reduce the thickness of the interfacial transition zone from 70 μm to 50 μm,but the microhardness of the interfacial transition zone is reduced.The incorporation of silica fume can reduce the thickness of the interfacial transition zone from 70 μm to 40 μm.The microhardness of the interfacial transition zone after the incorporation of slag with a specific surface area of 400m2/kg does not decrease.When the content does not exceed 30%,the thickness of the interfacial t ransition zone is 40μm,and when the content is 40%,the thickness is 50μm,50%.The dosage is 60 μm.After incorporating slag having a specific surface area of 1000 m2/kg,the thickness of the interfacial transition zone becomes 40 μm.The incorporation of fly ash can not reduce the total porosity of the cement,but it can refine the pore size of the cement,increase the content of its non-hazardous pores,and reduce the content of harmful and harmful holes.The incorporation of silica fume and slag can reduce the total porosity of the cement stone,and at the same time reduce the content of harmful and harmful holes in the cement stone,increase the content of non-hazardous pores,and refine the pore size of the cement stone.The slag has better effect on the pore structure of the cement stone than the fly ash,and the greater the fineness,the more obvious the effect is...