| Rammed earth building is not only warm in winter and cool in summer,comfortable living,with low cost of materials,but also the construction process of energy saving and environmental protection,at the same time has degradable,recyclable,with excellent ecological environmental benefits.However,due to the poor mechanical properties of rammed earth materials,coupled with the traditional rammed earth residential buildings are mainly farmers self-built,lack of professional support,resulting in poor seismic performance,in successive earthquakes damage is very serious.Based on the experimental study of rammed earth materials,this paper optimizes and improves the mechanical properties of rammed earth materials,on the other hand,emphatically analyzes the main factors affecting the compressive strength of rammed earth materials,and on this basis,puts forward the test methods which are more in line with the characteristics of rammed earth materials.The main research contents are as follows:(1)Using cube specimens,this paper makes a preliminary analysis of the main factors affecting the compressive strength of rammed earth,and summarizes 3 main influencing factors,namely cube size,soil and gravel ratio and additive type and ratio,and uses single factor test,respectively,to study the 3 influencing factors in turn.(2)According to the modern rammed earth construction technology,to soil,sand,stone as the basic materials,through the production of 4 groups of a total of 24 different cube sizes(150mm×150mm×150mm,200mm×200mm×200mm,250mm×250mm×250mm,300mm×300mm×300mm)of rammed earth cube specimens,a single-axis compressive strength test was carried out to study the compression failure process and fracture distribution patterns,and the effects of different cube sizes on the compressive properties of the rammed earth cube specimens were compared and analyzed.This paper analyzes the dispersion of compressive strength of rammed earth cube specimens of different sizes,finds out the appropriate size of rammed earth cube,and paves the groundwork for subsequent tests.(3)based on the above research results,the soil,sand and stone as the basic materials,through the production of 10 groups of a total of 60 different soil and gravel ratio(quality ratio of 5:4:1,5:3:2,5:1:4,5:5:0,5:0:5,6:2:2,6:1:3,6:3:1,4:3:3,3:4:3)of rammed earth cube specimens,the compressive strength test of the cube was carried out,the compression failure process and fracture distribution morphology were studied,the effects of different soil and gravel ratios on the compressive properties of the rammed earth cube specimens were compared and analyzed,and the suitable ratio of rammed earth cube soil and gravel was found,and the subsequent tests were carried out.(4)Taking soil,sand and stone as the basic materials,through the production of 12 groups of 72 different additive types and ratios(cement,cooked lime,XJP soil curing agent,fiber materials,water glass)of the rammed earth cube specimen,the cube compressive strength test was carried out to study its compression failure process and damage distribution,The effects of different additive types and ratios on the compressive properties of rammed earth cube specimens were compared and analyzed.The experimental results show that the rammed earth specimen should adopt 200mmx200mmx200 mm cube specimen,the ratio of 3 basic materials soil,sand and stone should be selected 4:3:3(quality ratio),and the compressive strength of the modified rammed earth cube specimen can reach 3.0~6.0mpa,Is the 2~3 times of the compressive strength of the rammed earth specimen,and the ductility is improved,so the rammed earth material still has a good application prospect. |
