Study On The Characteristics Of Straw-based Concrete

Due to the advancement of the process of urbanization, lots of different functions and different types of concrete are required in urban construction. With the increasing types of concrete, new materials and new technologies are required. In order to economically improve the performance of concrete, biomass fiber, or the mineral with hydraulic activity has begun to be used for concrete admixtures. It is learned that rice straw or others fiber-rich can play the role of reinforced in concrete to some extent. As well, rice and other straw contain free silica with hydraulic activity. However, so far, the study at home and abroad are limited to a very small portion of the crop residue such as wheat straw and rice husk. It is uncommon research about rape and other straw.Based on the status quo above, rape straw as the research object, the performance of straw-based concrete is intensively studied. In this paper, the rape straw crushed is added to the concrete. The factors affecting the hydraulic activity of rape straw ash are experimental studied, in order to find out the optimum excitation condition of silica hydraulic activity. the rape straw ash gotten in the optimum condition is added to the concrete. Then, the indexes of concrete performance are respectively measured and analyzed. The main conclusions are as follows:(1) Under the same conditions of mix proportion, with the increase in the amount of rape straw, apparent density and compressive strength of the concrete decrease; but when straw length is longer than2.0cm, The decrease of compressive strength of the concrete has slowed down, and the concrete at the ultimate bearing state shows good plasticity.(2) Compared with the non-wash, wash can increase the relative content of the SiO2by60%,and reduce the alkali metal and volatile substances of the straw by about50%, and effectively improve the ash melting point, reduce slagging rate and. That is to say,the optimal experimental condition to activate potential hydraulicity of SiO2is: Rape straw after washing, calcined5hours at500℃.(3) The optimum quality of the straw ash added to concrete is about20%of cement. When the quality of straw ash is20%of cement, and the Water-Cement ratio is 0.5, the performance of concrete is the best.(4) The method of add crushed straw in concrete is suitable for the non-main structures which less demanding on the concrete strength but its toughness required; The method of add straw ash in concrete is suitable for the main structures of rural building. The use of local materials comes ture.