III级原状粉煤灰混凝土的强度特性研究

摘要

In order to make use of grade III fly ash effectively and fully,to C30 concrete that used commonly as the research object,with the grade III fly ash as the basis,sand coarse aggregate ratio,pumping agent dosage,equivalent efficiency of grade III fly ash etc.as the factors,the single factor test and the scheme L9(34) orthogonal test were designed.Then,the action law of the original grade III fly ash influence on the workability and compressive strength of concrete was contrasted and studied ,the applied possibilities and reasonable dosage of grade III fly ash in C30 concrete was explored.The results show that the compressive strength of concrete mixed grade III fly ash decreases with the increase of the sand coarse aggregate ratio and increases at first then decreases with the increase of equivalent efficiency and the quantity of pumping agent,and the optimal equivalent efficiency is 100 percent.Simultaneously,the equivalent efficiency and sand ratio are the important factors for the compressive strength of concrete that mixed the grade III fly ash.The grade III fly ash can be compounded in the C30 concrete,and the reasonable equivalent efficiency is about 80.0 percent.Conclusions have the theoretical significance and practical value to the resource use of the poor fly ash.%为有效和充分利用III级粉煤灰，以常用强度等级C30混凝土为研究对象，I级粉煤灰的掺量为基准，砂率、泵送剂掺量、III级粉煤灰的等效率等为因素，设计单因素试验和正交试验L9（34）方案，对比研究III级原状粉煤灰对混凝土工作性和强度的作用规律，探索III级粉煤灰在C30混凝土中应用的可能性及合理掺量。研究表明：III级粉煤灰混凝土的强度随砂率的增大而减小，随等效率和泵送剂掺量的增大，呈现先增大后减小的趋势，最优等效率为100.0%；等效率和砂率是影响III级粉煤灰混凝土强度的重要因素；可用III级粉煤灰配制强度等级C30的混凝土，合理等效率约为80.0%。研究结论对劣质粉煤灰的资源化利用有理论意义和实用价值。