再生骨料级配对再生保温混凝土抗压强度的影响

Effects of gradation on compression strength of recycled aggregate thermal insulation concrete

为研究再生骨料级配对再生保温混凝土抗压强度及其离散性的影响规律,对四种不同再生骨料级配配制的混凝土进行抗压强度试验,并计算抗压强度标准差。以骨料级配为变量,分析了再生保温混凝土抗压强度的变化趋势。研究表明：通过人工调配可提高骨料的物理性质以及优化骨料级配。级配调整后不仅可以提高混凝土抗压强度,也可有效降低抗压强度的离散性,标准差在1~3 MPa范围内。当分别增加大粒径（9.5~19 mm）、小粒径（4.75~9.5 mm）再生粗骨料时,虽依照现行普通混凝土规范[《混凝土泵送施工技术规程》（JGJ/T10-2011）]表现为级配不良,但出现了强度分别提高27.3%和14.1%的现象。同一级配下再生保温混凝土抗压强度呈正态分布,级配调整后,再生保温混凝土抗压强度正态分布曲线均值增加。再生骨料级配调整,可为再生保温混凝土的推广应用提供一定的技术手段。

To get a better understanding on the compressive strength and discreteness of recycled aggregate thermal insulation concrete（ RATIC） affected by recycled coarse aggregate（ RCA） gradation,an experiment has been carried out on concrete of four different recycled aggregate gradations.The relationship between compressive strength and recycled aggregate gradation is analyzed,and the standard deviation of compressive strength is calculated. The research shows that the gradation of recycled coarse aggregate produced by industry is poor,and the physical properties and gradation of the aggregate can be improved by artificial mixing. The gradation adjustment can not only enhance the compressive strength of the RATIC,but also decrease the separation of the compressive strength,and the standard deviation falls in a range of 1 ~ 3 MPa. After increasing the ratio of medium size（ 9. 5 ~ 19 mm） and small size（ 4. 75 ~ 9. 5 mm） of RCA,the compressive strength of the RATICwere increased by 27. 3% and 14% 1%,respectively,although the particle gradation was poor according to the Technical Specification for Construction of Concrete Pumping（ JGJ / T10-2011）.The compressive strengths of RATIC are normal distribution under the same gradation,and the mean compressive strength of RATIC increases after the gradation adjustment. Recycled aggregate gradation adjustment provides a way for the promotion and application of RATIC.