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传统的自密实混凝土(SCC)集料含量偏低、胶凝材料用量较高,同时制备SCC的细集料一般采用的是河砂,但是河砂作为短期内不可再生资源,且地域性很强。这些因素使得现在SCC造价高昂,而且会造成较大的资源浪费。因此本文用机制砂代替河砂作为细集料,用关键因素法设计配比,通过集料级配优化来提高粗集料的含量,减少胶凝材料的用量,实现生态性。同时研究堆叠率(PR)、砂体积率(VSR)、粗集料级配等因素对自密实混凝土工作性的影响。实验表明关键因素法能成功设计出堆叠率为0.6,砂浆含砂率为0.42的机制砂生态自密实混凝土,胶凝材料用量544kg/m3,水泥用量381kg/m3,扩展度达到655mm,T500测试时间为4.6s,间隙通过性10mm,H2/H1为0.8,减少胶凝材料的同时符合SCC工作性要求。
The traditional self-compacting concrete (SCC) aggregate content is low, the amount of cementitious material is high, while the preparation of SCC fine aggregate generally used river sand, river sand as a short-term non-renewable resources, and very strong . These factors make SCC expensive now, but also cause greater waste of resources. In this paper, we use sand instead of river sand as the fine aggregate, and design the ratio by the key factor method. Through the optimization of the aggregate gradation, the content of the coarse aggregate is increased, the amount of the cementitious material is reduced, and the ecology is realized. At the same time, the effects of factors such as stacking rate (PR), sand volume fraction (VSR) and coarse aggregate gradation on the workability of self-compacting concrete were studied. Experiments show that the key factor method can successfully design a mechanism sand ecological self-compacting concrete with a stacking rate of 0.6 and a mortar sand content of 0.42. The dosage of cementitious material is 544kg / m3, the cement dosage is 381kg / m3, the expansion degree is 655mm, T500 test time 4.6s, the gap through the 10mm, H2 / H1 is 0.8, reducing the cementitious material at the same time meet the SCC work requirements.