混和材(3)／副産物利用・再生材料(1)

[V-24] Fundamental properties of fine aggregate recovered from returned concrete at multiple factories

〇Yuma Miyamoto¹, Ken Ohkawa¹, Tetsuro Kasai² (1.SANWASEKISAN , 2.TOKAI University)

Keywords:Return concrete, Multiple factories, Collected fine aggregate, Sodium gluconate method, Condensation, Compressive strength

In March 2014, JISA5308 was revised and announced, and the handling of recovered aggregate was stipulated. The use of recovered aggregate is permitted only for ready-mixed concrete shipped at its own factory. However, according to the 2017 Building Standard Equipment Promotion Project Report Meeting, there is a report that 0.65% of the factories that have standardized concrete using recovered aggregates have not been widely used. On the other hand, it is considered that it is indispensable to collect return concrete from multiple ready-mixed concrete factories from the viewpoint of efficient return concrete treatment at ready-mixed concrete plants because the working population is inevitable.