Experimental Research On Recycled Concrete One-way Slab At High Temperature

In recent years, the construction industry has been developing rapidly in our country. With the foundation of the new buildings, a large number of old buildings were demolished, which generated a lot of construction waste. Construction waste recycling is an effective method to solve the problems. Environmentally friendly recycled concrete has been more and more paying attention and recognition for a material of great significance to the sustainable development of the construction industry.At present, the research of recycled concrete has made some progress, but less research on the force and fire resistance of component or structure. In response to this situation, the author designed eight different proportion of recycled aggregate for C40 concrete one-way slabs, which four took bearing capacity tests conducted at ambient temperature and the other four were fire resistance test at a high temperature. The paper include the study of recycled concrete compressive strength of different aggregate replacement rate at ambient temperature or after high temperature, as well as the development of cracks, deflection, ultimate load, the fire resistance at high temperature.Research indicated that at ambient temperature, the greater the rate of recycled aggregate, the smaller the compressive strength. Both the compressive strength of normal concrete and recycled aggregate concrete is lower after the high temperature, but compressive strength of full recycled aggregate concrete declined smallest. At ambient temperature, the rate of recycled aggregate is little effect on concrete slab bearing capacity. Meanwhile, the crack of ordinary concrete slab is very little when the failure occurred, and the crack uniformity is not as good as the full recycled aggregate concrete slab. All the recycled aggregate concrete slabs in different rates can reach 1.5 hours fire resistance requirements. The fire resistance of one-way slab was greatly impacted by the rate of recycled coarse aggregate replacement at high temperatures. The more recycled aggregates, the slower the internal temperature, the smaller the deflection and the better the fire resistant.The purpose of this research, the first is to provide a reference for the force and fire resistant design of recycled concrete one-way slab, the second is to supply the test data for the recycled concrete structure reinforcement after fire. After all, it is to make best effort to promote the recycled concrete technology. We hope follow researches to do more systematic study of recycled concrete technology.