Study on Mechanical Properties of Low Calcium Bentonite Recycled Aggregate Concrete
In order to improve the performance of recycled aggregate concrete compared to natural aggregate concrete,low calcium bentonite with a mass substitution rate of 0,5%,10%,15%,and 20%was used to replace ordinary portland cement to prepare specimens.The workability,fresh mix density,air content,compressive strength,and splitting tensile strength tests were conducted.The experimental results show that the workability of recycled aggregate concrete is higher than that of natural aggregate concrete.As the amount of bentonite increases,the workability of both natural aggregate concrete and recycled aggregate concrete decreases.When other conditions are the same,the air content of recycled aggregate concrete is relatively higher than that of natural aggregate concrete.When high-efficiency water reducing agents are not used,the air content of natural aggregate concrete and recycled aggregate concrete increases with the increase of bentonite content.When using high-efficiency water reducing agents to achieve the target slump,compared with the corresponding control group,the air content of natural aggregate concrete and recycled aggregate concrete decreases with the increase of bentonite content.Under the same conditions,the density of recycled aggregate concrete is lower than that of natural aggregate concrete.When no high-efficiency water reducing agent is added,adding bentonite will reduce the density of fresh recycled aggregate concrete and natural aggregate concrete.When adding a high-efficiency water reducing agent with the target slump dosage,the addition of bentonite will increase the density of fresh recycled aggregate concrete and natural aggregate concrete.The addition of bentonite significantly improves the later strength of recycled aggregate concrete aggregates.When the replacement rate of bentonite is 15％,the tensile and compressive strength of recycled aggregate concrete and natural aggregate concrete increase the most.
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