Experimental Study on Durability of High Titanium Heavy Slag Recycled Concrete

Replacing coarse and fine aggregates of high-titanium heavy slag with 50%,75%,and 100% replacement rates of coarse and fine aggregates of high-titanium heavy slag to prepare high-titanium heavy-slag recycled concrete with strength classes C20,C25,C30 was carried out,and the 28-day strength was measured.The durability of the samples was studied by resistance to chloride ion penetration test,rapid freeze-thaw test,and resistance to sulfate wet and dry cycle erosion test.The test results show that the measured strength of the recycled concrete decreases with increase of the replacement rate of the recycled aggregate,and the measured strength of each strength grade concrete can reach the design strength,but the strength margin is small.The D_RCM value of the recycled concrete decreases with increase of the replacement rate and strength of the aggregate.The minimum and maximum D_RCM values are 2.3×10^-12 m²/s and 3.3×10^-12 m²/s,respectively.The frost resistance of recycled concrete increases with gradual increase of the replacement rate of recycled bone and the strength grade,but only the C25 recycled concrete with 75% and 100% recycled aggregate and the C30 recycled concrete with 100% replacement reach the freeze-thaw rating of 100 freeze-thaw cycles.The effect of 30 sulfate dry-wet cycle erosions on the strength of recycled concrete is small.At the same strength level,the resistance to sulfate erosion of recycled concrete decreases with the increase of the replacement rate of recycled aggregate.The smaller the strength level,the smaller the decrease amplitude.