| Recycled coarse aggregate concrete is prepared with recycled coarse aggregate instead of natural coarse aggregate with a particle size of 5~40 mm, while the recycled coarse aggregate is obtained from waste concrete after crushing and sieving. Not only nature aggregate is saved, but also environmental pollution from waste concrete is eased due to the research and application of recycled concrete, and it has important meaning to the sustainable development and environmental protection. In this paper, nature aggregate was replaced with recycled coarse aggregate with 0, 50% and 100% three levels, and calcium sulfate whisker was added to the concrete with 0, 0.5, 1.0, 1.5, 5.0, 10, 15 kg/m3 seven levels.The influence of recycled coarse aggregate replacement and calcium sulfate whisker addition amount on the basic properties of concrete was studied.The main research work and achievements are:(1) The working performance of calcium sulfate whisker recycled concrete was studied mainly on cement setting time and fresh concrete slump. The influence rules of cement setting time with different calcium sulfate whisker addition amount and the influence rules of fresh concrete slump with different recycled coarse aggregate replacement and different calcium sulfate whisker addition amount were obtained.(2) The mechanical properties of calcium sulfate whisker recycled concrete was studied mainly on cube compressive strength in different age, splitting tensile strength in different age, axial compressive strength and modulus of elasticity. Early cracking resistance of concrete was evaluated by splitting and compressive ratio. The influence rules of mechanical properties of concrete with different recycled coarse aggregate replacement and the optimal addition amount of calcium sulfate whisker to improve mechanical properties were obtained.(3) The basic durability of calcium sulfate whisker recycled concrete was studied mainly on impermeability and water resistance. The influence rules of basic durability of concrete with different recycled coarse aggregate replacement and the optimal addition amount of calcium sulfate whisker to improve basic durability were obtained.Through testing and data analysis, the influence of recycled coarse aggregate replacement and calcium sulfate whisker addition amount on the properties of concrete was studied systematically in this paper. The results of this paper can provide a theoretical and experimental basis for the application of recycled concrete. |
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