全再生混凝土力学性能及导热性能研究

Study on mechanics and thermal conductivity of fully recycled concrete

采用再生粗骨料(RCA)、再生细骨料(RFA)及再生微粉(RCP)制备全再生混凝土,通过正交试验研究了水胶比、RCA取代率、RFA取代率、RCP取代率和AOS引气剂掺量对全再生混凝土性能的影响。结果表明:AOS引气剂掺量对全再生混凝土抗压强度、抗折强度、折压比及比热容的影响最大,强度总体上随AOS引气剂掺量的增加先降低后提高。RCA取代率对导热系数影响最大,RCA取代率为50%时,导热系数最小。最优配合比为:水胶比0.43、RCA、RFA、RCP取代率分别为75%、50%、15%、不掺AOS引气剂,制得的全再生混凝土抗压、抗折强度分别为45.8、4.6 MPa、导热系数为0.9844 W/(m·K)、比热容为0.8807 MJ/(m^(3)·K)。

Fully recycled concrete was prepared by using recycled coarse aggregate(RCA),recycled fine aggregate(RFA)and recycled micro-powder(RCP).The effects of water-cement ratio,RCA replacement ratio,RFA replacement ratio,RCP ratio and AOS air entraining agent content on performance of fully recycled concrete were studied through orthogonal tests.The results show that the content of AOS air entraining agent has the greatest influence on the compressive strength,flexural strength,flexural strength ratio and specific heat capacity of fully recycled concrete,and the strength decreases first and then increases with the increase of the content of AOS air entraining agent.The most influential factor on the thermal conductivity is the replacement rate of RCA.When the replacement rate of RCA is 50%,the thermal conductivity is the lowest.The optimum mix ratio is:water cement ratio is 0.43,RCA replacement rate is 75%,RFA replacement rate is 50%,RCP replacement rate is 15%,and AOS air entraining agent content is 0.In this case,the compressive strength is 45.8 MPa,the flexural strength is 4.6 MPa,the thermal conductivity is 0.9844 W/(m·K),and the specific heat capacity is 0.8807 MJ/(m^(3)·K).