负温下磷酸镁水泥混凝土的力学性能与抗冻性能

Mechanical properties and frost resistance of magnesium phosphate cement concrete under negative temperature

研究了磷酸镁水泥(MPC)混凝土在20℃、-10℃、-15℃、-20℃养护环境下的力学性能和抗冻性能,为MPC混凝土应用于寒区旱区的抢修工程提供科学依据。MPC混凝土力学性能按照国标GB/T 50081-2002进行试验,抗冻性能按照GB/T 50082-2009进行试验。结果表明:20℃养护条件下,MPC混凝土的28 d抗压强度达到65. 3 MPa,抗折强度达到6. 8 MPa;-10℃养护条件下,28 d抗压强度达到59. 7 MPa,抗折强度达到7. 2 MPa; 300次快速冻融循环后,-10℃养护条件下MPC混凝土质量损失率为3. 5%,相对动弹性模量为83. 5%,抗冻性能优于20℃养护条件下的MPC混凝土。-10℃养护条件下M PC混凝土力学性能和抗冻性能优异,可用于寒区旱区的抢修工程。

In this paper, the mechanical properties and frost resistance of magnesium phosphate cement (MPC) concrete under 20℃, -10℃, -15℃ and -20℃ has studied, in order to provide scientific basis for MPC concrete using in emergency repair engineering in cold and arid environment. The experimental method of MPC concrete mechanical properties was based on GB/T 50081-2002, and the experimental method of MPC concrete frost resistance was based on GB/T 50082-2009. The experiment results showed that under curing condition of 20℃, 28-d compressive strength of MPC concrete is 65.3 MPa and flexural strength is 6.8 MPa. Under curing condition of -10℃, 28-d compressive strength of MPC concrete is 59.7 MPa and flexural strength is 7.2 MPa. The mass loss ratio of MPC concrete is 3.5% and the relative dynamic elastic modulus of MPC concrete is 83.5% under curing condition of -10℃ after 300 fast freeze-thaw cycles. The MPC concrete frost resistance under curing condition of -10℃ is better than that under curing condition of 20℃. In conclusion, the mechanical properties and frost resistance of MPC concrete are excellent under curing condition of -10℃, which could be used in emergency repair engineering in cold and arid environment.