The Influence of Metakaolin and Polypropylene Fiber Concrete on Mechanics Properties and Microstructure Combined Action under Multi-Salt Soaking and Freeze–Thaw

The wide distribution of alpine saline areas in China is faced with two major problems, which are salt intrusion and freeze–thaw. In total, 216 specimens were prepared 6 kinds concrete mix proportions this paper. effects the single compound incorporation metakaolin (MK) polypropylene fiber (PPF) different amounts on mechanical properties microstructure investigated under dual action multi-salt (NaCl, MgCl2, Na2SO4, NaHCO3) soaking Potable water freeze–thaw adopted as control group. Changes appearance morphology, mass loss, relative dynamic elastic modulus, compressive strength tested, was analyzed by scanning electron microscopy (SEM). results showed that an admixture both MK PPF potable cycle test can improve frost resistance concrete. effectively However, failed to during optimally improved 10% 0.6 kg/m3 PPF. Its shows inhibit crack propagation reduce deterioration