Study on frost resistance durability of lightweight aggregate concrete improved by fiber

摘要

Pumice, polypropylene fiber, steel fiber and fly ash were used to compound fiber reinforced lightweight aggregate concrete (LWAC). The effect of fibers on frost resistance durability of LWAC is studied, which including freezing-thawing in 5% Na_2SO_4 solution and in water. The test results show that the strength loss of LWAC is reduced with the increase in fiber fraction, but the impact of mass loss is not obvious by mixing fiber. LWAC freezing-thawing deterioration is even more serious in salt solution than in water. SEM photo show that polypropylene fiber has more stronger cementing bond with paste than steel fiber, the mass loss and strength loss are decreased significantly. By introduction silica fume can improve Interfacial Transition Zone (ITZ) and the frost resistance of fibers reinforcement LWAC dramatically.