Research On Frost-damaged Concrete Strengthened With Polypropylene Fiber Reinforced Fine Aggregate Concrete

Large areas of low temperature and snow disaster occurred in China Southern in 2008, which led the freeze-thaw resistance property of concrete and other building materials , as well as the repair of building become the attention and research hot spots. On the basis of experimental research on bonding property of fresh fiber reinforced fine aggregate concrete with frost-damaged concrete. Experimental research on frost-damaged concrete strengthened with polypropylene fiber reinforced fine aggregate concrete was made in this paper.The main contents of research are as follows:1. The freeze-thaw resistance property of polypropylene fiber reinforced fine aggregate concrete was explored. The main factors were researched, such as the content of polypropylene fiber, the strength of concrete and adhesive agent. The test results indicated that the use of polypropylene fiber in new concrete could improve the freeze-thaw resistance property of fine aggregate concrete, and reduce the effect of freeze-thaw cycles on the basic mechanical properties of fine aggregate concrete. In some range of polypropylene fiber content, with the increase of fiber content, the freeze-thaw resistance property of fine aggregate increased continuously.2. The bonding property of polypropylene fiber reinforced fine aggregate concrete with frost-damaged concrete was tested. The main factors were researched, such as content of polypropylene fiber, adhesive agent and role of freeze-thaw cycles. The test results indicated that the bongding capacity of polypropylene fiber reinforced fine aggregate concrete with frost-damaged concrete was damaged seriously by the role of freeze-thaw cycles, the use of polypropylene fiber in fresh concrete could improve the bonding strength of fresh fiber reinforced concrete with frost-damaged concrete obviously and the freeze-thaw resistance property of bonding interface. As well as, adhesive agent had some influnence on the bongding strength of polypropylene fiber reinforced fine aggregate concrete with frost-damaged concrete, and the effect of concrete interface agent was better than cement paste agent's.3. The holistic property of frost-damaged concrete strengthened by polypropylene fiber reinforced fine aggregate concrete was studied. The main factors were analyzed. The test results indicated that the compressive and tensile splitting strength recovered successfully. As the number of freeze-thaw cycles increased, the compressive and tensile splitting strength declined rapidly. As well as, the use of polypropylene fiber in fresh concrete could improve the freeze-thaw resistance property of repaired concrete.4. The influnces of polypropylene fiber and air-entraining agent on the freeze-thaw resistance property of fine aggregate concrete were discussed. The main factors were researched, such as the content of polypropylene fiber and the content of air-entraining agent. The experimental results indicated that in some range of fiber content and aie-entraining agent, polypropylene fiber and air-entraining agent could improve the freeze-thaw resistance property of fine aggregate concrete obviously, and reduc the effect of freeze-thaw cycles on the basic mechanical properties of fine aggregate concrete.