Influence of Polypropylene Fiber on the Properties of Bridge Deck Pavement Lightweight Aggregate Concrete

The influence of polypropylene fiber on workability and strength of bridge deck pavement lightweight aggregate concrete is investigated,and the change of cracking time,cracking areas and cracking numbers are studied when lightweight aggregate is pre-wetted and polypropylene fiber and steel fiber are added in it.The results indicate that the fluidity of lightweight aggregate concrete decreases with the adding of polypropylene fiber,the initial slump and slump flow are just 69% and 64% of that without polypropylene fiber when the mixing amount of polypropylene fiber is 1.2 kg/m³.The segregation degree of concrete was small when the mixing amount of polypropylene fiber is 0.6 kg/m³.And there is an optimum mixed amount of polypropylene fiber,the compressive strength for 28 d changes little but the flexural strength for 28 d increases to some extent at 0.6 kg/m³ of polypropylene fiber.In addition,cracking resistance test indicates that it can stop and delay the crack caused by early-age plastic shrinkage by pre-wetting lightweight aggregate and adding fiber,and enhance early cracking resistance.