Research On The Physico-mechanical Properties And Durability Of Crumb Rubber-modified Concrete

Take advantage of waste tire crumb rubber for modifying cement concrete is a multipurpose utilization of waste rubber.It will play a significant role in utilization resources,environmental protection and modified materials.In this paper,the physico-mechanical properties and durability of rubber modified mortars(RMM) and rubber modified concretes(RMC)are investigated systematically.The effect of rubber content and rubber surface modifying on properties of RMC are discussed. The physico-mechanical properties and durability of dry concrete added with crumb rubber are investigated too.And its properties have been compared with RMC's.Properties of flash concrete and mortar testing indicate that the fluidity of mortars are improved,air content of concrete is increased as the addition of crumb rubber.The addition of crumb rubber can increase the quantity of pressure bleeding (V₁₄₀),decrease the pressure bleeding rate(B_V)and improve the workability of flash RMC.Mechanical property testing indicates that the compressive and flexural strengths of mortars and concretes are decreased,but the dynamic ductility is obviously increased.When the RMC is being done strengths test,it wouldn't be quickly broken like the ordinary concrete.And it can still keep in good shape that shows powerful crack resistance.Through surface modification treatment,the modified crumb rubber can improve compressive strength of cement paste obviously.And the modifier titanate coupling agent has the best effect.The treated crumb rubber has little effect in improving strengths of mortar and compressive strength of concrete,but it can bring a striking effect in improving flexural strength of RMC.Durability research shows that the crumb rubber can reduce the dry shrinkage, improve frost resistance property and abrasion resistance of RMC.But the addition of crumb rubber has negative influence on the carbonation resistance property and impermeability of RMC.The study of dry concrete added with crumb rubber indicates that,comparing with ordinary concrete,the crumb rubber has less negative influence on dry concrete. And the dry-shrinkage value of dry concrete is much lower than ordinary concrete.It can be drawn the conclusion that dry concrete is more suitable for adding crumb rubber than ordinary concrete.