Research On Properties Of RPC Reinforced With Fibers

At present,the common ordinary concrete structures have a series of drawbacks of the high weight,the big size,brittleness problem and so on around the world.Those not only greatly reduce the bearing capacity and the space utilization rate,but cause the waste of resources,and the environmental pollution is also very serious.Therefore,it need us pay more attention to develop the new type structures with light weight,small space occupancy,strong bearing capacity,and in accordance with the concept of energy conservation and environmental protection and others.The emergence of reactive powder concrete can realize this kind of concrete structure in theory.However,the study of material performance of RPC is not perfect enough.Therefore,we must speed up the space of studying and optimizing the performance of RPC.In this paper,through to improve the traditional RPC material and incorporate fibers in the RPC,respectively to test the fluidity properties,mechanical properties and toughness properties of RPC by incorporating silica fume,slag powder,fibers,high efficiency water reducing agent,defoaming agent and so on,to study the impact of the main components on the fluidity properties and mechanical properties of RPC.According to the ASTM C1018 toughness index method,the toughness improving effects of the different volume dosage of steel fiber,PP fiber and a mixture of both for RPC also are researched.Develop the new fiber RPC with good fluidity properties,good mechanical properties and good toughness properties.The results show that:(1)The impact of W/B on the fluidity properties and mechanical properties of RPC is very obvious.The homogeneity and fluidity of cement of RPC can reach the optimal,and has excellent mechanical properties,while the W/B has been controlled between 0.18~0.20 in the test.(2)The mineral admixture(Silica fume and slag powder)can improve the compactness of RPC,and produce a certain effect on the fluidity properties and mechanical properties.(3)The steel fibers can obviously enhance the effect of RPC,especially for the folding strengthe with improving double.The test shows that the micro steel fiber is better than the super micro steel fiber in improving the mechanical properties.Due to the limitation of the physical properties of PP fiber,it’s easy to cause more internal defects in RPC,and produce a negative impact.Therefore,the PP fiber is not a good choice to add to this concrete.(4)The efficient polycarboxylate superplasticizer plays a key role in improving the fluidity properties of RPC.Through to add to 2.0%~2.5% of polycarboxylate superplasticizer in the slurry of RPC,and keep W/B with 0.2 or so,we can control the fluidity diameter more than 30 cm and still keep the excellent mechanical properties by allocating other components.(5)The steel fibers can obviously improve the toughness properties of RPC.Text results show that the volume dosage of 2.0%~2.5% single micro steel fibers is more reasonable for improving the flexural toughness and peak load;when the volume dosage of 1.5% micro steel fibers mixed with the volume dosage of 0.15% pp fibers,the effect on the toughness was more reasonable;Single pp fibers was not obvious on improving flexural toughness of RPC and almost produced negative effect for peak load.