Experimental Study On Impact Resistance Of Straw Fiber Reinforced Cementitious Composites

Traditional cement-based materials are low-cost,widely used and widely used building materials.However,the disadvantages of high brittleness,poor crack resistance,low tensile strength and poor impact load resistance limit its far-reaching construction.Development.Studies have shown that the incorporation of fibers can effectively improve the defects of cement-based materials,and with the further demand of new building materials,plant fiber cement-based composite materials are also becoming more and more popular.Combining plant straw fiber with cement-based materials,on the one hand,it solves the problem of waste utilization of crop straws.On the one hand,it obtains cement-based composite materials with light weight,thermal insulation and sound absorption characteristics,which not only improves the comprehensive utilization rate of straw.It also provides a broader development prospect for plant fiber cement-based composite materials.With the addition of straw fiber granules,the water consumption of the standard consistency of the composite increases,and increases linearly with the increase of the dosage.When the amount of straw fiber granules is 3%-8%,the standard consistency water consumption is cement.The pulp is 1.26-1.7 times;when the amount of straw fiber particles is increased,the bulk density,flexural strength,compressive strength and elastic modulus of the cement-based composite material are reduced to different extents.Compared with the cement paste test block,when the amount of straw fiber granules is 3%-8%,the bulk density of the composite decreases by 13.8%-25.4%,the flexural strength decreases by18.99%-31.65%,and the compressive strength decreases by 18.42%-38.9%.The drop impact test of composite materials,with the increase of the amount of straw fiber particles,the initial cracking,final cracking times,impact energy and impact toughness of the composites increased to varying degrees,and increased with the increase of the amount of rice.After the ascending and decreasing trend,when the amount of straw fiber particles is5%,the impact resistance of the composite material increases,the absorbed energy value increases,and the impact resistance performance is most significantly improved.When the dosage is 6%,the composite material resistance is increased.The impact performance is reduced,and 5% is the optimum dosage.As the amount of straw fiber particles increases,the brittleness of the composite material is significantly improved,the crack width is reduced but the number is increased,the pit depth is increased,and the pre-crack contact force is generated.There is no obvious change in the peak value,the contact time between the punch and the test block increases,and the damage time of the test block is prolonged.The energy of the composite materials with different dosages is basically the same with time,and the energy is roughly divided into rapid rise to maximum value and punch recovery.When the energy is reduced and the punch is detached,the energy tends to be stable in three stages;under low-speed impact,the impact speed increases,the energy generated by the impact increases,and the peak contact force increases.Impact generated pit depth increases,to increase the area of ??damage,increase in the number of cracks in the matrix,the punch in contact with the composite plate to extend from the time,the maximum value of the composite plate deformation increases.