Research On Performance Of Manufactured Sand Cement Concrete Modified With Polymer

The natural river sand is a kind of local resource which is difficult to regenerate.In order to save natural sand,the manufactured sand is generally used for cement concrete pavement in the project.Ordinary cement concrete has the shortcoming of brittleness and poor durability,after the manufactured sand to replace natural sand,the abrasion performance of cement concrete is also decreased definitely,which limits the application of sand concrete in highway pavement.Polymer modified cement concrete(PCC)has good toughness,deformation performance and durability.On the basis of ensuring good economy,the low content of polymer is used for improving the mechanical property and abrasion performance of cement concrete of manufactured sand.On the basis of literature research,polyacrylic acid ester emulsion and carboxylic styrene butadiene latex which are selected with polymer cement ratio of 1%,3% and 5% in this paper.Overall calculation method,the filling theory of liquid cement and surplus coefficient are used for mixture ratio design.The results of the slump test of fresh cement concrete,the cubic compressive strength test,the flexural tensile strength test,the abrasion performance test of cement concrete,the oretical analysis,XRD and SEM show that the flowability,cohesiveness and water retention of the fresh cement concrete are good;the strength of the manufactured sand cement concrete modified with polymer is lower than that of ordinary cement concrete,but still meets the requirements of pavement concrete;with the increase of polymer cement ratio,for the manufactured sand cement concrete modified with polymer,the flexural tensile strength increased,bend-press ratio increased,wear per unit area decreased;the content of calcium hydroxide and ettringite after hydration reduced with the increase of polymer cement ratio,and the content of dicalcium silicate increased with the increase of polymer cement ratio;With the increase of polymeric content,the voids and microcracks in cement concrete are obviously reduced,the polymeric membranes which are intertwined with cement hydration products,the whole system is gradually forming continuous dense structure.The results in this paper show that: The polymer improved the workability of the fresh cement concrete,the brittleness of cement concrete is decreased,the abrasion performance of cement concrete is improved;the active radical group in the polymer has the ability of reaction with the calcium ion in the cement concrete;after blending of polymer,the internal structure of cement concrete is better than before,the dense of cement concrete is increased,the cohesive property between cement concrete and aggregate increased.Generally,the polymer can improve the mechanical properties and abrasion performance of the cement concrete of manufactured sand.The best amount of additive of polyacrylate and carboxylic styrene butadiene latex in the range of low content(?5%)is respectively 3% and 5%.