Study On Concrete Mix Ratio Of Non-autoclaved PHC Pipe Pile

The quality of prestressed high strength concrete(PHC) pipe pile is reliable, with which construction must be highly mechanized, short time limit and low cost, for transport is convenient and pile connecting is quickly. It’s widely used in the major projects of industrial and civil buildings, docks, municipal engineering and bridges. Usually, PHC pipe pile needs to be autoclaved in the production process. Autoclaving means high energy consumption, environmental pollution, large equipment investment, and contains potential safety risk.This subject is commissioned by a concrete pipe Limited company. The research is about non-autoclaved PHC pipe pile, major on the study of concrete mix ratio of PHC pipe pile, as well as method of improving the pipe pile concrete strength achieve80N/mm2rapidly in the state of normal pressure maintenance.The subject chose the active material such as silica fume, nanometer silicon, chaff ash, powder coal ash, granulated blast furnace slag powder as concrete admixture, improve the early strength of the concrete by adding polycarboxylate superplasticizer and heating maintenance with maintenance box, thus, the cube compressive strength standard values of concrete achieve80N/mm2in a relatively short time. Through multiple groups of mix ratio test can be drawn:with20%S95granulated blast furnace slag powder, water binder ratio0.23, using PII52.5Portland cement, cementitious material consumption is500kg/m3, add1%Nanchang Branch of poly carboxylic acid water reducing agent can make the concrete compressive strength to reach more than80N/mm2in seven days.Using micro silica powder, granulated blast furnace slag powder, powder coal ashcan form a superposition effect of concrete, and achieve the purpose of non-autoclaved. But the micro silica powder is relatively high cost, the plan will increase the production cost.The use of powder coal ash as admixture can improve concrete workability, but due to slow hydration speed of powder coal ash, concrete’s early strength will be reduced.The maximum Influence to the concrete compressive strength is the type of high efficiency water reducing agent, followed by the water cement ratio, then the mineral admixture replacement rate.