Study On Full Non-Autoclaved Preparation Technology And Performance Of PHC Pipe Pile Concrete

At present,PHC pipe pile is mainly used in the first atmospheric pressure steaming(80～90℃)after high temperature and high pressure steaming(180～190℃,1MPa)secondary curing process.The curing process has the characteristics of large investment costs,high energy consumption,environmental pollution,that does not meet the current social development trend of energy saving and emission reduction.This paper carries out a study on full non-autoclaved preparation technology of PHC pipe pile that removes atmospheric pressure steaming and high temperature and high pressure steaming secondary curing process,analyzes the durability,microstructure,energy consumption and benefit of full non-autoclaved PHC pipe pile concrete.The main work and achievements of the paper are as follows:(1)Key factors of full non-autoclaved PHC pipe pile concrete are studied.The results showed that:the special superplasticizer of functional pipe pile is formed by aliphatic modified poly carboxylic acid superplasticizer and superplasticizer of fast dispersion and viscosity reduction which is compounded by the quality ratio of 7:3,its volume is 2.0%of cementitious materials,the amount of cementitious materials is 480kg/m~3,volume of the slag powder is 20%of cementitious materials,sand ratio is 34%,water binder ratio is 0.24,7d compressive strength of PHC pipe pile concrete is96.8MPa,workability is good.(2)The durability of full non-autoclaved PHC pipe pile concrete is studied.The results show that:full non-autoclaved PHC pipe pile concrete is good in resistance to chloride ion permeability,sulfate attack resistance and frost resistance,and its durability is slightly stronger than that of PHC pipe pile prepared by the secondary curing.(3)The microstructures of full non-autoclaved PHC pipe pile concrete are analyzed.The results of SEM show that:compared with the PHC pipe pile concrete prepared by the secondary curing,cement paste structure of full non-autoclaved PHC pipe pile concrete is more complete,the distribution of hydration products is more evenly,the structure surface is more dense.(4)Energy consumption and benefit of full non-autoclaved preparation technology is studied.Full non-autoclaved preparation technology can save energy consumption4.625×10~5 kJ/m~3,save costs 8.8 yuan/m,has good promotion prospect.