Research On The Application Of PC-HB Water Reducing Agent In High Performance Concrete

Concrete is one of the most widely used building materials in the world.Nowadays,with the rapid development of science and technology,higher building use requirements and harsh service environment have higher requirements for concrete performance.High-performance concrete(HPC)was born in the late 1980s.It has many excellent characteristics such as high durability,high workability,and high strength.In recent years,it has been widely used in various projects all over the world.Water reducing admixture can reduce the water cement ratio of concrete,improve the strength and durability of concrete,which is indispensable in the development of high performance concrete.At present,the proportion of polycarboxylic acid based water reducing admixture is continuously increasing in my china,reaching 77.6%in 2017,which is close to the level of western developed countries.How to use water reducing admixture accurately and efficiently is an important aspect of the development of high-performance concrete.This article uses the commonly used building materials in Harbin to prepare 6groups of high-performance concrete with different mix ratios of PC-HB water reducing admixture at 0%,0.1%,0.2%,0.3%,0.4%,0.5%.The effect of PC-HB with different dosages on high performance concrete is studied from the three aspects of working performance,mechanical properties and durability,slump,slump-flow,compressive strength,split tensile strength,freeze-thaw cycle tests.A number of experiments and related research conclusions are as follows:(1)PC-HB water reducing admixture can effectively improve the performance of high-performance concrete,it can effectively reduce the water-cement ratio of concrete and improve the fluidity of concrete.When the content of PC-HB is 0.3%,it can improve that the performance of high-performance concrete is most obvious.(2)PC-HB water reducing admixture can significantly improve the compressive strength and splitting tensile strength of high-performance concrete,and with the increase of PC-HB water reducing admixture content,the mechanical properties of high-performance concrete also increase first and then decrease.PC-HB water reducing admixture has a rapid development for the early strength of high-performance concrete.When the content of PC-HB water-reducing admixture is 0.2%,the mechanical properties of high-performance concrete reach the maximum.The splitting tensile strength and compressive strength of high-performance concrete have a good correlation.The empirical formula is?_ts=0.377?_cc^0.504,and the correlation coefficient is 0.925.(3)PC-HB water reducing admixture can enhance the frost resistance of high-performance concrete to a certain extent,but the range of improvement is limited and there is no clear rule between different dosages.(4)Considering the effects of PC-HB water-reducing agent on the working performance,mechanical properties and durability of high-performance concrete,the overall performance of high-performance concrete is the best when the PC-HB water-reducing agent is 0.2%.