Study On Application Of Super Early Strength Polycarboxylate Superplasticizer In Sleeve Grouting Material

With the development of the assembly building,as the key node of the assembly building,the application of the steel sleeve grouting connection in the assembly building.Therefore,the requirements of the sleeve grouting material are also increasing,the traditional sleeve grouting material in the application process exposed many problems,so the development of high performance grouting material for the development of assembly building is essential.Compared with traditional high performance water reducing agent,polycarboxylate superplasticizer has the advantages of high water reducing rate,strong ability to collapse,flexible design of molecular structure and so on.Polycarboxylic acid type water reducer is a kind of molecular structure of comb shaped,containing carboxyl polymer surfactant,the unique molecular structure makes this kind of water reducing agent has more features.With high performance mortar and concrete market demand,to reduce water reducing agent properties,dispersion properties and the mechanical properties improved significantly,the research on ultra early strength polycarboxylate superplasticizer has become a hot research topic.It is urgent to research and develop early strength,high water reducing rate,good adaptability and strong ability to resist collapse.Based on the design of molecular structure of polycarboxylate superplasticizer,by changing the molecular methyl allyl polyethenoxy ether long side chain,the graft can improve the early strength of concrete amido groups of single factor synthesis test.And then determine the optimal synthesis scheme using the orthogonal test method,the synthesis of small material content is 0.3 %,dosage lead 0.6 %,acid ether ratio is 5.5 : 1,AM substitution rate is 20 %,the macromonomer proportion ofn(HPEG2400)?n(HPEG5000)= 0.5 : 1,chain transfer agent was 1.4 %,and in the best plan to synthesize ultra early strength polycarboxylate superplasticizer PC-S.By changing the dosage of polycarboxylate superplasticizer,studied the influence of polycarboxylate superplasticizer on the sleeve grouting material performance,to determine the optimal dosage of super early strength polycarboxylate superplasticizer is 0.16 %.Through the experimental study on the early strength of mortar composition changes with the content of the impact on performance,and then determine the optimal scheme of compound early strength agent by orthogonal test,namely the content of 0.5 % sodium sulfate,sodium nitrite content is 0.5 %,calcium content is0.5 %.Through the contrast test,it is found that the early strength of the grouting material can be improved by adding PC-S super early strength polycarboxylate superplasticizer,but the strength of 28 d is not very different.The early strength of the sleeve grouting material mixed with PC1601+ early strength agent also increased to some extent,but the strength of 28 d decreased slightly.