Research On The High-performance Sleeve Grouting Material For Assembly Building

With the development of modern construction industry and the innovation of building technology,assembly building has solved the issues that past prefabricated housing construction quality was low and poor seismic.At the same time,it also owns faster speed of construction,higher quality of precast production,less labor demand quantity and less environment pollution,etc,which will make the assembly building to become the new direction for the future construction industry.Today,most of the assembly buildings use grout sleeve connection technology to connect the precast elements.the sleeve grouting material is the main part of the connector,it has a great influence on the connectors' quality.In engineering applications,it is more inclined to use cement grouting material,it is suitable to construction which close contact with the human,and its cost is relatively low,and it can achieve high fluidity,high strength,high stability and micro expansion.it caters the demand of assembly building sleeve grouting material's properties.Today assembly building is towards the direction of high-level and larger span.And the Technical Specifications for precast concrete structures has been released in Liaoning Province,the Technical Specification makes a clear request to sleeve grouting material for Assembly Building.but,on the market,the workability and mechanical properties of many sleeve grouting materials have not satisfied the requirements of sleeve grouting material for assembly building.This paper is based on the requirements of sleeve grouting material for assembly building in Technical Specifications for precast concrete structures(DB21/T1868-2010),by each material component systematic analysis and optimization,the test finds sleeve grouting material's optimal ratio which applys to assembly building.This paper researchs the workability and mechanical properties of grouting material from aspects of quartz sand gradation,complex cement,sand-cement ratio,water-cement ratio,additives and mineral admixtures.On the basis of the determined ratio,the test explores the grouting material ratio which owns higher compressive strength by wrapping the aggregate.The results show that:when the quartz sand gradation:20 mesh?40 mesh and mesh 40?70 quartz sand mass ratio is 1:0.798,complex cement:42.5 sulphoaluminate cement and 52.5R Portland cement mixed with mass ratio is 9:1,water-binder ratio is 0.26,sand-binder ratio is 0.8,polycarboxylate superplasticizer's dosage is 4‰,sodium tetraborate's dosage is 56‰,hydroxypropylmethylcellulose's dosage is 0,1‰,silicone defoamer's dosage is 2‰,calcium oxide class expander's dosage is 4%,silica fume's dosage is 3%and fly ash's dosage is 5%,the grouting material is the optimal ratio.In order to further improve the compressive strength of grouting material,the test uses 8%of cementitious material with 0.20 water-cement ratio to crap quartz sand surface and mix 7‰ KH-570 silane coupling agent in cementitious material,and maintain more than 5h,then remaining cementitious material and the package of quartz sand mixiand mold.The grouting material made by this method can improve the bonding strength of cement stone and quartz sand surface,and improve the compressive strength of grouting material.The final grouting material ratio owns initial fluidity is 345mm,30min fluidity is 302mm,Id compressive strength is 64MPa,3d compressive strength is 78MPa,28d compressive strength is 105MPa,3h vertical expansion rate is 0.046%,24h vertical expansion rate is 0.17%,it meets the Technical Specifications for precast concrete structures(DB21/T1868-2010).Meanwhile,the test uses grouting sleeve within formulated grouting material to do the uniaxial tensile test.the test results are that steels pulled off and sleeves intact,test indicates that the formulated grouting material can be used as the sleeve grouting material used in the assembly building.