Research On The Properties Of Super Early-Strength Cement-Based Grout

Super high early strength grouting mortar is composed by cement-based materials, fine sand, outside admixtures, superplasticizer,thickening time control agent, early strength agent, defoamer and other materials. It has strongpoint of fluidity when water added. It could grow super high strength in short time. This mortar could be used to concrete rapid mending, secondary grouting of equipments, recently it is being used to pot rubber bearing of high-speed rail, box girders of bearing of confederation bridge and grouting anchor bolt holes of bearing, so super high early strength grouting mortar has very expanse market.This issue is based on complex-system matrix of ordinary Portland cement and sulphoaluminate cement, quartz sand as aggregate to make super high early strength grouting mortar. Adding Lime and HPMC into mortar to prevent bleeding. Because Lime could change to some tiny bobble which adsorb layer of water. Otherwise lime could generate AFt, show minimum inflation and early strength. in order to solve the contradiction of early strength and delayed coagulation, we used to add proper thickening time control agent.Boric acid and tartaric acid as delayed coagulation agent. Li2CO3 as super early strength agent. polycarboxylic acid superplasticizer and deformer. All these made the grout had a good workability. Initial fluidity is above 320mm. After 30min the fluidity is still above 240mm. 2h compressive strength beyond 20MPa, 24h flexural strength beyond 10MPa. The experiment show that the strength fall as the ordinary Portland cement added more. The strength fall as the ordinary sand added more.The experiment test the impervious powder resistance the chloride ion penetration of the concrete which was grouted by mortar thought the NEL- PEU and test the modulus of elasticity through the NM-4B, we also test the content of chloride ion through the NCL-AL. In order to deduce the ability of mortar to rust the steel.XRD and SEM show that there were Ca(OH)₂, AFM and Ca₄Al₆O₁₂SO₄, so we infer that Li_CO₃ work as catalyst accelerating the hydration reaction and grew a lot of hydration product, so mortar had a high compression strength in a short time. Besides we found a little lithium aluminum silicate. It is belong to ceramics, but this result has not been confirmed by now.