Aiming at the problem that the strength of cement pastes commonly used in cementing under negative temperature environment develops slowly or even stops hydration,this paper studies the slurry properties of lithium salt(TSL)-sulfoaluminate cement(SAC)slurry system and the mechanical properties of cement stone at 4℃ and-10℃,and tests the hydration temperature rise and cumulative heat release of cement.The hydration process of cement was analyzed by X-ray diffractometer(XRD),thermogravimetric analyzer(TG/DTG)and scanning electron microscope(SEM),and the feasibility of application of TSL-SAC cement system in negative temperature cementing project was demonstrated.The results show that the slurry performance of TSL-SAC cement slurry system is well.When the content of TSL is 3％of SAC,the 48 h compressive strength can reach 23.01±0.47 MPa at 4℃ and 3.98±0.07 MPa at-10℃,which meets the requirements of cementing construction.At the same time,the hydration temperature rise and cumulative heat release of cement were effectively reduced by the introduction of temperature control materials.The maximum hydration temperature rise was reduced by 27.62％,and the maximum hydration temperature rise delay was 320.67％.The mechanism of TSL promoting the hydration reaction of SAC is that it increases the generation of gel hydration products of iron glue and aluminum glue in cement stone,promotes the growth and crystallization of AFt,forms a low crystallinity CaCO3 protective layer and reduces the carbonization of CH.TSL-SAC cement slurry has the potential of application in negative temperature cementing environment,and this study provides a certain experimental and theoretical basis for cementing in negative temperature area.
维普
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