Preparation And Property Control Of WPC With Fast Hardening And Early Strength

White Portland cement（WPC）is widely used in the integrated engineering of decorative structure,but its lack of fast hardening and early strength limits its application range.For a long time,the research progress of rapid hardening and early strength cement of silicate system has been slow,and the preparation of prefabricated building parts has an urgent demand for Portland cement with rapid hardening and early strength.In this paper,XRD-Rietveld quantitative analysis,isothermal calorimeter,Microanalysis test and other methods were used to study the influence of mineral composition on the hydration properties and compressive strength of WPC,and the rapid hardening and early strength WPC clinker with high early strength was prepared.The effect of wollastonite on fast hardening and early strength WPC clinker was studied.The effect of WPC clinker mixed with dihydrate gypsum on the strength of white Alite-ye’elimite cement clinker was discussed.The results show that:（1）Changing the content of C₃S and C₃A in the mineral composition of WPC clinker,WPC has the highest early strength when the best ratio is achieved.In this chapter,it is found that when the mineral composition of the pre-designed fast hardening and early strength WPC clinker is designed,the content of C3S should be set to about 80%,while the content of C₃A should be set to about 10%.The mineral composition of the final clinker is approximately C₃S（74.9%）,C₂S（8.5%）,C₃A（5.6%）and ACn（11%）.The 3d compressive strength of the cement paste reaches 46.9 MPa,which has early strength performance.（2）Wollastonite as calcium silicate raw material instead of limestone can not only reduce carbon emissions,but also improve the early strength of cement.Due to the chemical structural characteristics of the main component of wollastonite CaO·SiO₂,doped wollastonite can play its role of seed crystal in the process of cement calcination to promote the formation of C₃S,improve the burnability of fast hardening and early strength WPC clinker,and increase the content of C₃S in clinker.An appropriate amount of wollastonite can increase the cumulative hydration heat of WPC without affecting the color of clinker,and improve the early compressive strength of cement.（3）The early strength of white Alite-ye’elimite clinker prepared by secondary calcination of industrial clinker and trial clinker mixed with dihydrate gypsum was significantly improved.The 3d compressive strength of industrial clinker increased from 38.0 MPa to 45.9 Mpa after secondary calcination.The 3d compressive strength of the trial clinker increased from 46.9 MPa to 60.9 MPa.Because the main mineral phase of white Alite-ye’elimite cement clinker is Alite,in addition to high early strength,the later strength is also guaranteed.