Study Of The Adaptability Of Alite-sulphoaluminate Cement And Superplastizers

In this thesis, the main minerals C4 A 3 S, C3S and C2S of alite-sulphoaluminate cement clinker were synthesized in the laboratory and the adsorption characteristics of three sorts of superplasticizers, which include naphthalene sulfonates superplasticizer (FDN), amino sulphonate formaldehyde condensate superplasticizer (AS) and poly carboxylate superplasticizer(PC), were studied. The alite-sulphoaluminate cements of different minerals compositions as group A and B were designed and synthesized by changing C4 A 3 S, C3Så’ŒC2S minerals content of alite-sulphoaluminate cement clinker. In group A, C3S mineral content was 60%, 45% and 30% respectively, C2S mineral content was changed corresponsively, while other minerals content was unchanged; in group B, C4 A 3 S mineral content was 5%, 15% and 20% respectively, C2S mineral content was changed corresponsively, while other minerals content was unchanged. The adaptability of alite-sulphoaluminate cements and superplasticizers was studied by analyzing some physical characteristics including the water requirement of standard consistency, the compressive strength, the fluidity and fluidity loss with time of alite-sulphoaluminate cement before and after being mixed into FDN, PC and AS.The results showed that, the adsorptive capacity of FDN and AS on C4 A 3 S, C3S, C2S minerals and alite-sulphoaluminate cement can be measured by ultraviolet-visible absorption spectrometry, but that of PC cannot be measured. The utmost adsorptive capacity of FDN and AS on C4 A 3 S, C3S and C2S minerals were sorted as C4 A 3 S>C3S>C2S. The utmost adsorptive capacity of FDN and AS on C4 A 3 S mineral was much more than that on C3S and C2S minerals, while that on C3S mineral was little more than that on C2S mineral. The utmost adsorptive capacity of FDN on C3S and C2S minerals decreased with time, but that on C4 A 3 S mineral increased with time. The utmost adsorptive capacity of AS on C4 A 3 S, C3S and C2S minerals increased with time. When the same sort of cement monomineral adsorbed different sorts of superplasticizers, the utmost adsorptive capacity of AS on the monomineral was obviously more than that of FDN.When alite-sulphoaluminate cement adsorbed FDN and AS, the adsorptive capacity decreased to less extent with the reduction of C3S in clinker, but the adsorptive capacity increased to more extent with the increment of C3S in clinker. C4 A 3 S mineral content in alite-sulphoaluminate cement clinker impacted more obviously on adsorptive capacity of FDN and AS on the cement.On the condition that C4 A 3 S mineral content in alite-sulphoaluminate cement clinker was fixed, the cement with more C3S mineral content possessed higher each age strength; and on the condition that C3S mineral content in alite-sulphoaluminate cement clinker was fixed, the cement with less C4 A 3 S mineral content possessed lower early-strength,higher later-strength. After mixing FDN into alite-sulphoaluminate cement, the cement possessed the most increase rate of each-stage-strength,the least fluidity loss and the best adaptability of FDN, when C4 A 3 S mineral content in alite-sulphoaluminate cement clinker was 5%.After mixing AS into alite-sulphoaluminate cement, the compressive strength of the two group increased to differet extent. For the alite-sulphoaluminate cement with 5% C4 A 3S, it possessed the most increase rate of each-stage-strength,the least fluidity loss and the best adaptability of AS. After mixing PC into alite-sulphoaluminate cement, the 28 day age strength of the two group decreased to differet extent.The adaptability of alite-sulphoaluminate cement of different minerals compositions and superplasticizers is difference.When C4 A 3 S mineral content in alite-sulphoaluminate cement clinker was higher, it impacted the most dramatically on the strength and fluidity of the cement after mixing into three sorts of superplasticizers, the adaptability of the cement and superplasticizers was more bad; while the adaptability of the cement with more C3S and less C4 A 3S and superplasticizers was more better.