Requirements of self-compacting concrete （SCC） applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be s...Requirements of self-compacting concrete （SCC） applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be satisfied by ordinary SCC. In this study, in order to solve the problem, a few principles of SCC design were proposed and the effects of binder amount, fly ash （FA） substitution, aggregate content and gradation on the workability, temperature rise, drying shrinkage and elastic modulus of SCC were investigated. The results and analysis indicate that the primary factor influencing the fluidity was paste content, and the main methods improving the elastic modulusof SCC were a lower sand ratio and an optimized coarse aggregate gradation. Lower adiabatic temperature rise and drying shrinkage were beneficial for decreasing the cement content. Further, based on the optimization of mixture, a C50 grade SCC （with binder amount of only 480 kg/ m3, fly ash substitution of 40%, sand ratio of 51% and proper coarse aggregate gradation （Vs.~0 mm： V10-16 ram： V16.20 mm= 30%： 30%：40%）） with superior workability was successfully prepared. The temperature rise and drying shrinkage of the prepared SCC were significantly reduced, and the elastic modulus reached 37.6 GPa at 28 d.展开更多
The thermo-dynamics of reactions between carbonatite and sodium silicate solution at ordinary temperature （25℃） were investigated. The calculated results indicate that at ordinary temperature, the reactions between...The thermo-dynamics of reactions between carbonatite and sodium silicate solution at ordinary temperature （25℃） were investigated. The calculated results indicate that at ordinary temperature, the reactions between dolomite, calcite, Ca2＋ and Mg2＋ in carbonatite and H4SiO4, tl3SiO4- and H2SiO42- in sodium silicate solution to form the cementitious products of hydrated calcium silicate or hydrated magnesium silicate all possibly happen; among these reactions, the reactions to form gyrolite （2CaO.3SiO2.2.5H2O） and serpentine （3MgO.2SiO2-2H20） are the most possible to occur. Further, the dissociation degree of dolomite and calcite and the activity of H3SiO4 , H2SiO42- and H4SiO4 ions are the key factors to influence the reactions.展开更多
基金Funded by National Natural Science Foundation of China(Nos.U1134008 and 51302090)the Fundamental Research Funds for the Central Universities(No.2015ZJ0005)
文摘Requirements of self-compacting concrete （SCC） applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be satisfied by ordinary SCC. In this study, in order to solve the problem, a few principles of SCC design were proposed and the effects of binder amount, fly ash （FA） substitution, aggregate content and gradation on the workability, temperature rise, drying shrinkage and elastic modulus of SCC were investigated. The results and analysis indicate that the primary factor influencing the fluidity was paste content, and the main methods improving the elastic modulusof SCC were a lower sand ratio and an optimized coarse aggregate gradation. Lower adiabatic temperature rise and drying shrinkage were beneficial for decreasing the cement content. Further, based on the optimization of mixture, a C50 grade SCC （with binder amount of only 480 kg/ m3, fly ash substitution of 40%, sand ratio of 51% and proper coarse aggregate gradation （Vs.~0 mm： V10-16 ram： V16.20 mm= 30%： 30%：40%）） with superior workability was successfully prepared. The temperature rise and drying shrinkage of the prepared SCC were significantly reduced, and the elastic modulus reached 37.6 GPa at 28 d.
基金Funded by the National Natural Science Foundation of China(No.51402057)
文摘The thermo-dynamics of reactions between carbonatite and sodium silicate solution at ordinary temperature （25℃） were investigated. The calculated results indicate that at ordinary temperature, the reactions between dolomite, calcite, Ca2＋ and Mg2＋ in carbonatite and H4SiO4, tl3SiO4- and H2SiO42- in sodium silicate solution to form the cementitious products of hydrated calcium silicate or hydrated magnesium silicate all possibly happen; among these reactions, the reactions to form gyrolite （2CaO.3SiO2.2.5H2O） and serpentine （3MgO.2SiO2-2H20） are the most possible to occur. Further, the dissociation degree of dolomite and calcite and the activity of H3SiO4 , H2SiO42- and H4SiO4 ions are the key factors to influence the reactions.
