The hydration characteristics by thermal analysis (DTA) were determined, and an isothermal calorimeter (IC) was used to study the pastes. The experimental results indicate: (1) The main hydration products of SSC are C...The hydration characteristics by thermal analysis (DTA) were determined, and an isothermal calorimeter (IC) was used to study the pastes. The experimental results indicate: (1) The main hydration products of SSC are C-S-H (I) gel with a low Ca/Si ratio, crystalline Thomsonite-type and AFt-type phases containing certain alkali cations; (2) No phases of the AFm-type and high alkaline Ca (OH)(2) in SSC system could benefit the hydrated cements to improve its strength and durability; (3) Crystalline Thomsonite-type and AFt-type phases containing Na+ will greatly reduce free alkali and alleviate the harmness of alkali aggregate reaction (AAR) in SSC system; (4) Similar to ordinary Portland cement (OPC), the hydration process of SSC could be classified into five stage: initial, induction, acceleration, deceleration and decay; (5) Regardless of the activator used, the apparent activation energy is higher with the increased slag in cement system, and the rising temperature could promote the hydration of SSC.展开更多
Unilateral sulfate attack of cementitious materials containing 40% slag with different water to binder ratios was investigated. The results showed that the degradation of slag blended cement pastes was nearly from the...Unilateral sulfate attack of cementitious materials containing 40% slag with different water to binder ratios was investigated. The results showed that the degradation of slag blended cement pastes was nearly from the corners of paste surface with cracking and spallings, water-to-binder（w/b） ratio made a significant sense to the damage that low w/b ratio led to little weight loss, less cracking and spalling damage and vice versa. Microstructural experimental results demonstrated that in the three different stages of sulfate attack, degradation of pastes was primarily associated with the migration behavior and bonding configuration of aluminum, in the early ages Al was mostly present in C-（A）-S-H, and thus, the damage of pastes hardly appeared while at later ones Al had been largely transferred from C-（A）-S-H into AFt, leading to expansive damage.展开更多
基金Funded by the State"the Ninth-Five-year Plan "Item (96-535-33-5)
文摘The hydration characteristics by thermal analysis (DTA) were determined, and an isothermal calorimeter (IC) was used to study the pastes. The experimental results indicate: (1) The main hydration products of SSC are C-S-H (I) gel with a low Ca/Si ratio, crystalline Thomsonite-type and AFt-type phases containing certain alkali cations; (2) No phases of the AFm-type and high alkaline Ca (OH)(2) in SSC system could benefit the hydrated cements to improve its strength and durability; (3) Crystalline Thomsonite-type and AFt-type phases containing Na+ will greatly reduce free alkali and alleviate the harmness of alkali aggregate reaction (AAR) in SSC system; (4) Similar to ordinary Portland cement (OPC), the hydration process of SSC could be classified into five stage: initial, induction, acceleration, deceleration and decay; (5) Regardless of the activator used, the apparent activation energy is higher with the increased slag in cement system, and the rising temperature could promote the hydration of SSC.
基金Funded by the National Key Research Program(973 Program)(No.2015CB655101)National Natural Science Foundation of China(No.51379163)
文摘Unilateral sulfate attack of cementitious materials containing 40% slag with different water to binder ratios was investigated. The results showed that the degradation of slag blended cement pastes was nearly from the corners of paste surface with cracking and spallings, water-to-binder（w/b） ratio made a significant sense to the damage that low w/b ratio led to little weight loss, less cracking and spalling damage and vice versa. Microstructural experimental results demonstrated that in the three different stages of sulfate attack, degradation of pastes was primarily associated with the migration behavior and bonding configuration of aluminum, in the early ages Al was mostly present in C-（A）-S-H, and thus, the damage of pastes hardly appeared while at later ones Al had been largely transferred from C-（A）-S-H into AFt, leading to expansive damage.
