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Composition, morphology, and structure of hydration products in hardened pastes of three kinds of blended cement(cement-silica fume, cement-quartz powder and cement-silica fume-quartz powder) hydrated under different curing regimes(standard curing, 90 ℃ steam curing, 200 ℃ and 250 ℃ autoclave curing) were investigated by X-ray diffraction and field emission scanning electron microscope equipped with EDAX system. Results showed that the main hydration products in three kinds of hardened pastes under standard curing condition are all C-S-H gels, CH, and AFt. Under 90 ℃ steam curing condition, the main hydration products of cement-silica fume and cement-silica fume-quartz powder are C-S-H gels, whereas those of cement-quartz powder are C-S-H and CH. Under 200 or 250 ℃ autoclave curing condition, no obvious crystallized CH phase is found in hardened pastes of three kinds of blended cement, and C-S-H gels are transformed into one or more crystalline phases such as tobermorite, jennite, and xonotlite. The chemical composition and morphology of these crystalline phases depend on the composition of mixture and autoclave temperature.
Composition, morphology, and structure of hydration products in hardened pastes of three kinds of blended cement (cement-silica fume, cement-quartz powder and cement-silica fume-quartz powder) hydrated under different curing regimes , 200 ° C and 250 ° C autoclave curing) were investigated by X-ray diffraction and field emission scanning electron microscope equipped with EDAX system. Results showed that the main hydration products in three kinds of hardened pastes under standard curing conditions are all CSH gels, CH , and AFt. Under 90 ° C steam curing condition, the main hydration products of cement-silica fume and cement-silica fume-quartz powder are CSH gels, those of cement-quartz powders are CSH and CH. Under 200 or 250 ° C autoclave curing condition, no obvious crystallized CH phase is found in hardened pastes of three kinds of blended cement, and CSH gels are transformed into one or more crystalline phases such as tobermorite, jen nite, and xonotlite. The chemical composition and morphology of these crystalline phases depend on the composition of mixture and autoclave temperature.