Effect of different steam curing temperatures on ultrafine fly ash-cement mortar
To investigate the performance of ultra-fine fly ash(UFA)cement mortar under different steam curing temperatures,the ef-fects of 20％,30％,and 40％UFA admixtures on the flowability and mechanical properties of UFA cement mortar were studied at stan-dard curing 20 ℃,steam curing 50 ℃,60℃,and 70℃,respectively.The hydration and UFA action effects of UFA cement composite cementitious materials were analyzed using chemical combined water content method and thermogravimetric method(TG-DTG).The results show that the flowability of UFA cement mortar increases with the increase of UFA content;Under the same dosage,steam cur-ing improved the early strength of UFA cement mortar compared to standard curing;The 28 d flexural and compressive strength of UFA specimens steamed at 50 ℃ and 60 ℃ at the same temperature is lower than that of the control group.The 28 d flexural and compressive strength of UFA-20％at 70 ℃ reaches its maximum at 10.0 MPa and 53.1 MPa,respectively,and is higher than that of the control group;Compared with the 1d age group,the UFA in the 28 d age group steam cured specimens participated significantly in the hydra-tion reaction,and steam cured promoted the degree of slurry hydration and increased the volcanic ash activity of UFA particles.
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