Study on retardation of a quaternary cementitious materials system for special shotconcrete
The effect of different retarders on the setting time of composite quick-hardening and early-strength cement paste at room temperature was studied.The hydration of cement was delayed by compounding a composite retarder.The products of ce ment hydration at different ages like Ca(OH)2 and AFt were analyzed by the setting time,hydration temperature peak,XRD and SEM.The effect of composite retarder components on the retardation mechanism of cement paste was discussed.The results show that the"citric acid-boric acid-β-cyclodextrin"retarder system can greatly inhibit the early C3S hydration.The reduction of Ca(OH)2 generation and the increase of adsorption amount make the Ca(OH)2 in the cement paste due to the synergistic effect.The con-centration of Ca(OH)2 was greatly reduced,which early hydration rate was effectively reduced and has a good retarding effect.
quaternary cementitious systemcomposite cementitious materialscomposite retardercement hydrationsetting time
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维普
