Enhancement of early-age strength of the high content fly ash blended cement paste by synergistic effect of polysystem of alcamines and C-S-H-PCE nanocomposite seeds
Although fly ash has many advantages such as reducing hydration heat and carbon emission,However,the slow reaction of volcanic ash will reduce the hydration degree of the whole system at high dosage(typically＞30％in mass),resulting in slow development of early-age strength.Therefore,it is necessary to develop the highly-effificient and environmental-friendly method for the enhancement of the early-age strength of cement and fly ash paste.The mechanism and effect of alcamines(TEA,TIPA)and C-S-H-PCE on the early hydration of cement(55％)and high content fly ash(45％)and fly ash itself were assessed in terms of compressive strength,hydration heat,setting time,XRD,TG-DTG,ICP and SEM.The results show that alcamines(TEA,TIPA)and C-S-H-PCE exhibit a synergistic enhancement ef-fect on the hydration degree of cement and the reaction degree of fly ash.The combination of C-S-H-PCE and alcamines(TEA,TIPA)could promote the formation of AFt,and played a synergistic effect on the improvement of early compressive strength,which is much high-er than the sum of individual effects of alcamines(TEA,TIPA)and C-S-H-PCE.Moreover,the underlying mechanism of the synergistic effect is revealed through this study.C-S-H-PCE provides nucleation sites to promote cement hydration and accelerate AFt formation.On the one hand,alcohol amines(TEA,TIPA)promote the conversion of AFt into AFm,produce more CH,and accelerate the dissolution of FA in pore solution.On the other hand,they complexate with Al and Fe,and accelerate the dissolution of activated alumina and silica in FA glass phase into pore solution to participate in pore-ash reaction,and form additional C-S-H gel.
high content fly ashTEATIPAC-S-H-PCEearly-age strengthsynergistic effect
万方数据
维普
