Influence of Cementitious System Composition on the Retarding Effects of Borax and Zinc Oxide

Materials

FeraidonF. Ataie¹ 

[1]Concrete Industry Management Program, California State University, Chico, CA 95929, USA

关键词: zinc oxide;    borax;    set time;    heat of hydration;    calcium aluminate cement;    calcium sulfoaluminate cement;   

DOI  :  10.3390/ma12152340

来源: DOAJ

【 摘 要 】

This research investigated the retarding impact of zinc oxide (ZnO) and borax (Na₂[B₄O₅(OH)₄]·8H₂O) on hydration of Portland cement, calcium aluminate cement (CAC), and calcium sulfoaluminate cement (CSA). Heat of hydration of cement paste samples with and without ZnO and borax was used to measure the influence of ZnO and borax on the set time of these cementitious systems. It was found that both ZnO and borax can retard the set time of Portland cement systems; however, ZnO was shown to be a stronger set time retarder than borax for these systems. ZnO did not show any retarding impact on CAC and CSA systems while addition of borax in these systems prolonged the set time. It was concluded that ZnO does not poison the nucleation and/or growth of CSA and CAC hydration products. We suggest that borax retards the cement set time by suppressing the dissolution of cement phases.

【 授权许可】

Unknown