Increasing emphasis on sustainability of the built environment has resulted in attempts to drastically reduce the cement consumption in concrete and replace it with waste/recycled materials. This study reports the development of concretes with cement free binders (CFB) and the evaluation of their properties. A Class F fly ash and a ground granulated blast furnace slag (GGBFS) are used as the binding materials. The activating agent used in this study is sodium hydroxide (NaOH), at concentrations ranging from 6 M to 10 M. The optimal temperature and curing duration required to achieve desirable compressive strengths of CFB concretes are reported. The influence of the binding material and the concentration of the activator on the compressive strength and porosity of the CFB concretes are studied. The compressive strength of CFB concretes with fly ash as the binding material increases with increase of activating solution concentration but for CFB concretes with GGFBS as the binder, activation with 8 M NaOH is seen to result in the highest compressive strength. The strength-porosity relationship of CFB concretes shows an exponential trend, similar to that of conventional cement based materials. Microstructure and the phase composition of the reaction products are also discussed.
ASJC Scopus subject areas
- Materials Science(all)
Kwa kuongezeka kwa msisitizo juu ya uendelevu wa mazingira yaliyojengwa, majaribio ya kupunguza kwa kiasi kikubwa matumizi ya saruji katika saruji na kuibadilisha na taka au vifaa vilivyotengenezwa upya. Utafiti huu unaripoti maendeleo ya saruji na simenti huru binders (CFB) na tathmini ya mali zao. F-Class fly ash na granulated high furnace slag (GGBFS) hutumiwa kama vifaa vya kuunganisha. Katika utafiti huu, kemikali ya activating kutumika ni sodium hydroxide (NaOH) katika viwango mbalimbali kutoka 6M hadi 10M. joto bora na muda wa kuimarisha zinahitajika kufikia compressive nguvu ya CFB. Ushawishi wa nyenzo ya kuunganisha na mkusanyiko wa activator juu ya nguvu ya compressive na porosity ya saruji CFB ni alisoma. Kwa mfano, nguvu ya compressive ya saruji ya CFB na fly ash kama nyenzo ya kuunganisha huongezeka na kuongezeka kwa mkusanyiko wa suluhisho la uanzishaji, lakini kwa saruji ya CFB na GGF-B-S kama kiunganishi, uanzishaji na 8M NaOH huonekana kusababisha nguvu ya juu ya compressive. Uhusiano wa nguvu-porosity ya CFB saruji inaonyesha mwelekeo exponential, sawa na ile ya kawaida saruji msingi vifaa. Microstructure na awamu ya muundo wa bidhaa za athari pia ni kujadiliwa. ASIC Scopus: Sayansi ya Vifaa