Durability and life cycle evaluation of self-compacting concrete containing fly ash as GBFS replacement with alkali activation

摘要

Nowadays, geopolymer with alkali activation binders are introduced as alternative environmentally friendly construction materials to the ordinary Portland cement for solving the carbon dioxide emission and high energy consumption problems. In the construction sectors worldwide, the durability of concrete is the major concern. Concretes produced by recycling the agricultural and industrial wastes were shown to be environmentally friendly with improved durability performance. In this view, present paper examines the effects of fly ash (FA) as replacement agent to GBFS on the durability performance of synthesized self-compact alkali-activated concrete (SCAACs). Six concrete mixes each with a different percentage of FA (30, 40, 50, 60 and 70%) in place of GBFS were designed. A control mixture with 100% GBFS content was used as base specimen to compare other five mixes. Properties such as filling and passing ability, compressive strength, drying shrinkage, carbonation depth and resistance to sulfuric acid were measured. The life cycle of proposed SCAACs were assessed in terms of CO2 emission, cost and saving energy. The resilience and the workability of the SCAAC mixtures were improved when FA was substituted with GBFS at 40%, 50% and 60%. Addition of FA could largely enhance the SCAACs durability and exhibit superior performance against sulphuric acid attack. Likewise, concrete mixtures containing FA of 50% and above showed reduction in CO2 emission over 20%, cost about 15% as well as energy consumption almost 18%. It was concluded that by substituting GBFS by FA a potential solution to the issue of trying to reduce CO2 emission and contribution to a healthier environment can be achieved. (C) 2019 Elsevier Ltd. All rights reserved.