Development of Sustainable and Low Carbon Concretes for the Gulf Environment

Abstract

Massive construction activities in the countries of Arabian Peninsula have raised legitimate concerns about the associated impact on the environment in terms of emission of greenhouse gas and other environmental factors. As concrete is the most commonly used building materials, reduction of eCO2 and other impacts are a necessity. Use of high volume of Supplementary Cementitious Materials (SCMs) such as GGBS, fly ash, microsilica and rice husk ash together with Portland cement in different combinations could reduce the eCO2 substantially. Use of specific sustainable practices such as utilizing finer particles of unwashed crushed limestone fine aggregates, recycled concrete aggregate (RCA), additionally entrained air and utilizing higher ambient temperature to design concrete strength and durability parameters could be the key strategies to reduce the impact of the environmental factors.The effect of different type of cementitious combinations together with finer particles of unwashed sand, RCA, entrained additional air and elevated curing temperature were tested on concretes and validated against a commonly used concrete mix proportion and a set of specific performance criteria based in the Arabian Gulf. The microstructure of the cement pastes and mortars made of similar cementitious combinations were analysed using techniques like TGA, SEM and MIP.The engineering and durability properties of the selected concrete mixes were validated against the environmental performance and corresponding cost effectiveness based on the regional implications of Arabian Peninsula. To evaluate the environmental performance of the concrete a concept of strength/eCO2 index and a set of sustainability environmental factors (ESF) are introduced.It was found that concrete mix proportion containing 15% Portland cement, 70% GGBS and 15% rice husk ash of total cementitious materials combining with other associated sustainable practices such as RCA, additional finer particles of ‘unwashed’ crushed limestone fine aggregates and entrained air met the overall performance of engineering, durability and environmental parameters compared to the control mix and conditions. A concrete with 85% GGBS could be another alternative with the most cost effective scenarios.

Date of Award	16 Jan 2014
Original language	English
Awarding Institution	University of Bath
Supervisor	Kevin Paine (Supervisor) & Pete Walker (Supervisor)