Effect of mineral additives and two-stage mixing on the performance of recycled aggregate concrete
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ORIGINAL ARTICLE
Effect of mineral additives and two‑stage mixing on the performance of recycled aggregate concrete Rayhan Md. Faysal1 · Mohammed Maslehuddin2 · Mohammed Shameem2 · Shamsad Ahmad1 · Saheed Kolawole Adekunle1 Received: 9 October 2019 / Accepted: 30 April 2020 © Springer Japan KK, part of Springer Nature 2020
Abstract There is an increasing tendency to use recycled aggregate to produce concrete due to diminishing sources of natural aggregate. The properties of recycled aggregate concrete (RAC) are inferior to that of normal aggregate concrete. Several strategies including the use of supplementary cementitious materials (SCMs) are adopted to improve the properties of RAC. The two-stage mixing approach (TSMA) is also used as an improvement strategy. The present study was aimed to examine the individual and combined effects of using SCMs and TSMA on the fresh and hardened properties of RAC. Three SCMs, namely, fly ash, ground granulated blast furnace slag, and silica fume were used with and without TSMA. The experimental data indicated the beneficial effect of SCMs and TSMA on workability, strength, shrinkage, and durability of RAC. Further, the cost per unit strength of the RAC with SCMs and TSMA was less than that of RAC without any treatment. The use of developed RAC will lead to technical, economic, and environmental benefits. Keywords Mineral additives · Supplementary cementitious materials · Two-stage mixing approach · Recycled aggregate · Concrete · Mechanical properties · Durability
Introduction Coarse aggregate is one of the ingredients that is used in highest amount for producing normal concrete mixtures. However, the depleting natural sources of coarse aggregates necessitates to find alternative sources [1, 2]. At the same time, the disposal of construction and demolition waste * Shamsad Ahmad [email protected] Rayhan Md. Faysal [email protected] Mohammed Maslehuddin [email protected] Mohammed Shameem [email protected] Saheed Kolawole Adekunle [email protected] 1
Civil and Environmental Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
2
is often costly and hazardous for the environment [3]. To address these issues, several studies have been carried out towards utilizing coarse aggregates extracted from the construction and demolition wastes in producing concrete. The coarse aggregate extracted from the construction and demolition wastes to produce new concrete is commonly termed as recycled aggregate (RA) [4–7]. The studies conducted to evaluate the performance of recycled aggregate concrete (RAC) [8–12] indicated that the quality of RAC is inferior to that of natural aggregate concrete (NAC), mainly due to the weak interfacial transition zone (ITZ) between the old mortar on the surface of the RA and the new mortar. The main reason behind a weak ITZ is the pesence of microcracks and pores in the old mortar adhe
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