The potency of recycled aggregate in new concrete: a review

Abstract

Purpose This paper aims to review the effect of using recycled aggregates (RA) on the properties of recycled aggregate concrete (RAC) following the steady rise in global demand for concrete and the large generation of construction and demolition waste. Design/methodology/approach This study reviewed relevant literature of research work carried out by previous researchers, leading to a deeper understanding of the properties of both RA and RAC. The properties of RA and RAC reported in the various studies were then compared to their corresponding natural aggregate (NA) and natural aggregate concrete, as well as the specifications provided in different codes of practice. In addition, the mix design methods appropriate to RAC and the cost implication of using RA were reviewed. Findings Findings show that the contribution of RA to strength appears inferior in comparison to NA. The shortcoming is attributed to the mortar attached to the RA, which raises its water absorption capacity and lowers its density relative to those of NA. However, it has been reported that the use of regulated quantity of RA, new mixing and proportioning methods, the addition of admixtures and strengthening materials such as steel fibres, can improve both mechanical and durability properties of RAC. Cost evaluation also showed that some savings can be realized by using RA instead of NA. Originality/value This research serves as a guide for future works and suggests that the use of RA as aggregate in new concrete is technically possible, depending on the mix design method adopted.

Analysis on the Strength of Cement Mortar Mixed with Construction Waste Brick Powder

“…e main components of construction waste are bricks and concrete blocks [2][3][4][5]. In recent years, many studies have been focused on investigating the properties and reuse methods of waste concretes, and correspondingly the recycling rate of waste concretes is high [6][7][8][9][10]. Researches on waste bricks have been limited to their applications as recycled aggregate, or the effect of waste brick powder content on the performance of cement-based materials [11][12][13].…”

Evaluation of conventional and equivalent mortar volume mix design methods for recycled aggregate concrete

“…Concrete is an essential construction material. However, the production of concrete causes huge environmental challenges arising from aggregates and cement requirements [1,2].…”

“…Fathifazl et al [5] also argued that the devastating effect of RA on the elastic modulus of RAC has not been salvaged by any known mix design technique except the equivalent mortar volume (EMV) approach. Thus, in a review carried out, Anike et al [1] concluded that factors such as grade and composition of parent concrete, mixing method, content and moisture condition of RA, and presence of admixtures definitely influence the properties of RAC as reflected in the results available in literature.…”

Effect of mix design methods on the mechanical properties of steel fibre-reinforced concrete prepared with recycled aggregates from precast waste

“…Recycling of concrete waste remains an important step in the pursuit of global environmental sustainability [1]. This is because, the use of recycled aggregates (RA) not only saves the diminishing natural resources but also offers a relief to the pressure imposed on landfills [2].…”