The Efficiency of Recycling Expired Cement Waste in Cement Manufacturing: a Sustainable Construction Material

Abstract

Reusing expired cement (EC) in cement manufacturing is an alternative way for managing such industrial waste, so this process contributes to preserving the environment and reducing the need for raw materials which creates an innovative solution in circular economy strategies as well as producing a sustainable material. The purpose of this study is to investigate the possibility of using EC as mineral additives for the manufacture of new cement. The different formulations of cements are the results of CEMI subtraction up to 35% by weight with the EC. These modified cements have passed the same tests as a characterization of a CEMII. The obtained results show that EC changes the characteristics of cementitious materials (anhydrous, paste, and mortar). The new cement produced fulfilled the requirements in terms of chemical characteristics. In addition, the decrease in strength caused by EC incorporation is in accordance with standards. It can be stated that EC plays the role of a diluting agent in the new cement. Environmentally, it may be more efficient to use EC as an ecofriendly additive material.

Fresh Properties of Self-Consolidating Expired Cement-Fly Ash Cold Bonded Lightweight Aggregate Concrete With Different Mineral Admixtures

“…Unused or improperly kept cement will expire if not used within the recommended storage term and can be considered waste material. Expired cement is the cement that has been used after its expiration date, which can be anywhere from (3)(4)(5)(6) months. It is possible for cement to partially hydrate when stored due to moisture penetration.…”

“…It is possible for cement to partially hydrate when stored due to moisture penetration. This means that when the cement finally mixed and used, it will have less hydration capacity [3].…”

“…This is primarily due to the spherical shape of ALA as opposed to the angular features of NA [8]. To obtain the same artificial lightweight concrete (ALAC) workability, the normal aggregate concrete (NAC) mixture should be adjusted, either by increasing the cement paste volume or the amount of superplasticizer, but this increases the cost [3]. Kockal and Ozturan discovered that when NA was replaced with ALA, the amount of superplasticizer needed to obtain the required slump decreased by roughly 8% [9].…”