Use of Secondary Lead Recycling Slag As A Construction Material

Abstract

Cement production emits anthropogenic CO2 into atmosphere, leading to global warming. Also, cement manufacturing consumes abundant natural resources. So, it becomes essential to minimize the environmental impact, and atmospheric carbon dioxide as natural resources are getting declined and greenhouse emissions are becoming more evident. Admixtures have opened a new era of mix design of required strength and durability to overcome these ill effects. In past decades, various techniques have been adopted to conserve natural resources by using sustainable engineering approaches. Various waste and SCMs have been used to replace Cement. Efforts have been made to save energy by promoting industrial waste like fly ash, silica fume, rice husk, meta-kaolin, GGBS, etc., which shows similar chemical properties as cement. The use of such pozzolanic material reduces the cost and helps reduce cement consumption. Now a days, these by-products (waste) of the industries are been extensively used in the geopolymer mortar. Geopolymer is inorganic in nature and is typically ceramic. Geopolymer contains an extended range of Alumino-silicates networks held by a covalent bond. Geopolymer is formed by an alkaline solution and a solid Alumino-silicate material. And these by-products (waste) can be the source of silica and alumina in the geopolymer, and after polymerization leads to the production of molecular chains and large networks of units ultimately leading to the strong and hard binder. So the secondary lead slag may also be used in the generation of the geopolymer as it can be a source of silica and alumina. This research investigates the feasibility analysis of secondary lead recycling slag powder in cementitious matrix as a construction material. Three types of secondary lead slag have been investigated in this study. This utilization of lead slag as construction material can help in solving the negative effects of secondary lead slag on environment. The entire study was divided into two parts. In the first part, different mechanical properties of secondary lead slag-based cement mortar specimens with varying percentages (i.e., 0%, 5%, 10%, 15%, 20%, 25%, and 30%) of secondary lead slag have been studied. The results concluded that increase in the replacement of three types on Lead Slag after 5%, the results are not promising as compressive strength decreases rapidly. The strength development is better in Type 1 and 3 based cement mortar specimens as compared to Type 2 Lead Slag based mortar specimens. The strength increases with the age of curing for all types of Lead Slag based cement mortar specimens, as the pozzolana reaction occurs at greater curing age. Type 1 and Type 3 lead slag is highly recommended upto 5% replacement. In the second part, different mechanical properties of secondary lead slag-based geopolymer mortar specimens with varying percentages (i.e., 0%, 10%, 20%, and 30%) of secondary lead slag have been studied. The results concluded that The Lead Slag (Type 1, 2, 3) has good alkaline reactivity. It suggests the possibility of using the lead slag as geopolymer precursor. Type 3 lead slag is highly recommended as it has more Calcium as compared to Fly ash, increasing in hydration process and different hydration products like CASH ad C-S-H are formed in addition to the co-existing geopolymerization product (NaSH).