Investigating the durability of reconstituted limestone under acidic environments

Abstract

Local studies have recently highlighted the potential of utilising construction and demolition waste to produce load-bearing building blocks. This innovative approach offers a promising solution for effectively managing the significant waste generated in the local construction sector while promoting environmental sustainability. Building upon previous research conducted in 2013, which extensively examined the durability of reconstituted limestone under salt attack conditions, there is a recognised need to expand upon this investigation by evaluating the durability of reconstituted limestone under acid attack conditions. The following dissertation focuses on analysing the effect of individual acid rain constituents (sulfuric and nitric acid) on the durability of reconstituted limestone. Tests carried out include; (a) Absorption test by immersion. (b) Evaporation test. (c) Cyclic of acid attack. Given the absence of standardised tests for assessing the effects of acid rain on building materials, a test methodology was developed based on this study. All tests were compared with Malta's most common local building stone: the Globigerina limestone. In addition, four samples of lab-produced reconstituted limestone from previous research conducted by Genovese (2013) were also included in the primary cyclic acid attack test for comparison. The results revealed that the reconstituted limestone exhibited higher absorption and evaporation rates than Globigerina limestone. Additionally, both reconstituted limestone samples exhibited a higher weight loss when subjected to cycles of nitric and sulfuric acid attacks, primarily due to the reaction between the acid and cement content found in the reconstituted limestone. This study serves as an initial investigation, laying the foundation for further research on standardising acid attack tests and exploring the production of load-bearing building blocks using construction and demolition waste.