INVESTIGATING THE USE OF PFA POZZOLAN IN NON-HYDRAULIC LIME MORTAR FOR IMPROVED COMPRESSIVE AND FLEXURAL STRENGTH IN SUSTAINABLE MASONRY CONSTRUCTION

Abstract

Mortar is a vital component in masonry construction, providing the connection between masonry units and enabling them to work as a single material. The choice of mortar significantly affects the flexural and compressive strength of the masonry. Cement-based mortars are widely used in current construction projects, but their production process results in considerable CO2 emissions, leading to severe environmental implications. Lime mortars, with their lower embodied CO2 content, serve as a more sustainable alternative, offering advantages such as increased flexibility, damp resistance, and the capacity to handle more substantial wall movement. The primary disadvantages of lime mortars are their longer setting time and reduced strength compared to cement-based mortars. This paper explores the possibility of incorporating PFA (fly ash) pozzolans into non-hydraulic lime mortar to address these challenges. The findings demonstrate that a minimal 2.5% PFA addition can double the mortar's strength within 28 days, with a maximum strength of over 4 MPa achieved with 5% PFA. As a result, non-hydraulic lime mortars with PFA provide a more sustainable alternative to cement-based mortars, without sacrificing setting time, strength, or overall functionality