Development of Lime Based, Load-Bearing Materials for Wall Construction

Abstract

Construction of buildings in the UK is traditionally done using building materials such as concrete blocks, bricks and less so, timber. Although timber is a sustainable product, concrete blocks and bricks require a lot of energy input during fabrication, concrete especially being a large producer of CO2 during its manufacture. Reducing energy consumption either domestically or industrially is an important part of achieving the UK Government’s legally binding commitment to reducing greenhouse gas emissions by at least 80% (relative to 1990 levels) by 2050. New, low embodied energy construction materials are urgently required to enable the construction industry to revolutionize and drastically decrease its carbon footprint. The constituents of the materials investigated were selected based on low embodied energy criterion. To achieve this, lime was selected as the base material with hemp (fibers and shives) and PVAc used as additives. Specially selected nanomaterials were used as fillers. The constituents were combined in a manner, which led to different materials being developed, all exhibiting different characteristics. One characteristic was strength (load bearing) to eliminate the use of timber studding during construction. The results show that the highest strengths were achieved by mixing 10 wt. % hemp fiber, 4 wt. % nanozinc oxide and 12 wt. % PVAc at a 0.4 W/L ratio, yielding 17.7 MPa in compression and 7.3 MPa in flexure.