Properties of lime-hemp concrete

An area, table and line graph showing information about thermal conductivity

The built environment is responsible for 40% of primary energy use and 36% of energy related CO2 emissions. Therefore, it is important to develop low-energy, carbon-negative, sustainable construction materials to replace existing products. Hemp-lime concrete is a mix of a lime-based binder and hemp that form a carbon-negative, sustainable material of low-embodied energy which can replace traditional, non-sustainable building materials in certain applications. The concrete is light-weight and non-structural, it exhibits a ductile failure and is typically used with a load bearing frame.

This research investigates hemp concrete made with different binders including Portland cement, hydraulic and hydrated limes. It also studies hemp concretes including pozzolans. Most of the pozzolans investigated are waste materials that increase the sustainability of the concrete. The areas investigated span thermal, hygric and mechanical properties. The use of water retainers and accelerators is also investigated.

A clustered column showing the compressive strength on lime at 1 year of untreated composite (bar 1), reference composite (bar 2) and composite subjected to freeze/thaw (bar 3) with results underneath

Hemp concrete is a relatively new material and this project directly contributes to the establishment of testing methods and standards that are currently in progress through the RILEM technical committee on biocomposites for building (TCBBM 51).

Project coordinator: Associate Prof. Sara Pavia
Funded by: Environmental Protection Agency