Experimental investigation of parameters influencing mechanical properties of hemp concretes using design of experiment method

Abstract

Global concerns about climate change have led to the development of building materials that use plant biomass with the added benefit of sequestering carbon from the atmosphere. Lightweight concrete made with hemp, is a material with huge potential in terms of its ability to achieve hygro-thermal performances close to those of polystyrene. This ecological material, referred to in the literature as hemp concrete, is made of some components that, depending on the chosen combination, can generate different results of the physic-mechanical properties. The method is based on a series of experiments that are generated using a program called Design of Experiments (DoE). This program uses statistical analysis of a series of experiments performed by varying one of the input parameters, like the amount of hydrated lime or cement. Following this analysis, it is possible to identify those elements used in the composition, which produced a significant influence on the physical-mechanical properties of hemp concrete. Moreover, this method also allows a quantification of the influences so that the parameters can be ranked, with a minimum number of experiments. The method is, in the same time, a modern and an economical technique used for experimental planning. The aim of the research is to quantify numerically the influence of each component element of the mixture that determines variations of the physical-mechanical properties in hemp concrete. This study will contribute in the future to the optimization of compositions, which will be differentiated on the basis of mechanical performance or thermal insulation criteria.