Hygrothermal properties of soil–cement construction materials

Envelopes play important functions to regulate hygrothermal conditions in buildings that help in achieving an efficient, comfortable and healthy indoor environment. Alternative materials, as cement-stabilized earth blocks (CSEB), give new opportunities to make friendly environmental envelopes. Earth materials to make soil–cement masonry are easy to obtain, abundant in nature, and their use minimizes environmental impacts and improves thermal performance of bricks. Soil-cement mixtures with low amount of sand are actually discarded in construction industry. Moisture and cement content should be optimized for each soil type to produce CSEB. The objective of this work is to evaluate the influence of moisture and cement content in compacted loess soil–cement mixtures used in construction masonry. Thermal conductivity and specific heat were experimentally determined, and from them, diffusivity and effusivity were computed for each mixing ratio. Numerical models were developed, by using the finite element method, to analyze the experimental results. The results show that compacted silt with a very low sand fraction and cement content between 3% and 9 % has low thermal conductivity and low capacity to exchange heat with the environment when moisture content is low enough.