Evaluation of Belgian clays for manufacturing compressed earth blocks

1. Introduction Faced with the current environmental challenges about climate change and depletion of earth’s resources (UNEP/UNECE, 2016), the building sector needs to renovate its design practices and methods by taking into account economic, sanitary and comfort criteria. The development of materials that address these criteria and promotion of their use is put forward. Raw earth is one of these materials (Niroumand et al., 2017). Raw earth designates the earth used in construction unfired but simply dried. Earth construction techniques are very varied: adobe (the molded and sun dried brick), cob (construction made by stacking earth balls handmade), wattle and daub (the earth used in filling load-bearing structures, usually made of wood), rammed earth (earth compacted in a framework), and Compressed Earth Block (compacted earth, achieved using manual or mechanical presses) are the main ones (CRAterre et al. 1979; Houben & Guillaud, 1989). Raw earths can be used to produce compressed earth blocks (CEB) with ecological, thermal and economic advantages. However, the raw earth blocks have the disadvantage of deteriorating to humidity change or abrasion. This decreases its durability, i.e. resistance over time (Rigassi, 1995). Stabilization is a process to improve the impermeability (water resistance) and the hardness (impact and friction resistance, reduction of crumbling) of the earth block. There are more than a hundred products stabilizing the earth: sand, gravel, cement, l