Earthen construction materials as enabler for circular construction

Abstract

The construction sector in Germany is one of the largest contributor to climate change. The majority of waste generation, resource consumption as well as CO2 emissions relate to the construction and operation of buildings [1][2][3]. In order to tackle such negative impacts, the construction industry has to undergo a major transformation. Circular construction is the most promising answer to close effectively material cycles and to reduce CO2 emissions related to the manufacturing of construction materials. Stakeholders involved in construction have to review the entire life cycle of building products and buildings and develop new approaches that address such shortcomings to turn the linear way of construction into a circular one. Nowadays the strong focus on economic considerations, lacking knowledge as well as unresolved warranty issues amongst others impede this transformation process. To demonstrate the benefits of earthen materials with regards to circular construction, this study analyses the potential of two different internal partition wall systems, based on earthen as well as conventional building materials in a holistic way. Several aspects have been taken into consideration, evaluated through the physical dismantling of both wall systems as well as a LCA assessment. Construction cost as well as other material benefits, such as the hygroscopic performance of construction materials have been investigated as well. The results demonstrate that earthen materials reduce both, construction and demolition waste as well as CO2 emissions and demonstrate a much higher water vapour sorption capacity, a material parameter relevant for the reduction of mechanical ventilations systems. Although the economical assessment shows expectable lower construction cost for the wall system based on conventional materials such figures have to be placed in relation with the other results. In fact, the analysis demonstrates clearly that a holistic approach is needed in order to achieve the necessary shift.