WASCON is the reference international conference on the use of alternative materials in construction. It has been held every three years since 1991 and provides a forum for exchange of ideas and current research nationally and internationally on the use of waste, industrial by-products and other recycled materials in construction. An important scientific base for the implementation of alternative materials is given by the numerous contributions to the WASCON conferences.The resource efficiency in construction is a common goal of the international community due to it being the sector that has the highest consumption of materials, simultaneously, is by far the biggest waste generating sector. Therefore, the main objectives of construction industry for sustainable future are to avoid resource depletion of energy, water and raw materials and to prevent environmental degradation caused by facilities and infrastructure throughout their life cycle.In this regard, initiatives such as, “New products from Industrial by-products” and “Closing the loop for construction materials”, are being carried out to promote the transition towards the cirucular economy.