In the last quarter of 2021, there was a very significant eruption of the Cumbre Vieja volcano on the island of La Palma, belonging to the Canary Islands, Spain. It generated a large amount of pyroclastic volcanic materials, which must be studied for their possible applicability. This work studies the properties and applicability of the lava and volcanic ash generated in this process. The need for reconstruction of the areas of the island that suffered from this environmental catastrophe is considered in this study from the point of view of the valuation of the waste generated. For this purpose, the possibility of using the fine fraction of ashes and lava as a supplementary cement material (SCM) in the manufacture of cement is investigated. The volcanic material showed a chemical composition and atomic structure suitable for replacing clinker in the manufacture of Portland cement. In this study, the cementing and pozzolanic reaction characteristics of unprocessed volcanic materials and those processed by crushing procedures are analysed. To evaluate the cementitious potential by analysing the mechanical behaviour, a comparison with other types of mineral additions (fly ash, silica fume, and limestone filler) commonly used in cement manufacture or previously studied was carried out. The results of this study show that volcanic materials are feasible to be used in the manufacture of cement, with up to a 22% increase in pozzolanicity from 28 to 90 days, showing the high potential as a long-term supplementary cementitious material in cement manufacturing, though it is necessary to carry out crushing processes that improve their pozzolanic behaviour.

Due to a continuously developing population, our consumption of one of the most widely used building materials, concrete, has increased. The production of concrete involves the use of cement whose production is one of the main sources of CO₂ emissions; therefore, a challenge for today’s society is to move towards a circular economy and develop building materials with a reduced environmental footprint. This study evaluates the possibility of using new sustainable supplementary cementitious materials (SCMs) from waste such as recycled concrete aggregates (RCAs) and mixed recycled aggregates (MRAs) from construction and demolition waste, as well as bottom ash from olive biomass (BBA-OL) and eucalyptus biomass ash (BBA-EU) derived from the production of electricity. A micronisation pre-treatment was carried out by mechanical methods to achieve a suitable fineness and increase the SCMs’ specific surface area. Subsequently, an advanced characterisation of the new SCMs was carried out, and the acquired properties of the new cements manufactured with 25% cement substitution in the new SCMs were analysed in terms of pozzolanicity, mechanical behaviour, expansion and setting time tests. The results obtained demonstrate the feasibility of using these materials, which present a composition with potentially reactive hydraulic or pozzolanic elements, as well as the physical properties (fineness and grain size) that are ideal for SCMs. This implies the development of new eco-cements with suitable properties for possible use in the construction industry while reducing CO₂ emissions and the industry’s carbon footprint.

This study’s scope is to collect and analyze all the needed information related to the residential building stocks in Mediterranean countries, especially those that participated in the framework of the HAPPEN project (Greece, Croatia, Cyprus, Italy, Slovenia, Spain, and France). A specific procedure was followed in order to conduct a coordinated evaluation of the residential building stock. The most important variables for a statistical examination of the building stock are outlined, as well as an approach for establishing reference buildings. National data for the seven participating nations were collected and evaluated using the prescribed methodology. The research findings identify six distinct reference buildings in each nation. More specifically, the most representative buildings were distinguished through a cross-country comparison of the obtained data, after classifying the buildings into different classes to which the same approach for deep renovation/refurbishment can be applied.

This study evaluated the viability of biomass bottom ash (BBA) as a supplementary cementitious material (SCM) and sand substitute in cement-based materials. Physical and chemical characterization of BBA from eucalyptus forestry biomass and BBA from olive industry residues was performed. BBA underwent processing through grinding for SCM application and carbonation for sand substitution. Mortar mixtures were prepared with 25% ground BBA replacement for cement and 25% and 50% BBA replacement for sand, both carbonated and non-carbonated. Mechanical behaviour tested through flexure and compressive strength and water absorption at 28 days were assessed. Pulverised BBA enhance compressive strength of mortar compared to a conventional CEM II type cement and Carbonated BBA mortar mixtures improved 28-day compressive strength by 35-55% compared to non-carbonated BBA. BBA from eucalyptus forestry biomass, with pozzolanic activity, exhibited superior strength. The findings support the technical feasibility of BBA in cementitious materials, contingent on adequate processing.

This study evaluates mortars that incorporate mixed recycled aggregates, biomass bottom ash, chamotte, wood waste, and expanded clay as partial substitutes for cement and natural aggregates. Three series of mortars were investigated: with 25% cement replacement, partial sand replacement, and simultaneous replacement of cement and sand. Mechanical, physical, durability, and thermal properties were evaluated, along with their relationships through a correlation analysis. Cement substitution did not result in a drastic reduction in compressive strength and produced limited thermal improvements, whereas sand substitution led to substantially greater reductions in thermal conductivity, ranging from approximately 10.3% for MRA to 59.1% for wood waste compared to the control. Expanded clay reduced thermal conductivity by 24.7%, while BBA-L showed greater insulating potential than BBA-PG but resulted in a reduction in compressive strength. The combination of chamotte, limestone filler as a cement substitute, MRA, and expanded clay as an aggregate substitute provided the best balance between thermal and mechanical performance, achieving a compressive strength of approximately 39 MPa at 90 days and reducing thermal conductivity by nearly 22% compared to the reference mortar. The results demonstrate that thermal performance depends largely on density and porosity, although the optimal selection of materials requires simultaneously considering both mechanical and physical properties.