Nowadays, governments all over the world are very worried about environment and consequently about environmental policies; within the actuations assumed, it is given much importance to the reuse, recycling and valorization of wastes, this way decrease the amount of raw materials for the manufacture of new products, the reduction in fuels, the gasses emissions to the atmosphere and of course, the amount of wastes accumulated.
Construction sector has always been considered as disrespectful with the environment; therefore a lot of researchers are trying to change this trend, making an effort for reaching a more sustainable sector using wastes in all the process. One of these wastes that is pretended to introduce in the life cycle of the materials in the construction sector are the construction and demolition wastes (C&DW), that are an important flow in all the world and there are low ratios of recycling.
Actually this kind of wastes has several applications, where is highlighted their use as aggregate in the manufacture of recycled concretes, in roads and highways or as drainage material.
It is intended to give a new application to construction and demolition wastes as pozzolanic addition in cement.
A clay-based waste from a Spanish C&DW management plant was collected. That material consists on 100% of ceramic material (tiles, bricks, etc.)
The incorporation of this kind of wastes in different percentages in substitution of the cement as pozzolanic addition has produced good results, with the final achievement of one patent (ES2512065).
The object of the current research work is the study of the durability of these new blended cements based on construction and demolition waste as pozzolanic addition, focusing on the sea-water attack, being possible the comparison with cements where this kind of materials has not been used.
The durability is going to be studied in cement pastes, in two different samples, the first one, an ordinary Portland cement (CEM I 42.5R) and the other sample, a blended cement with a 30% addition of C&DW.
The evolution of mechanical behavior and morphology were evaluated in both samples. This way is possible the comparison the properties of cements with and without active addition.
The substitution of the cement by C&DW as pozzolanic addition (considering the waste as secondary raw material), improves the durability of cements in comparison to plain cements and produces the improvement in environmental quality, in keeping with the current European Union Horizon 2020 guidelines, informed by the principles of the circular economy.
Acknowledgements
Thanks to the different Spanish Ministries for the grant awarded for the consecution of three research projects (BIA2013-48876-C03-IR, BIA2013-48876-C3-2 and BIA2016-76643-C3-1-R) that have led the results shown.
