Use of concrete recycled aggregates as a raw material in lightweight mortar fabrication

Use of concrete recycled aggregates as a raw material in lightweight mortar fabrication

González Cortina, Mariano
Saiz Martínez, P.
Martínez, F.
Viñas Arrebola, C.

2017-06-21

Construction and Demolition Waste (CDW) raises an environmental problem due both to the lack of prevention in their production process and little use of recycled material. In order to improve this situation, over the last years the new legislation on the CDW has entered into force, fostering the recovery of waste at its end-of-life and incorporating a study on CDW management during the planning process and a plan on CDW management during the construction phase. In the development of this research basic materials were used for the cement mortars elaboration in proportion 1:3 and 1:4: cement (CEM II/B-L 32.5 N and CEM IV/B (V) 32.5 N, aggregates (natural aggregates and concrete recycled aggregates) and water. In case of recycled mortars some additive was used. The methodology of the research is divided in two parts: in the first part the most relevant properties of recycled aggregates such as bulk and dry density, absorption, fines content, fineness modulus and friability coefficient were analyzed. In the second part the following tests were carried out: flexural and compressive strength, bond strength, shrinkage, density and water vapour permeability of mortars elaborated with recycled aggregates with the objective to study their feasibility. Because of lower density and higher absorption of recycled aggregates recycled mortars present generally poorer properties compared to traditional mortars. On the other hand, lower density of recycled aggregates presents an advantage in the fabrication of lightweight mortars and thus mortars with lower coefficient of thermal conductivity, what means better thermal behaviour compared to mortars elaborated with natural aggregates. Regarding water vapour permeability, recycled mortars have higher permeability compared to traditional mortars, what enables evacuation of water vapour existing in the interior of a construction avoiding in such a way the condensation in the interior layers of the brick wall. According to the obtained results, recycled mortars develop poorer behaviour compared to traditional mortars. However, these mortars comply with the standards taken as a reference, and their density and water vapour permeability make more attractive the use of these materials in the construction sector.

waste treatment
masonry mortar
recycled aggregate
mechanical properties

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conference paper

(c) 2017 The Author(s)