A CASE STUDY ON THE VARIATION IN THE QUALITY OF MORTARS USING CDW RECYCLED SANDS

摘要

In order to stimulate the production of recycled aggregates from construction and demolition waste (CDW) in Brazil, research should be carried out on processes capable of providing reasonable standard quality for such materials, without great investment costs, and also to allow an increase in applications of less structural importance, as is the case of masonry and plastering mortars, very traditional in the country. This work presents a case study of the quality of CDW recycled sand for mortars based on the visual classification of the nature of the waste and the control of its fine fraction. Upon watching the production in a recycling plant, in Socorro, Sao Paulo State, for one month 20 CDW samples were collected, with a predominance of red ceramics, which underwent the process of fine fraction removal through washing in a 0.15 mm sieve. Several characterization tests were carried out on the aggregates and on the mortars thus produced. As the visual control technique on the CDW nature is concerned, it can be stated that it was not enough to obtain aggregates considered homogeneous, even though the town chosen is quite small and the building process is predominantly constituted by masonry walls made of bricks from local factories. As for the control of fine aggregate content, it is necessary to find out another way of washing aggregates in order to reduce the range of variation on this property. The results also show that the absorption of the aggregate and its material finer than 75 μm are the main aggregate properties that can cause variability in the mortar properties.