Cement matrix containing lightweight aggregate based on Non-Metallic Fraction Printed Circuit Boards (NMFPCB'S)

Abstract

Materials such as river sand, used in construction, have a high demand, and thus generate great environmental impacts while being extracted, such as erosion of the rivers banks and your siltation. With the increasing restriction of river sand extraction which can generate a reduction in the product's offer in the civil construction sector, it is necessary to develop waste recycling technologies for the production of sands with less environmental impact. One of the alternatives for the production of mortar for construction is the replacement of sands extracted from rivers by waste from other industries, such as the electronics industry that presents large and growing production worldwide, due to technological advances. Thus, this work aims to evaluate the influence of partial replacement of quartz sand by lightweight aggregate based non-metallic fraction of printed circuit boards (NMFPCB's) on the properties of cementitious matrix in the fresh and hardened states. For this, the electronic components of the printed circuit boards (PCBs) were removed, they were grinded and then through magnetic and electrostatic separation processes to separate the most valuable and abundant part of metals. The water to cement ratio was 0.48 in all the experiments, the Portland cement to sand ratio was 1:3 (in mass) for the control, and the mortars with NMFPCB's replacement of sand by volume of 25% and 50% were also made. These were characterized mechanically by axial compressive strength test at different ages. The partial results showed that with the increase of sand substitution by NMFPCB's there was a reduction of the mortar consistency index in the fresh state. Results showed that matrix that suffered the substitution of sand by light aggregate, decreased the compressive strength in relation to the reference, but have potential to use in construction industry as blocks or non-structural elements.