Mechanical, physical and durability properties of activated alkali cement based on blast furnace slag as a function of %Na2O

Abstract

The use of activated alkali cements (AAC) as a replacement for Ordinary Portland cement (OPC) has become a viable alternative. This is due to the advantages of these materials, such as the possibility of using wastes or industrial by-products in their composition, contributing to environmental sustainability, in addition to the mechanical properties’ superior to OPC. The objective of this work was to evaluate the mechanical, physical and durability properties of an AAC based on blast furnace slag. The production of specimens was carried out in the proportion 1:2:0.45 (binder: aggregate: water), varying the sodium content in the alkaline solution between 2.5% and 15% and varying the age of thermal cure at 65ºC in 7 and 28 days. Compressive strength tests, calorimetry, diametrical compressive strength, density, electrical resistivity, capillary water absorption, water absorption and determination of porosity were carried out. It was observed that the compressive strength values for the 10% sodium composition were 22.12 MPa at 7 days and 41.07 MPa at 28 days. OPC, on the other hand, showed strength of 7.85 and 16.25 MPa, at 7 and 28 days in thermal cure at 65ºC, respectively. In addition, the performance of activated alkali cement-based mortar was superior to cement-based mortar in the other parameters evaluated. Thus, it is concluded that the use of blast furnace slag is a viable alternative for the production of AAC, a potential substitute for OPC, a material whose production is extremely polluting.