Elastic modulus and stress-strain curve analysis of a tungsten mine waste alkali-activated concrete

Abstract

In the paper the compressive strength, the elastic modulus and the stress-strain curve of an alkaliactivated concrete were studied. A tungsten mine waste mud (TMWM), aggregate (also from the tungsten mine), glass waste and metakaolin were used as raw materials. Sodium silicate and sodium hydroxide were used as activators. First, TMWM chemical composition was determined by scanning electron microscopyenergy dispersive spectroscopy (SEM-EDS). The maximum particle size was 18mm. Two cubes with side dimension of 15cm were prepared from the mixture. Samples were cured at 60°C for 24 hours. A concrete mixer, vibration table and an oven were used in the process. After the curing process, cubes were cut into seven prisms and one cube with the dimensions 15x7.4x7.4cm and 7.4cm respectively. After 28 days, the laboratory tests were performed. During the compressive strength tests, the displacements were also recorded which allowed drawing the stress-strain curve of the samples. The compressive strength ranged from 17.27 to 28.84MPa. The elastic modulus was calculated by four different standards: ASTM, LNEC and European standard. The elastic modulus ranged from 2.48 to 7.49GPa what showed that the material is more elastic than ordinary Portland cement concrete.