Recovery of Excavated Materials as an Alternative Solution to Earth Building Materials

Abstract

The tunnel excavation works generate huge quantities of earth. These excavated materials are primarily stored in landfills. This paper proposes an alternative solution for valorizing excavated earth in earthen constructions. Firstly, the excavated earth was characterized using differential and gravimetric thermal analysis (DTA / TGA), infrared spectra (FTIR), and X-ray diffraction. Hence, sand, fine particles, and water extracted from excavated earth are used to elaborate mortars’ stabilized with cement, lime, and slag. Short hemp fibers were also used to diminish shrinkage cracks. The quantity of stabilizers was fixed to 5% by weight of the excavated earth while the water/solid ratio was maintained constant and equal to 0.45. Five different mortar formulations were performed using excavated earth and were cured for 28 days in a controlled environment before testing. Compressive and three-point flexural tests were carried out to determine specimens’ mechanical properties. The characterization results show that the excavated earth are mainly composed of dolomite, calcite, quartz, and clay. While, the mechanical results show that the stabilized excavated earth with cement additive presents higher mechanical properties relative to the other additives.