Proof-of-Concept Laboratory-Scale Production of ‘Sand-like’ Material using Clayey Soil

Abstract

Sand is always the ideal infilling material for a land reclamation project due to its ease in placement, can be compacted easily in-situ, high strength and good drainage properties. However, there is a general shortage of sand. Hence, an alternate material that possesses "sand-like properties" is needed. Converting soft clayey soils into material with "sandlike" properties via "sintering" technology can be an alternative. It is a thermal process of converting fine loose particles in the soft clayey soil into a solid and coherent product via mineral and chemical change. A few processes are involved in this "sintering technology" to produce sand-like material. This research focuses on the laboratory-scale study on the effect of various operating conditions of these processes to produce this "sand-like" material. The effect of the high-temperature sintering schedule (e.g. sintering temperature, ramp-up rate, duration of sintering process) on the properties of the sintered clay product was studied. It was found that a controlled raw clay particle size limited to 3 -5 mm, a sintering temperature at 900 °C, and a dwelling duration of more than one hour is needed to produce an almost complete sintered product. The dry loose bulk density of this sintered product is in the range of 1139-1187 kg/m 3 . It was found to have a mean compressive strength of 11 MPa and 3.7 MPa in the longitudinal and transverse direction, respectively, and a friction angle (about 35 -37°) that falls within the category of medium dense sand. Moreover, the permeability of this "sand-like" material was found to be about 1×10 -3 m/s, which is in the range of the gravel-sand mixtures category. The results suggest that the soft soil can be transformed into "sand-like" material by using the proposed sintering technology.