Feasibility study on the sustainable utilization of uncalcined clay soils as Low-Cost binders

The need to reduce the negative environmental impact and cost of construction binders have resulted in an imminent need to utilize locally available materials as alternatives. An experimental study was carried out to explore the use of locally sourced raw clay as a binder for construction applications. This approach was implemented to develop a sustainable alternative to Portland cement which is known to be detrimental to the environment and consume a large amount of raw materials. Thus, in this study, clay binders were produced by using various alkali activators and incorporating slag to form a blended alkali activation system. The mechanical and physical characteristics of the developed clay binders were measured at 28 days and the effects of different activators on the physical and mechanical properties of clay binders were assessed. The results of the extensive experimental program indicate that the alkali activation of clay soil and the clay-slag system are feasible options to produce an effective, hardened, and low-cost clay binder. The 28-day compressive strength as high as 30 MPa was achieved with the use of sodium carbonate to activate a clay-slag blend. The sodium silicate and calcium hydroxide solutions showed a positive impact on the strength and durability characteristics of a binder made only with clay soil. However, a clay-slag blended binder activated with sodium silicate, sodium carbonate, and calcium hydroxide solutions showed enhanced strength and durability properties.