Boron-Containing Waste Utilization in Soil Improvement Applications and Their Incorporation as Additives to Cement: A Case Study on Samples from Türkiye’s Boron Deposits

This study’s primary objective is to determine how boron-containing wastes from the stripping areas of the Emet–Bigadiç (Türkiye) boron deposits affect the mechanical performance of cement-based mortars and the effectiveness of weak soil improvement. The Bigadiç samples contain colemanite, calcite, dolomite, and quartz minerals, whereas the Emet samples predominantly comprise calcite. The wastes were incorporated into the cement matrix in two different forms: (i) solid-phase cement replacement and (ii) boron waste solution additive. Experimental findings demonstrated that replacing 10% of cement with a 4% Bigadiç-origin boron waste solution resulted in a compressive strength of 55.37 MPa after 7 days of curing, which is higher than that of the reference mixture. Also, the study revealed that the addition of 15% boron waste to weak soils increased the soil density to 1728 kg/m3 by filling micro-voids and enhancing intergranular interlocking. Due to this physical filling and chemical bridging effect, CBR value increased from an initial 4 to 6, providing a significant improvement in the soil’s deformation modulus and bearing capacity. Consequently, used boron wastes not only provide high mechanical performance in cement-based systems but also offer potential as an alternative additive material for sustainable and cost-effective soil stabilization applications.