Assessing the effect of seawater and magnesium sulfate on the durability and strength properties of cement-stabilized full-scale soilcrete column constructed in clayey soil

Abstract

Jet grouting techniques have lately become one of the soil enhancement technologies used to increase the strength of poor soils and resolve most of their difficulties. Seven full-scale soilcrete columns (SC) were formed in clayey soil using a one-to-one water-to-cement ratio and different parameters, including five different pressures (30, 32.5, 35, 37.5, and 40 MPa) and three different rotating rates (25, 35, 45 rpm). These metrics were used to assess SC's resistance to chemical attacks [seawater, magnesium sulfate (MgSO4)]. Additionally, it is also working on the strength investigation (unconfined compression test) of samples after 105 days of curing in chemical solutions. Scanning electron microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX) were used to study the microstructural behavior and chemical element distribution of full-scale SCs. As a result, chemical attacks significantly affected upon the SC samples regarding pressure injection and jet grout's rotation parameters. In detail, the seawater solution positively impacted on the strength characteristic of SC specimens compared with the normal environment, which is the average strength has been increased 20%. While, considerable deterioration and deformation were detected in MgSO4 solution, leading to losing the mass and decreasing the strength for both parameters, ranging between -10.2% and -58.8% for mass change and 2.0 and 9.5 MPa for strength, at 105 days curing. SEM and EDX images proved the chemical attacked deteriorations and generation of hydration product with pozzolanic reactions.