Effect of Industrial By-Products on Unconfined Compressive Strength of Solidified Organic Marine Clayey Soils

Abstract

The use of industrial by-products as admixture to ASTM Type I cement (ordinary Portland cement (OPC)) was investigated with the objective of improving the solidification of organic marine clayey soils. The industrial by-products considered in this paper were oyster-shell powder (OSP), steelmaking slag dust (SMS) and fuel-gas-desulfurized (FGD) gypsum. The industrial by-products were added to OPC at a ratio of 5% based on dry weight to produce a mixture used to solidify organic marine clayey soils. The dosage ratios of mixtures to organic marine clayey soils were 5, 10 and 15% on a dry weight basis. Unconfined compressive strength (UCS) test after 28 days revealed that the highest strength was obtained with the OPC + SMS 15% mixing ratio. The UCS of specimens treated with this mixture was >500 kPa, compared with 300 kPa for specimens treated with a 15% OPC + OSP mixture and 200 kPa when 15% of OPC was used alone. These results were attributed to the more active hydration and pozzolanic reaction of the OPC + SMS mixture. This hypothesis was verified through X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses, and was confirmed by variations in the calcium carbonate (CaCO3) content of the materials during curing.

Mathematical Models for Stress–Strain Behavior of Nano Magnesia-Cement-Reinforced Seashore Soft Soil

“…In geotechnical engineering, deep mixing method is generally adopted to improve the strength of soil by adding cement to the soil [4][5][6][7][8]. The soft soil is reinforced to impart higher strength through a series of reactions between raw materials and curing agent [9][10][11][12][13][14][15][16]. In addition to the traditional cement curing agent, researchers are constantly looking for some novel materials such as nano materials to improve the bearing capacity of the soft soil layer [2,3,14,15,[17][18][19][20].…”