Soil cement is a construction material with significant potential for widespread application in water resource management, particularly in providing overtopping protection for levees. However, the requirement for base soil to have a specific particle composition-predominantly coarse particles with minimal fine particles-limits its broader practical use. This study focuses on clarifying the erosion resistance of soil-cement material manufactured from clayey silt (ML) soil, a type of soil that does not meet the Portland Cement Association's requirements for mixing with fly ash and cement. Hydraulic model experiments were conducted to assess the erosion resistance of this soil-cement material under overflow conditions. Remarkably, the results showed high erosion resistance, withstanding flow velocities exceeding 6.15 m/s with minimal erosion damage. This level of performance suggests that the ML soil-fly ash-cement solution is well-suited for protecting levees up to 4 m in height during overtopping events. Specifically, for levees with a height of 3 m and slope coefficients of m = 2 and m = 3, the permissible overflow depths are 0.4 m and 0.5 m, respectively. For 4 m-high levees with the same slope coefficients, the permissible overflow depths are 0.3 m and 0.4 m, respectively. Elucidating the erosion resistance of soil cement made from ML soil is expected to promote the application of this material for levee protection during overtopping scenarios.

In this paper, the experimental findings on the use of Limestone Calcined Clay Cement (LC3) in the stabilization of sub-grade expansive soils are reported. The effect of LC3 on mechanical properties of subgrade soil was investigated experimentally through the soaked California Bearing Ratio (CBR), Proctor and Atterberg limits tests. The difference in the performance between LC3 and Ordinary Portland Cement (OPC) treated subgrade soils was studied for comparison purposes. The LC3 and OPC stabilizers were separately mixed with the soil in the proportions of 1%, 1.5% and 2% by dry weight of the soil. The results showed that the addition of both LC3 and OPC increased plastic limit, reduced plastic index, liquid limit and linear shrinkage of the treated soils. The Maximum Dry Density (MDD) of the soil was observed to increase with a corresponding decrease in Optimum Moisture Content (OMC) upon adding varying cement dosages. Additionally, the soaked CBR of the treated soil was observed to increase significantly with increasing cement content. The maximum CBR and MDD improvement were observed at 2% cement dosage, while OMC was reduced, hence, it could be regarded as the optimum dosage for soil stabilization. The performance between LC3 and OPC treated subgrade was quite comparable. In conclusion, LC3 was found to improve the strength and stability of subgrade soil.

Ferronickel slag is the solid waste slag produced by smelting nickel-iron alloy. After grinding ferronickel slag into powder, it has potential chemical activity. It can partially replace cement and reduce the amount of cement, and is conducive to environmental protection. The mechanical properties of soil cement were investigated through the compressive strength test and inter-split tensile test of ferronickel slag powder soil cement with different dosages. To further study the mechanism of ferronickel slag powder's action on soil cement microscopically, the microstructure of soil cement was analyzed by using a scanning electron microscope and nuclear magnetic resonance equipment. The results of the study show that the incorporation of ferronickel slag powder can enhance the compressive and tensile strength of soil cement. The best performance enhancement of ferronickel slag powder was achieved when it was doped with 45% of its mass. The hydration products of soil cement increased with the increase in the doping amount, but the excessive doping of ferronickel slag powder would lead to a weakening of the hydration reaction and a decrease in the strength of the soil cement. At the same time, ferronickel slag powder plays the role of filling the void of soil cement. With the increase in ferronickel slag powder, the large pores inside the soil cement are reduced and the structure is denser.

Adding fibers into cement to form fiber-reinforced soil cement material can effectively enhance its physical and mechanical properties. In order to investigate the effect of fiber type and dosage on the strength of fiber-reinforced soil cement, polypropylene fibers (PPFs), polyvinyl alcohol fibers (PVAFs), and glass fibers (GFs) were blended according to the mass fraction of the mixture of cement and dry soil (0.5%, 1%, 1.5%, and 2%). Unconfined compressive strength tests, split tensile strength tests, scanning electron microscopy (SEM) tests, and mercury intrusion porosimetry (MIP) pore structure analysis tests were conducted. The results indicated that the unconfined compressive strength of the three types of fiber-reinforced soil cement peaked at a fiber dosage of 0.5%, registering 26.72 MPa, 27.49 MPa, and 27.67 MPa, respectively. The split tensile strength of all three fiber-reinforced soil cement variants reached their maximum at a 1.5% fiber dosage, recording 2.29 MPa, 2.34 MPa, and 2.27 MPa, respectively. The predominant pore sizes in all three fiber-reinforced soil cement specimens ranged from 10 nm to 100 nm. Furthermore, analysis from the perspective of energy evolution revealed that a moderate fiber dosage can minimize energy loss. This paper demonstrates that the unconfined compressive strength test, split tensile strength test, scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) pore structure analysis offer theoretical underpinnings for the utilization of fiber-reinforced soil cement in helical pile core stiffening and broader engineering applications.

Searching for alternative material options to reduce the extraction of natural resources is essential for promoting a more sustainable world. This is especially relevant in construction and infrastructure projects, where significant volumes of materials are used. This paper aims to introduce three alternative materials, crushed ground glass (GG), recycled gypsum (GY) and crushed lime waste (CLW), byproducts of construction industry geomaterials, to enhance the mechanical properties of clay soil in Cartagena de Indias, Colombia. These materials show promise as cementitious and frictional agents, combined with soil and cement. Rigorous testing, including tests on unconfined compressive strength (qu) and initial stiffness (Go) and with a scanning electron microscope (SEM), reveals a correlation between strength, stiffness and the novel porosity/binder index (eta/Civ) and provides mixed design equations for the novel geomaterials. Micro-level analyses show the formation of hydrated calcium silicates and complex interactions among the waste materials, cement and clay. These new geomaterials offer an eco-friendly alternative to traditional cementation, contributing to geotechnical solutions in vulnerable tropical regions.