Influence of stabilisers on the unconfined compressive strength of a fine soil

In foundation engineering, weak subgrade soils are usually improved by adding several stabilisers to satisfy construction requirements, but the influence degree of each stabiliser on the strength of the stabilised soils is rarely studied. In this study, a series of unconfined compressive strength tests was conducted on a fine soil stabilised with various proportions of cement, lime, fly ash and gypsum. The influences of the four stabilisers were investigated through quantitative analysis and grey correlation analysis. The quantitative analysis examined the trends of the unconfined compressive strength with increasing contents of different stabilisers. It was found that there existed optimum fly ash and gypsum contents in this study. Also, the cement had the highest positive impact on the unconfined compressive strength. In the grey relational analysis, different normalisation methods were utilised, and it was found that the normalisation method and the trend of the strength with rising stabiliser content affected the order of the impact of various stabilisers. The grey relational analysis with a range-normalisation method provided a reasonable order of impact in this study

An experimental investigation of the impact of specimen preparation and curing conditions on cement-treated material strength (deep mixing method)

In recent decades, the use of Deep Mixing Method (DMM) has developed considerably and its applications are increasing continuously. Although during the past few decades various DMM techniques and methods have been introduced in different projects, there are many changing parameters which make it necessary to evaluate the impact of each condition in any specific project. The present laboratory study has been carried out to determine the impact of mixer type and curing time and conditions on soil stabilised with cement as used in soil mixing methods. Three different types of soil have been used in this research. Unconfined Compression Strength (UCS) and Secant Modulus (E 50 ) were chosen to assess the impact of various parameters on soil improvement in terms of strength. Results after a 28-day curing period indicate that the type of mixing method has a slight impact on the strength of all types of cement-treated soil. It is also concluded that different curing conditions and suction using various salt solutions have a significant impact on the strength of stabilised soil

An experimental investigation of the impact of specimen preparation and curing conditions on cement-treated material strength (deep mixing method)

In recent decades, the use of Deep Mixing Method (DMM) has developed considerably and its applications are increasing continuously. Although during the past few decades various DMM techniques and methods have been introduced in different projects, there are many changing parameters which make it necessary to evaluate the impact of each condition in any specific project. The present laboratory study has been carried out to determine the impact of mixer type and curing time and conditions on soil stabilised with cement as used in soil mixing methods. Three different types of soil have been used in this research. Unconfined Compression Strength (UCS) and Secant Modulus (E 50 ) were chosen to assess the impact of various parameters on soil improvement in terms of strength. Results after a 28-day curing period indicate that the type of mixing method has a slight impact on the strength of all types of cement-treated soil. It is also concluded that different curing conditions and suction using various salt solutions have a significant impact on the strength of stabilised soil

Improvement of Peat Using Portland Cement and Electrokinetic Injection Technique

Peat is often referred as problematic soil due to its high compressibility, low shear strength, and high water content. However, high surface electrical charge and high cationic exchange capacity of peat makes it a good source for transporting and/or exchange with cations. In this study, a series of batch test is performed to find out the effect of strength improvement of portland cement mixed with the peat. Then, the feasibility of injecting cement electrokinetically into peaty soil environment has been assessed. The microstructure of the treated peat was also investigated by scanning electron microscopy and energy-dispersive X-ray spectrometer analysis. The results showed that the undrained shear strength, pH, and water content of treated peat are affected after electrokinetic treatment. Because of the electrokinetic process, the undrained shear strength was improved to maximum of 308 % and minimum of 30 % in the normalized distance of 0.1 and 0.9 from anode, respectively. The pH was also increased to the maximum of 8 in the normalized distance of 0.1 and 0.9 from the anode. However, the water content was reduced after 7 days of electrokinetic processing