Clay soils are considered as a problematic soil in term of water absorption rate. The ideas of soil improvement method had been widely used to modify the physical and mechanical properties of clay soil. This study aims to identify the optimum percentage mixing of natural fibers in influencing the compaction characteristics. X – ray fluorescent test (X-RF) and Standard Proctor test has been performed to determine the chemical composition of natural fibers and compaction characteristics of soil samples. Natural fibers such as banana, kenaf, and coconut coir were used as a natural soil stabilizer with varying percentage mixing to increase the properties and stability of soil samples. Experimental data obtained from compaction test shows that the appropriate maximum dry density and optimum moisture content for each natural fiber are at 0.5% natural fibers mixing. In this study, the maximum dry density and optimum moisture content for untreated samples are 1650kg/m3 and 7.8%, respectively. Meanwhile, for treated soil samples that mixed with banana, coconut and kenaf fibers are 1760kg/m3 , 1780kg/m3 , 1670kg/m3 and 8.2%, 8%, 11%, respectively. Hence, 0.5% mixing with banana fibers indicated the best possible amount of dry density and moisture content among other natural fibers. Therefore, this study proved that natural fibers can act as a good natural soil stabilizer in increasing stability of clay soil.

The quality of the subgrade is depending on the geotechnical properties, strength and the stabilization technique adopted for problematic soil in order to increase the bearing value. In Malaysia, soft soil is a challenging due to very low strength value and low California Bearing Ratio (CBR) value as well. The soil stabilization process is conducted to increase bearing capacity of marine soil. An experimental works cover from identification of basic soil properties by index test, compaction test and CBR test. Though, the marine soils have to be treated and stabilized with available methods like using natural materials or additive agents. In this study, geotechnical characteristics of marine soil stabilized with CSP content were determined. The unsoaked treated marine soil stabilized with CSP was investigated. Four different compounds of the soil with 2.5, 5, 7.5 and 10% of CSP were mixed and added to determine the unsoaked CBR of the stabilized soil compounds. The results show the inclusion of CSP reduced the plasticity of the soil and highest dry density was decreased with an increase in the optimum water content. Moreover, by increasing the content of CSP the highest CBR value at 2.5 and 5.0 mm penetrations were achieved. The increasing percentage volume of water usage indicates the decreasing value of CBR. The results indicated that CSP contents have potential as a natural stabilizer for applications such as road sub-base material in road construction. The road sub-base will gain great strength with addition of CSP on marine soil

Abstract. Soil compaction plays an important role in every construction activities to reduce risks of any damage. Traditionally, methods of assessing compaction include field tests and invasive penetration tests for compacted areas have great limitations, which caused time-consuming in evaluating large areas. Thus, this study proposed the possibility of using non-invasive surface wave method like Multi-channel Analysis of Surface Wave (MASW) as a useful tool for assessing soil compaction. The aim of this study was to determine the shear wave velocity profiles and field density of compacted soils under varying compaction efforts by using MASW method. Pre and post compaction of MASW survey were conducted at Pauh Campus, UniMAP after applying rolling compaction with variation of passes (2, 6 and 10). Each seismic data was recorded by GEODE seismograph. Sand replacement test was conducted for each survey line to obtain the field density data. All seismic data were processed using SeisImager/SW software. The results show the shear wave velocity profiles increase with the number of passes from 0 to 6 passes, but decrease after 10 passes. This method could attract the interest of geotechnical community, as it can be an alternative tool to the standard test for assessing of soil compaction in the field operation.

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Index properties of soared are the most crucial part of the soil, which impact construction activities due to the rapid growth of urbanization and industrialization. Soft soil is one of the most unstable soil which has a low strength and stiffness index due to its high liquid limit. Stabilization of soil by adding chemical or non-chemical based such as lime and cockle shell powder have proven to improve the index properties of soft soil. Lime and cockle shell powder is the most popular reinforcement materials used in the study on the soil reinforcement for soft soil. The use of lime and cockle shell powder as reinforcement materials in soil are proven effective. The study’s objective is to investigate the effectiveness of different admixtures used in the soil stabilization compared to lime and cockle shell powder on the effect of Atterberg limit and compaction characteristics of soft soil. It is shown the soil reinforcement in soil stabilization is functionally in improving mechanical properties of the soft soil. Meanwhile, the admixture in powder formed to act as a fine binder between soil and stabilizer agents. This will enhance the index properties of original soft soil such as Atterberg limit and compaction characteristics.