Papers by Keyword: Expansive Soil

Abstract: Expansive soil is strongly influenced by the water content inside the soil particle , the significant changes of moisture content cause volume changes. The swelling and shrinkage potential of the soil can be indirectly identified by running the consistency limits test which are by controlling the plasticity index (IP) value and shrinkage limit (SL) value. This research aims to determine the value of liquid limit (LL), plastic limit (PL), plasticity index (IP), and shrinkage limit (SL) of soil-bentonite mixtures as expansive soil materials and analyzing the expansion potential of the modificated materials by its value. There were 5 variations of mixtures which are original soil (S), bentonite (B), 25%S+75%B, 50%S+50%B and 75%S+25%B. The results show the properties of soil-bentonite mixtures. The specific gravity and the grain size distributions were not significantly affected by the increase of the amount of bentonite. LL,PL and PI value significantly increase while SL value were decreased. Along with the increase of bentonite percentage, the activity value also increased by 1.5 to 4. It summarizes that by adding bentonite on the original soil, the expansion potential of the soil mixtures also increased.

Abstract: Our research aims to address the challenges posed by expansive soils, which can swell upon absorbing water and shrink upon drying, posing a threat to structures. Stabilization of such soils is crucial for any construction project, often requiring physical or chemical methods. In this study, tile powder, sourced from a tile manufacturing industry, is utilized as a chemical admixture due to its high lime content, which aids in reducing the swelling nature of expansive soil. Soil samples from three distinct locations were collected and subjected to testing to determine their index properties. Among the samples, the soil exhibiting significant swelling characteristics was selected for further analysis. This soil was treated with varying percentages of tile powder (4%, 8%, 12%, 16%, and 20%), and the associated index properties were evaluated. The results indicated a decrease in soil swelling, Atterberg limits, and specific gravity, while the strengths obtained from compaction and unconfined compressive strength tests showed improvement with higher concentrations of tile powder. Notably, 20% percentage of tile powder revealed the most substantial enhancement in soil strength. This study underscores the potential of tile powder as an effective stabilizer for expansive soils, offering a sustainable solution for efficiently utilizing waste materials in construction projects.

Abstract: An experimental study was undertaken to investigate the effect of plastic and granite waste powder on the geotechnical performance of expansive soil, using different mix ratios. The soil studied is Hachem, in the northwestof Algeria. In this context, first reinforcing the plastic powder with granite powder, then add the mixture to the expansive soil. The percentage of plastic powder is (0%, 1%, 2%, 3%, 4%) and reinforced at 2%, 4%, 6% and 8% with granite powder. The experimental results showed a gradual decrease in liquid limits, swell potentials, and swelling pressure as the proportions of plastic and granite powder increase. In terms of the results obtained by reducing swelling and swelling pressure values and increasing unconfined compressive strength (UCS) tests and ductility values, this mixture of waste plastics and granite can be of great importance in improving the mechanical properties of samples.

Abstract: Expansive soils are known to show significant volumetric changes in response to changes in the moisture content. Such soils swell when the moisture content is increased and shrink when the moisture content is decreased, thereby causing distress and damages to structures founded on them. Construction developments on naturally occurring expansive soils are usually problematic. This study examines the properties of expansive soil obtained from the city of Muscat in Oman. The expansive soil samples were further treated with gypsum, which was obtained from waste plasterboards, at varying quantities of 3%, 6%, 9% and 12% by mass in an attempt to stabilize the soil. Based on USCS classification system, the expansive soil was identified a poorly clay with high plasticity (CH) with AASHTO classification of A-6. The pH test confirms the reaction between expansive and gypsum, while both the compaction and unconfined compression strength (UCS) tests revealed the optimum percentage of gypsum required to enhance the properties of expansive soil to be 9% by mass. The unconfined compression strength (UCS) test yielded a 37.7% increase over that of untreated expansive soil at 28 days of curing. The California Bearing Ratio (CBR) test of the treated soil yielded a 57% increase in CBR value for expansive soil treated with 9% of waste gypsum over untreated expansive at the unsoaked state and 70% at soaked state. Overall, a solid understanding of the physical and engineering properties of expansive soil, and the confirmation of the potential use of gypsum for its stabilization, was achieved in this study.

Abstract: The interest in expansive soils goes as far as they were considered as a new phase of soil mechanics. Problems associated with potential volume change of soils occur worldwide, mainly in the arid and semi-arid climatic region, as is the case of the country of this research. These problems are particularly existed in regions where the variation in the moisture content can cause a potential expansiveness of the soil. In fact, Bentonite/Sand mixture represents one of the available answers for the geotechnical engineering problems such as heaves, cracks and other damages caused by swelling and shrinkage. This mixture may be used to 1) reduce the settlement time of structures, and 2) increase the permeability of soils. The main target of the present work is to demonstrate the influence of adding sand on an expansive soil (bentonite) behavior. This includes an investigation to the effect of the amount and the particles size of sand on the physical properties of the expansive soil. The reduction in swelling and swelling pressure of the expansive soil by the addition of different percentages and different particles size of sand and the consequent effect on strength characteristic were also studied. Thirteen samples of Bentonite/sand mixture were used in this study to evaluate the effect of the sand percentages on the swelling behavior. To implement the laboratory program, many tests were used which were sieve analysis, Atterberg’s limits, compaction, and free swelling test with swelling pressure test. The results indicated a reduction in the liquid limit of around 55% and in the plastic limit of around 54%, where the increase in the maximum dry density was 46%. On the other hand, the reduction in the swelling pressure was 87.5%.

Abstract: The hydroxy-aluminum solution is prepared by alkali neutralization titration and the subsequent cross-linking tests are designed by mixing the hydroxy-aluminum solution and expansive soil, followed by the discussion on the influence of the molar ratio of OH^- to Al³⁺ and ratio of total aluminum to expansive soil on the swelling behavior of the cross-linked soil. The free swelling ratio of the cross-linked soil decreased significantly, indicating that the main aluminum species that changes the expansion properties of the cross-linked soil is [Al₁₃]⁷⁺.

Abstract: Many road and highway have been constructed over the expansive soil in Java island without proper soil improvement for the subgrade. The behavior of the column on the expansive soil needs for study numerically and large scale. In this study, a numerical analysis is performed to study the effect of swelling on the deformation of the soil stabilized column supported flexible pavement. The main focus of the research is to obtain the deformation due to swelling and vehicle loading. The methodology including comparison the differential settlement of the soil stabilized column supported flexible pavement and unsupported flexible pavement as control model. The numerical analysis was modeled using finite element method. The simulations result that the column installation to support flexible pavement reduced the heaving and differential settlement of the pavement effectively. In case the overlay was performed for rehabilitation and maintenance of the pavement, the mini-columns can be installed before the overlay works. However, the conclusions of the study were limited to the result of numerical modeling that depended on the applied material model and volumetric swelling.

Abstract: Expansive soil of Nanyang Province in this experiment was as the research object and the different lime-mixed rates and basalt fiber-mixed rates on the strength characteristics of expansive soil were studied. The test results show that the maximum dry density and plasticity index of reinforced expansive soil were decreased along with the increased lime-mixed rates and the optimum water content was increased in the wake of the increased lime-mixed rates under the same compaction effort; unconfined compressive strength would be a peak along with the increased lime-mixed rates, ductility of reinforced expansive soil was enhanced by the basalt fiber; expansibility of reinforced expansive soil was slashed by lime and basalt fiber which was the dominant factor.

Abstract: In view of the holes appearing in different areas of geo-membrane when the geo-membrane technology is applied to the unsaturated expansive soil canal slope, the VADOSE/W is used to analyze the pore-water pressure of the internal canal slope by changing the falling water level. The results show that the hole is nearer to the toe of slope, its effect on the whole seepage field is greater. The greater the rate is, the soil water content is greater.

Abstract: In view of the holes appearing in different area of geo-membrane when the geo-membrane technology is applied to the unsaturated expansive soil slope, the VADOSE/W is used to analyze the wetting-drying cycles caused by rainfall and evaporation on slopes covered by geo-membrane. The influence on the pore-water pressure and volume water content were discussed just caused by the holes. The results show that the hole is nearer to the toe of slope, its impact on the whole seepage field is greater. In addition, the hole appears on the top of slope that the wetting-drying cycle effect is remarkable. It is ensured that the integrity of the geo-membrane which in the lower slope and take some drainage measures in the construction process.