Increase In Maximum Dry Density Research Articles

Use of Paper Ash and Lime as a Sustainable Stabilized Materials for Lateritic Soil

This research investigates the effectiveness of paper ash and lime for stabilizing lateritic soils in road construction applications. We assessed varying concentrations of paper ash and lime (0%, 3%, 6%, and 9%) to evaluate their effectiveness for soil stabilization. Initial analyses, including grain size distribution through wet sieving, specific gravity, moisture content, and Atterberg limits, were conducted to classify the soil. Following this, strength and compaction tests utilized standard proctor compactive energy, a method well-suited for field application. The findings indicated a general reduction in Atterberg limits (liquid limit, plastic limit, and plasticity index), an increase in maximum dry density (MDD), and a decrease in optimum moisture content (OMC) with increased concentrations of paper ash and lime. A thorough analysis of the results, along with a comparison to established standards, demonstrated significant improvements in soil properties. Specifically, the study found that 6% paper ash provided optimal stabilization, while 9% lime was effective as a stabilizing agent. These materials are suitable for use in the construction of subgrades and subbases for roads, aligning with AASHTO standards.

Physical and Mechanical Properties of All-Solid-Waste-Based Binder-Modified Abandoned Marine Soft Soil

Large quantities of abandoned marine soft soil are generated from coastal engineering which cannot be directly utilized for construction without modification. The utilization of traditional binders to modify abandoned marine soft soil yields materials with favorable mechanical properties and cost efficiency. However, the production of traditional binders like cement leads to environmental pollution. This study uses a CGF all-solid-waste binder (abbreviated as CGF) composed of industrial solid waste materials such as calcium carbide residue (CCR), ground granulated blast furnace slag (GGBS), and fly ash (FA), developed by our research team, for the modification of abandoned marine soft soil (referred to as modified soil). It is noteworthy that the marine soft soil utilized in this study was obtained from the coastal area of Jiaozhou Bay, Qingdao, China. Physical property tests, compaction tests, and unconfined compressive strength (UCS) tests were conducted on the modified soil. The investigation analyzed the effects of binder content, compaction delay time, and curing time on the physical, compaction, and mechanical properties of CGF-modified soil and cement-modified soil. Additionally, microscopic experimental results were integrated to elucidate the mechanical improvement mechanisms of CGF on abandoned marine soft soil. The results show that after modification with binders, the water content of abandoned marine soft soil significantly decreases due to both physical mixing and chemical reactions. With an increase in compaction delay time, the impact of chemical reactions on reducing water content gradually surpasses that of physical mixing, and the plasticity of the modified soil notably modifies. The addition of binders results in an increase in the optimum moisture content and a decrease in the maximum dry density of CGF-modified soil, while the optimum moisture content decreases and the maximum dry density increases for cement-modified soil. Moreover, with an increase in binder content, the compaction curve of CGF-modified soil gradually shifts downward and to the right, while for cement-modified soil, it shifts upward and to the left. Additionally, the maximum dry density of both CGF-modified and cement-modified soils shows a declining trend with the increase in compaction delay time, while the optimum moisture content of CGF-modified soil increases and that of cement-modified soil exhibits a slight decrease. The strength of compacted modified soil is determined by the initial moisture ratio, binder content, compaction delay time, and curing time. The process of CGF modification of marine soft soil in Jiaozhou Bay can be delineated into stages of modified soil formation, formation of compacted modified soil, and curing of compacted modified soil. The modification mechanisms primarily involve the alkali excitation reaction of CGF itself, pozzolanic reaction, ion-exchange reaction, and carbonization reaction. Through quantitative calculations, the carbon footprint and unit strength cost of CGF are both significantly lower than those of cement.

Effect of rice husk ash on soil stabilization at Dinajpur City

Understanding local conditions is crucial for applying soil stabilization principles from other regions to a specific country for effective and sustainable stabilization methods. This investigative study delves into the suitability of locally available Rice Husk Ash (RHA) for incorporation into local building construction practices at Dinajpur, Bangladesh, aiming to minimize the volume of waste disposed of in the environment, thereby mitigating environmental pollution. Conventional soil stabilization techniques are becoming increasingly expensive due to the rising costs of stabilizing agents such as cement. Replacing a portion of the stabilizing agent with RHA could potentially reduce the cost of stabilization while also minimizing environmental harm. RHA comprises 85-90% silica, making it an excellent substitute for silica in soil stabilization. Silica is recognized as an effective binding agent alongside cement. The soil sample selected for this research is a highly plastic clay (CH), which necessitates significant strength enhancement. Three soil samples were stabilized with varying percentages of RHA and a minimal amount of cement. Observations were made to assess the changes in soil properties, including Maximum Dry Density (MDD), Optimum Moisture Content (OMC), and Unconfined Compressive Strength (UCS). The results obtained indicate that increasing RHA content leads to an increase in MDD but a decrease in OMC. Additionally, the UCS of the soil exhibits substantial improvement to up to 88% with increasing RHA content up to 10%. Based on the observed maximum strength enhancement, a 10% RHA content combined with 6% cement is recommended as the optimal combination for practical applications.

Characterization of black cotton soil by using granulated blast furnace slags

Soil stabilization is the best way to enhance the characteristics of low-quality soil. The properties may include, permeability, compressibility, strength, durability, etc. It is required when there is a need for construction on the poor sub-soils that are not suitable for that particular construction. Black cotton soil (BC) has a high clay content and is also considered as compressible soil with shrinkage and swelling characteristics and a constrained bearing capacity. It expands during the rainy season due to water absorption and contracts during the summer, which gives rise to serious structural deterioration. This study targets to stabilize this black cotton soil using ground granulated blast furnace slags (GGBS). It is a by-product of iron found in the blast furnace. It is extremely cementitious and contains a large amount of calcium silicate hydrates that increase its durability, strength, and appearance. In this study, GGBS is used at different percentages such as 5 %, 10 %, 15 %, 20 % and 25 %. Sodium hydroxide is also added in various dosages from 0.5 M, 1 M, 2 M, 4 M and 6 M. The major goal of this study is to investigate how GGBS affects the engineering parameters such as Atterberg’s limit, differential free swell (DFS), Compaction characteristics (i.e., maximum dry density (MDD) and optimum moisture content (OMC)) and unconfined compressive strength (UCS). The durability characteristics of soil-GGBS mixtures are also studied. Results show that as compared to virgin soil, adding 25 % of GGBS to BC soil resulted in an increase in MDD of around 16.5 % and a decrease in OMC of about 29 %. Further, it is also found that compared to (Soil + 20 % GGBS), the UCS value of the (Soil + 20 % GGBS + 4 M NaOH) mixture increased by roughly 36.5 %. Finally, the optimum concentration of GGBS content is found as 20 % while treated with 4 M NaOH solution.

The Effectiveness of Residual Soil, Orashi River Sand, and Sombrero River Sand as Stabilizing Agents for Subgrade Soil of Highway Pavement

The study investigated the effect of different stabilization materials, including residual soil and river sands, on the properties of subgrade soil for road and pavement structures. The results showed that the chemical composition of the subgrade soil was dominated by calcium, aluminum, and silicon, indicating a mineral clay soil. The use of stabilization materials led to a decrease in fines content and an increase in maximum dry density. The behavior of optimum moisture content was non-linear, and the liquid limit of the stabilized subgrade soil decreased significantly for all three materials, indicating a decrease in soil swelling ability. The study also revealed that the use of composite materials of cement and residual soil or river sand can improve the properties of subgrade soil and lead to an increase in unconfined compressive strength. The findings of this study can aid in the selection of appropriate stabilization materials and methods, and in the optimization of the use of these materials in road construction for improved strength and durability. Further research is needed to fully understand the characteristics of subgrade soil and determine the most effective methods for its stabilization and management. This study investigates the effects of residual soil and river sands on the mechanical properties of subgrade soil, with a focus on liquid limit, plastic limit, plasticity index, and unconfined compressive strength. The results suggest that residual soil, Orashi River sand, and Sombrero River sand are effective stabilizing agents for subgrade soil, with an increase in strength observed with increasing percentages of stabilizing material. However, there is an optimum content of stabilization material required to achieve maximum strength values, beyond which the strength decreases. The study also highlights the importance of considering the effect of soaking on the strength of subgrade soil and demonstrates the effectiveness of using composite .........

Influence of Waste Marble Dust on the Improvement of Expansive Clay Soils

The marble process industry from Shaq Al‐Thouban region, which is located in East Cairo, Egypt, produces a huge amount of marble wastes every day during the cutting and processing stages. Up to now, most of these wastes are dumping on open land which creates serious environmental problems. The amount of waste marble from the processing stage is about 20 to 25% of the total processed stone. Egypt also suffers from the problem of expansive soil that occupies a large area of its lands, especially in the new cities that are built on these lands. The primary purpose of this study is to use this waste material in the soil stabilization in point of view utilization of this waste as local low‐cost materials and elimination of their negative environmental impacts. The waste marble dust was mixed with expansive soil samples with various percentages of 5%, 10%, 15%, 20%, and 25% by dry weight of soil. Different tests including Atterberg’s limits, standard Proctor compaction, unconfined compressive strength (UCS), California bearing ratio (CBR), swelling percentage, linear shrinkage (LS) tests, and XRF and XRD analyses were conducted for natural and marble dust stabilized soils. The soil mixtures used for UCS, CBR, and swell tests were compacted at the optimum moisture content (OMC) and maximum dry density (MDD) using the standard Proctor compaction method and cured for 7 days. The results of the tests showed that there are significant effects in enhancing the properties of expansive soils. Also, the results showed that as the percentage of the marble dust increases the plasticity index, the swelling potential of the expansive clayey soil decreases. Furthermore, the optimum moisture content decreases, and the maximum dry density increases. Also, UCS, CBR, and the calcite content of the soil mixtures increase with the increase in marble dust content.

Experimental investigation on the effects of elevated temperature on geotechnical behaviour of tropical residual soils

The engineering performance of soil after exposure to temperature is increasingly important in geotechnical and geoenvironmental engineering. Most thermal remediation of soil concentrates more on the remediation outcome and eliminates the effects temperature will have on the engineering properties of the soil itself. This paper presents the results of laboratory study conducted on two lateritic soils to investigate effect of elevated temperature difference on their geotechnical properties. The soils were classified as A-7-6 (8) and A-7-5 (4) based on the AASHTO soil classification system. After subjecting the soil samples to elevated temperatures (25, 50, 100, 150 and 200 °C), tests such as Atterberg limit, compaction, California bearing ratio (CBR), unconfined compressive strength (UCS) and scanning electron microscopy were carried on the samples. The results showed a decrease in Atterberg limit and increase in maximum dry density. The peak CBR for both the soils was obtained at 150 °C. The UCS increased with curing time but decreased with increased preheat temperature for both soils. The microanalysis result portrayed changes in morphological structure of fabrics which indicates a breakdown in the microstructural properties of the soil due to temperature variation. Generally, the statistical analysis of variance showed that temperature has significant effect on the geotechnical properties of residual soils.

Stabilization of clayey soil for subgrade using rice husk ash (RHA) and sugarcane bagasse ash (SCBA)

This document studies the stabilization of the soil used as a subgrade, by adding locally available materials such as rice husk ash (RHA) and sugarcane bagasse ash (SCBA). These aggregates were added to the soil in substitution by weight between 5%, 7.5% and 10%. By adding these, the expansiveness is reduced while the maximum dry density increases, in addition the tendency of CBR is increasing and then tends to decrease proportionally to the addition of the aforementioned aggregates. This indicates a peak in CBR and expandability. The best result obtained from CBR was 33.75% with the 5% replacement mixtures.

Strength and Workability Improvement Potential of Admixture of Corn Cob Ash and Cement for Stabilizing Lateritic Soil

A natural lateritic soil classified as A-7-5 (10) and CL based on AASHTO and USCS classification systems, was stabilized with up to 5% cement admixed with up to 12% CCA to assess their effect on its basic geotechnical properties such as particle size distribution, Atterberg limits, compaction, unconfined compressive strength and California bearing ratio. The liquid limit decreased and plastic limit increased while there is a reduction in corresponding plasticity index of the clay soil. There was an increase in Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) of the stabilized soil sample, which increased with the increasing content of CCA and cement. Both the Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) of the soil increased with increasing percentage of cement and CCA. Based on the results of this study, corn cob ash (CCA) cannot be used as a stand-alone stabilizer for this lateritic soil but with a more potent stabilizer for clay soil such as lime. It is therefore recommended that the mixture of 12% CCA and 2.5% cement could be used to stabilize A-7-5 (10) lateritic soil for use as subbase material and 12% CCA and 5.0% cement could be used to stabilize A-7-5 (10) lateritic soil for use as base material for improving pavement structure in terms of strength, stability and workability. Keywords: Lateritic soil, Corn cob ash, Cement, Stabilization, Strength and Workability DOI : 10.7176/JIEA/9-7-06 Publication date: December 31 st 2019

Potential of snail shell and palm kernel shell powders in improving engineering properties of clay

This research is aimed at using Snail Shell Powder (SSP) and Palm Kernel Shell Powder (PKSP) in stabilizing clay. Elemental and oxide compositions of the powders were determined and they revealed SSP is richer in CaO than PKSP. Sieve Analysis, Compaction, California Bearing Ratio (CBR) and Atterberg Limit were conducted on natural and stabilized soil mixture. The natural soil (A-7-6) was blended with SSP and PKSP at varying proportion of 2%, 4%, 6%, 8%, and 10% by dry weight of soil respectively and also combined at ratios not more than 10% total . Inclusion of additives increase the Maximum Dry Density (MDD) while it predominantly the Optimum Moisture Content (OMC) values of the stabilized soil mixture. Plasticity Index (PI) decrease with the addition of the powders with the best performance observed mostly with SSP blended soil. It was also found that the CBR values of soil increase with corresponding increase in dosage of the powders. Soil blended with 8% SSP offered the best result with increase in MDD from 1198 to 1300kg/m3 while the combined additives gave the best result at 2%SSP+8%PKSP addition with MDD increasing to 1266 kg/m3 and further reduction of OMC to 21%. The best results in PI were from Soil blended with 2% SSP and also 2%SSP+8PKSP with 6.25% and 9.2% respectively. For CBR, soil blended with 8% SSP and 2%SSP+8PKSP of combined ratio gave peak performances. The potential of these additives in improving soil properties and reducing construction cost of road are presented.Keywords: Palm kernel shell Powder, Snail shell powder, Clay stabilization, Geotechnical properties

Laboratory study of the effects of using magnesium slag on the geotechnical properties of cement stabilized soil

In this paper, the effects of magnesium slag and cement were investigated on the chemical, mechanical and microstructure parameters of soil. An increase was recorded in pH with increasing the content of both magnesium slag and cement, which is indicating an improvement in soil conditions for better implementation of pozzolanic and hydration reactions. Also, adding both substances led to the granulation of soil particles. An increase in maximum dry density (MDD) and optimum moisture content (OMC) was recorded by adding both additives.The uniaxial compressive strength test was investigated in three curing periods of 7, 28 and 56 days, which showed an increase in this parameter for the simultaneous and separate addition of both substances to the soil. The optimum content of magnesium slag was by 20% in this test and cement had the maximum content of 6%, which resulted in 14.3 MPa strength. The TCLP test was also performed to investigate the environmental issues in the sample with the abovementioned optimum percentages. By studying the microstructure, an improvement in soil structure was observed in the form of filled voids between the particles as well as density and continuity created between the particles.

Effect of Adding Mixture of (Concrete Waste and Asphalt Waste) on the Properties of Gypseous Soil

The Gypseous soil which is used is taken from Tikrit city in Salah Aldeen governorate and specially from Tikrit University from a depth (1.5-2) m. It's type is sandy gravely with a small percentage of silt and clay while the percentage of gypsum is (34-36) %. The tests on soil are standard proctor compaction, direct shear, collapsibility and California bearing ratio. The number of samples is (70). The effect of adding concrete waste (2, 4, 6 and 8%) and waste of Asphalt mixture (2, 4, 6 and 8) % on dry soil, as well as the effect of mixture of the optimum percentages of both additions on the properties of gypseous soil, is the aim of the study. Adding concrete waste at optimum percentage (6) % causes an increase in maximum dry density at (16)% and a decrease in optimum moisture content at (5) %. Whereas adding concrete mixture waste in its optimum percentage (2) % caused a decrease in maximum dry density values with an increase of optimum moisture content, and when adding a mixture of optimum percentage of waste, an increase happened in the M.D.D.(14)% with a decrease in O.M.C. at (4) %. Adding the optimum percentage (8) % for both, the value of cohesion increases (100) % when adding concrete waste with an increase in the angle of internal friction (14)% and a decrease in collapsibility in a percentage of (90)% , while adding waste of asphalt mixture shows an increase in cohesion value (112) % with a decrease in the angle of internal friction (2) % and a decrease in collapsibility in a percentage of (90) %, when adding mixture of optimum percentages the value of cohesion increase (108) % with an increase in angle of internal friction (14)% and a decrease in collapsibility in a percentage of (91) %. Values of California Bearing Ratio in dry and soaked condition increases (49) % when adding (8) % of concrete wastes which is the optimum percentage, while adding waste of asphalt mixture causes a decrease in the value of C.B.R. and the optimum percentage is (2) % , but adding optimum percentages mixture of them causes an increase in values of (52) % in dry condition and (53)% in soaked condition.

Influence of Granite Cutting Waste Addition on the Geotechnical Parameters of Cohesive Soil

The current study analyzes the effect of granite cutting waste addition on the properties of cohesive soil. Representative samples of cohesive soils were collected from the Mansehra and Balakot areas of Hazara, Pakistan and their major geotechnical properties determined following the standard ASTM procedures. The determined properties include the Atterberg limits, i.e. Liquid Limit (LL), Plastic Limit (PL), Plasticity Index (PI), and Maximum dry density, Optimum moisture contents, Un-confined compressive strength, Activity and Expansion. Both the soils are classified as active soils possessing high expansion capacity and low strength due to the presence of Ca-montmorillonites. Following an increment of 5%, up to 25% streaks of cutting waste from Susalgali and Baffa granites were added to the Mansehra soil and Balakot soil respectively. A thorough analysis of the test results reveals a continuous decrease in the Atterberg limits, optimum moisture contents and expansion capacity, and increase in the maximum dry density and overall strength of both the soils with increasing amounts of the added granite cutting waste streaks. The reduction in Atterberg limits, optimum moisture contents and expansion capacity reflects the low activity and lower absorption capacity of the added granite. Besides, the concomitant increase in strength and maximum dry density of the treated soils suggests suitability of granite waste addition as a potential means for enhancing bearing capacity and reducing settlement issues in civil engineering

Effect of Bentonite Addition on Geotechnical Properties of Oil-Contaminated Sandy Soil

Oil and its derivatives not only change the chemical and biological properties of the soils, but also affect their geotechnical properties. Effects of oil contamination on a sandy soil which mixed with bentonite was assessed in terms of compaction, shear strength, and consolidation behavior. The experiments were carried out by polluting dry sandy soil with 2.5, 5, 7.5, 10% w/w crude oil at different bentonite contents (0, 5, 10, 15, 20% w/w). Results of compaction tests indicated that at a fixed bentonite content, with increasing crude oil content, the maximum dry density increases, while the optimum water content decreases. Similarly, at a fixed contaminant content, increasing the bentonite content in the soil leads to increase in soil maximum dry density and the optimum moisture content. Moreover, direct shear tests revealed that at a specific bentonite content, higher contamination concentration causes lower internal friction angle. The effect of oil content on the coefficient of consolidation (Cv) and void ratio of soils with 0, 5, 10, 15, and 20 percent bentonite contents was studied. The results of consolidation tests indicated that at a fixed bentonite content Cv has an overall increasing pattern which is in its maximum amount at 5% oil content.

SUITABILITY OF RICE HUSK ASH TREATED BLACK COTTON SOIL FOR WASTE CONTAINMENT APPLICATION

This paper presents an experimental study aimed at assessing the suitability of rice husk ash (RHA) treated black cotton soil as a barrier in Municipal Solid Waste (MSW) containment facility. Laboratory tests were conducted on black cotton soil treated with 5, 10 and 15% RHA at moulding water contents of 2 and 4% on both wet and dry sides of optimum moisture content (OMC) using British Standard Heavy (BSH) compactive effort. Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS), and unconfined compressive strength (UCS) tests were conducted on all the samples. The results obtained indicated that the soil was classified as A-7-5(18) according to the American Association of States Highway and Transport Officials (AASHTO) classification system and Silt of high plasticity (MH) in accordance with the Unified Soil Classification System (USCS). It was observed that addition of RHA was accompanied with decrease in the plasticity index from 24 to as low as 3%. An improvement in the moisture-density relationship of the soils showed an increase in Maximum Dry Density (MDD) from 1.46 to 1.52 Mg/m3 as well as a decrease from 24.5 to 21.2% in OMC. The increase in RHA contents up to 10% brought about an improvement in the strength of the soil specimens by almost 332.4kN/m2 at 2% on the dry side of OMC. The VSS decreases with increase in RHA content to achieve the minimum shrinkage strain of 4.1% at 5% RHA treatment.

SUITABILITY OF RICE HUSK ASH TREATED BLACK COTTON SOIL FOR WASTE CONTAINMENT APPLICATION

This paper presents an experimental study aimed at assessing the suitability of rice husk ash (RHA) treated black cotton soil as a barrier in Municipal Solid Waste (MSW) containment facility. Laboratory tests were conducted on black cotton soil treated with 5, 10 and 15% RHA at moulding water contents of 2 and 4% on both wet and dry sides of optimum moisture content (OMC) using British Standard Heavy (BSH) compactive effort. Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS), and unconfined compressive strength (UCS) tests were conducted on all the samples. The results obtained indicated that the soil was classified as A-7-5(18) according to the American Association of States Highway and Transport Officials (AASHTO) classification system and Silt of high plasticity (MH) in accordance with the Unified Soil Classification System (USCS). It was observed that addition of RHA was accompanied with decrease in the plasticity index from 24 to as low as 3%. An improvement in the moisture-density relationship of the soils showed an increase in Maximum Dry Density (MDD) from 1.46 to 1.52 Mg/m3 as well as a decrease from 24.5 to 21.2% in OMC. The increase in RHA contents up to 10% brought about an improvement in the strength of the soil specimens by almost 332.4kN/m2 at 2% on the dry side of OMC. The VSS decreases with increase in RHA content to achieve the minimum shrinkage strain of 4.1% at 5% RHA treatment.

Influence of thermal loading on index and physicochemical properties of Barmer bentonite

Abstract The concept of the deep geological repository (DGR) has been widely accepted for the safe disposal of high-level nuclear waste (HLW). Compacted bentonite/bentonite-sand mixture is considered as buffer material in the deep geological repository due to its favorable physicochemical and hydro-mechanical properties. The bentonite buffer is expected to be exposed to high temperature for a long duration because the heat released from the waste canister and due to the geo-thermal gradient inside the deep geological repository. The temperature from the waste canister can go initially as high as 200 °C and probably reduce to ambient temperature upon the decay of the waste material. This long duration temperature variation induces a thermal loading on the bentonite buffer, affecting its index, physicochemical and hydro-mechanical properties. Hence there is a need to critically examine the effect of the induced thermal loading on the long-term performance of the buffer as this study will be quite useful for the preliminary understanding before fixing its design values for the use as a part of engineered barrier system (EBS) in DGR. In the present study, two bentonites (Barmer 1 (B1) and Barmer 2 (B2)) from Barmer district of Rajasthan, India, was subjected to four temperature levels, i.e., 60 °C, 110 °C, 150 °C and 200 °C for a time duration of 3, 7, 15, 21, 28 days. Changes in the physicochemical properties of both bentonites were observed and reported. The decrease in the Atterberg's limit, swelling, specific gravity, optimum moisture content, pH and exchangeable monovalent cation and increase in maximum dry density was recorded with an increase in temperature as well as with the duration of heating.

Investigation of geotechnical properties of clayey soils contaminated with gasoil using Response Surface Methodology (RSM)

Oil and its derivatives such as gasoline, motor oil and gasoil are using in various industrial and non-industrial sectors as the main energy sources all over the world. However, within the process of exploration, transportation and storage they may spill or leaking into the soil. Among them the gasoil which is more widely used in different parts and machineries has the largest contribution in contaminating lands. Purgation of these areas is not always feasible or possible. Instead, they can be used in many engineering practices if the level of contamination is not high. In such cases knowing the geotechnical properties of these areas are of great necessity and importance. In this study, extensive laboratory tests were performed on remolded clayey samples mixed with gasoil to evaluate their geotechnical properties. The Response Surface Methodology (RSM) was used to analyze the data and find behavioral equations. According to testing results and RSM outputs a decrease in Atterberg limits, and increase in maximum dry density happen by increasing contamination. Also their shear strength parameters (c and f) both exhibit a turning change point at 8% gasoil content, while their variations trends are quite in opposite directions

Influence of Temperature on the Engineering Properties of Selected Tropical Black Clays

Laboratory tests were carried out to examine the effect of temperature on the engineering properties of selected tropical black clays (known as black cotton soils, BCS) in Northeastern Nigeria. Black cotton soil was sourced from two borrow pits in Numan and Biu and each subjected to geotechnical investigations. Soil samples were subjected to high temperatures of 25, 50, 75, 100 and 150 \({^{\circ }}\)C for 240 min, respectively. Natural soils were classified as A-7-6(15) and A-7-6(11) for Numan and Biu black cotton soils, respectively, using the AASHTO soil classification system. Tests carried out included Atterberg limits, free swell, compaction and California bearing ratio. Statistical analysis was carried out on the obtained results using analysis of variance with the Microsoft Excel Analysis Tool Pak Software Package to determine the levels of significance of the effect of temperature variation on the properties of the soil. Mini-tab R15 software and XLSTART 2014 statistical tool incorporated as an add-in in Microsoft Excel were used for the regression modeling and correlation analysis, respectively. Test results showed a decrease in liquid limit and plastic limit, an increase in maximum dry density, with a corresponding decrease in the California bearing ratio. No general trend was established for plasticity index and optimum moisture content. Generally, results of the statistical analysis showed that temperature has significant effect on the tested soil samples and positively improved the engineering properties of the selected soil samples. Based on results obtained, an optimal temperature of 100 \({^{\circ }}\)C is recommended for remediation and improving the geotechnical properties of the treated soils.

Study of Compaction Characteristics of Soil with the Addition of Slate Mining Waste

Objectives: This paper brings out the results of an experimental programme carried out at National Institute of Technology, Hamirpur to evaluate the effectiveness of using slate quarry waste for soil stabilization by studying the compaction characteristics of various proportions of slate waste in native soil, as a pre-requirement to reach at soil-slate mix for shear strength and settlement testing for use as a sub grade material for foundations of structures and pavements. Methods/Statistical Analysis: Disturbed sampling of soil was done and was classified according to Indian Standard Soil Classification System (ISSCS), using Liquid limit and Plasticity index. Slate waste was sampled and Sieve analysis was performed. Light compaction tests were performed in order to get the Maximum Dry Density and Optimum Moisture content of soil with slate mining waste in various proportions. Findings: The soil was found to have liquid limit and plastic limit of 46.0833% and 26.1570 % respectively. According to ISSCS, Soil was found to be clay of medium compressibility. Slate waste with cu and ccof9.04 and 0.67 respectively was utilized for the study. The Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) was found to be 24.989% and 1.497 g/cc, 32% and 1.95g/cc for soil and slate waste respectively. Variation of OMC and MDD with slate waste (%) added was analysed. The results show that the addition of waste material has increased the OMC as well as the MDD. An increase in MDD depicts a stable soil. The increase in OMC is due to the water absorption of slate waste. Application/Improvements: These results can be further used for study of strength, settlement behaviour, and slope stability of the soil-slate waste mix. It can be utilized for economics in pavements and improvement of Sub grade of pavements and buildings.