Experimental approach to investigate reinforced clay

Soil reinforcement with discrete flexible fibres has always been an issue for further research. In Geotechnical engineering field, the research on sandy soil has considerably been more than the clayey one. The main reason for this lack can be expressed as the complexity of clayey material due to their cohesion and interaction between clay and reinforcement.The present research aims to show possibility of discrete fibre usage in clay. For this purpose, selection of material has been conducted with special care to make the project outcome applicable to industry projects. The fibre which was used for this research prepared by BASF Company in Western Australia and currently is used in fibre reinforced concrete for infrastructure projects. Kaolin has been used as soil part and provided by Prestige Company.Experimental approach was applied to investigate the effect of different parameters on composite soil strength. These tests cover the variety range of soil mechanics tests from compaction tests to triaxial compression tests. The results from all the tests were presented in the thesis.A theoretical model was also developed for clayey material for the first time with the use of modified cam clay model to predict the behaviour of samples precisely. This model is based on the rule of mixture and considers the effect of soil and fibre separately. The model was validated with the results from CD triaxial test

CBR test on fibre reinforced silty sand

Geosynthetic fibres are an established family of geomaterials used in a wide variety of civil engineering applications such as pavement systems. In pavement design, CBR ratio count as an important parameter. This study aims to investigate effect of fibre inclusion on CBR ratio. A series of laboratory investigation were carried out to evaluate effects of reinforcing the sub grade soil in pavement system with randomly distributed plastic fibres. In this study, one type of soil (i.e silty sand) and two type of fibre were used. CBR test were conducted on unreinforced samples as well as reinforced ones at different fibre contents (i.e. 0.1%, 0.3%) and different fibre length (i.e. 10mm , 20 mm and 40mm).The results of CBR test showed that the CBR ratio for reinforced silty sand increased even more than two times in some cases as fibre content and fibre length increased. The results proved that application of short randomly distributed fibre is a good method to apply in practical projects

Effective Parameters on Strength of Reinforced Clayey Sand

Soils and their related behavior has always been the subject of many studies. Recent researches show some interests in investigation of inclusion of randomly distributed fiber in soil. This study focuses on effect of fiber inclusion on the strength and other parameters of clayey sand composite material. The first part of this study is related to effective parameters on strength of the clayey sand composite with using natural fiber and plastic fiber with different fiber contents and length. UCS tests were carried out to investigate behavior of the composite under different condition. The fiber percentage varied from 0 % (for unreinforced samples) to 4% and fiber length varied from 8mm to 25mm. The fiber length and fiber content are found to play important roles in the strength of fiber reinforced composite. Furthermore it was observed that ductility of sample increased by fiber inclusion

Effect of Fibre Content on Compressive Strength of Reinforced Soil

This paper aims to investigate effect of using fibre on strength of composite. A series of laboratory tests has been carried out to investigate the using of plastic fibre as reinforcement to increase the strength of the soil composite. Fibre percentage varied from 0% (for unreinforced samples) to 0.3%. Two methods of compaction test were used (i.e. Standard and Modified compaction methods). Unconfined compression tests were conducted in this study. The objective of using unconfined compression test was to determine the UU (unconsolidated, undrained) strength of a cohesive soil in an inexpensive manner. The results showed that fibre dosage was significant factor that affected the strength of the soil specimens. The results also indicated increasing in fibre content caused increase in compressive strength. The strength and ductility considerably increased with increasing the fibre content. Furthermore, Unconfined Compression Strength (UCS) found to be slightly greater for Modified method than Standard one. In addition, a series of tests have been conducted to examine permeability coefficient of the specimens. The results showed that length and fibre dosage had considerable effects on permeability of samples. It was proved that increase in fibre content and length caused increase in hydraulic conductivity

Effect of clay layer thickness on desiccation and cracking

Clay materials are usually part of geotechnical projects such as slopes, embankment dams and landfills. Crack problem in clayey soil is one of the most destructive phenomenon as can affect the stability and efficiency of geotechnical projects. Thermal, mechanical and volume changes which lead to stress in soil can be cause of cracking. A series of desiccation tests were carried out to investigate effect of thickness of clay layer in crack pattern. Circular container selected with 150 mm diameter. Soil thickness was changed during the tests (i.e. 10mm, 15mm, and 30mm). Kaolin clay was used as soil part. The container material selected as metal. The results from the tests proved that thickness of soil is a significant parameter in desiccation tests and with increasing in thickness crack pattern is moved to orthogonal manner. During the tests also effect of fibre inclusion observed and showed that fibre inclusion had significant effect on crack density of the sample

Study on sand and paper reinforcement

Reinforced soil has been among the most effective soil modification materials. Its use has been expanded rapidly into civil engineering, geotechnical engineering and pavement engineering. Reinforcing subgarde in pavement systems has always been an issue. This study focuses on effect of paper inclusion on the modulus of elasticity of subgrade material. Paper was used for this investigation. Paper contents and aspect ratio have been changed during these tests. The paper percentage varied from 0 % (for unreinforced samples) to 20%. Sand was used as sub grade material. Unconfined compression tests were carried out to investigate behaviour of the composite under different condition. The paper reinforcement length and paper reinforcement content found to play important rule on the modulus of elasticity of paper reinforced samples. Effect of paper content found to be more significant compare to paper length

Compaction parameters of reinforced clayey sand

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fibre inclusion on compaction characteristic of composite soil (i.e. clayey sand composite). A series of laboratory tests carried out to evaluate fibre effect on optimum water content and maximum dry unit weight of composite soils. Clayey sand was selected as soil part of the composite and natural fibre was used as reinforcement. The fibre parameters differed from one test to another, as fibre length varied from 15 mm to 30 mm and fibre content were selected as 0.5% and 0.7%. For each test, compaction curved derived and the results were compared. The results proved that inclusion of fibre affected compaction behaviour of samples so that increasing in fibre content and length caused increasing in Optimum Moisture Content (OMC) and slightly decreased maximum dry unit weight

Laboratory Investigation on the Compaction Properties of Lime and Fly Ash Composite

Soil stabilization has been implemented for improving soils, which have inadequate engineering properties. Chemical stabilization method is mixing additives, such as lime and fly ash with soil to modify soil characteristics. This paper describes a research that carried out to study the effects of lime and fly ash in compaction properties of sand based on the seven specimens (i.e., 1 sand, 2 lime, 2 fly ashes and 4 mixture of lime-fly ash). The effectively of lime (%1 and %2), fly ash( %5 and %10) ash and the combination of each mixture were investigated in this research study in order to evaluation the maximum dry density and optimum moisture content of sand. The given result of lime and fly ashspecimens illustrated that fly ash stabilization is more effective than lime treatment alone. However, utilization of combination of additives leads to optimum effect on compactability property of sand

Permeability test on reinforced clayey sand

Composite soils have been widely used in civil engineering applications, especially in slopes, embankment dam and landfills. This paper aims to investigate effect of fiber inclusion on permeability of composite soil (i.e. sand composite). A series of laboratory permeability tests carried out to evaluate fiber effect on hydraulic conductivity behavior of composite sand. Clayey sand was selected as soil part of the composite and natural fiber was used as reinforcement. The fiber parameters differed from one test to another, as fiber length were changed from 10 mm to 25 mm and fiber content were varied from 0.1% and 0.3%. For each test, permeability coefficients derived and the results were compared. The results proved that inclusion of fiber affected hydraulic conductivity of sand composite so that increasing in fiber content and length caused increasing in permeability coefficients

Investigation on silty sand and paper reinforcement

Reinforced soil has been among the most effective soil modification materials. Its use has been expanded rapidly into civil engineering, geotechnical engineering and pavement engineering. Reinforcing subgarde in pavement systems has always been an issue. This study focuses on effect of paper inclusion on the modulus of elasticity of subgrade material. Paper was used for this investigation. Paper contents and aspect ratio have been changed during these tests. The paper percentage varied from 0 % (for unreinforced samples) to 20%. Silty sand was used as sub grade material. Unconfined compression tests were carried out to investigate behaviour of the composite under different condition. The paper reinforcement length and paper reinforcement content found to play important rule on the modulus of elasticity of paper reinforced samples. Effect of paper content found to be more significant compare to paper length