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

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

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

CBR 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 CBR values of composite soil (i.e. sand composite). A series of laboratory CBR tests carried out to evaluate fiber effect on CBR values 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 20 mm to 50 mm and fiber content were varied from 1% and 3%. For each test, CBR values were calculated and compared. The results proved that inclusion of fiber affected CBR values of sand composite so that increasing in fiber content and length caused increasing in CBR

Investigation on shrinkage behaviour of kaolin clay

As evaporation prevails, soils lose water and shrink upon desiccation, which lead to formation of desiccation cracks. The cracking of desiccated clay soils is problematic to many civil structures hence an adequate understanding of the desiccation cracking process is of great significance. To build this understanding, knowledge of how crack forms, their position, orientation and connectivity in space are necessary. This paper aims to investigate shrinkage problem deeply. A series of shrinkage test were conducted. The container dimensions were 50mm X50mm X 50mm. the soil was selected as kaolin clay. Different initial moisture content of 45% and 40% considered. The results proved that water content decreased as desiccation rate increased. The engineering graph of change in water content versus time and shrinkage strain versus change in water content was plotted for each test. The desiccation curves shows similar behaviour for different initial moisture content as finally reached the balance with local climate

A Review on The Lime and Fly ash Application in Soil Stabilization

Nowadays, inefficient properties of soils are a critical issue in engineering projects. In some cases, improve the characteristic of unsuitable soils is a fundamental step for making construction. This review paper presents the results of research on soil stabilization with lime and fly ash. Soil stabilization performed the use of technique to adding a binder to the soil in order to improve the engineering performance of soil. Researches were illustrated that adding the additives leads to progress in workability and mechanical behaviour of soil after stabilization. Lime and fly ash as local natural and industrial resources were applied for chemical stabilization. These additives could improve the mechanical properties of soil such as strength, swelling, plasticity index and compressibility. The obtained results were indicated that, for progressing in soil properties the combination of lime and fly ash might be more effective than use of only lime or fly ash