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Laboratory oedometer tests were conducted to investigate the effect of small intermediate reloading-unloading (r-u) cycles (in over-consolidated range) on a general unloading path and that of small unloading-reloading (u-r) cycles on a general reloading path on the permanent deformation of Ariake clay samples. The test results indicate that the permanent deformation increased with r-u cycles, and decreased with u-r cycles. The test results were simulated well using an existing static u-r model. Then two case histories of land-subsidence were analyzed. The engineering significance of considering daily variations of ground-water levels on the simulated results has been confirmed by comparing with the field measurements.

Laboratory oedometer tests were conducted to investigate the effect of small intermediate reloading-unloading (r-u) cycles (in over-consolidated range) on a general unloading path and that of small unloading-reloading (u-r) cycles on a general reloading path on the permanent deformation of Ariake clay samples. The test results indicate that the permanent deformation increased with r-u cycles, and decreased with u-r cycles. The test results were simulated well using an existing static u-r model. Then two case histories of land-subsidence were analyzed. The engineering significance of considering daily variations of ground-water levels on the simulated results has been confirmed by comparing with the field measurements.

Laboratory oedometer tests were conducted to investigate the effect of small intermediate reloading-unloading (r-u) cycles (in over-consolidated range) on a general unloading path and that of small unloading-reloading (u-r) cycles on a general reloading path on the permanent deformation of Ariake clay samples. The test results indicate that the permanent deformation increased with r-u cycles, and decreased with u-r cycles. The test results were simulated well using an existing static u-r model. Then two case histories of land-subsidence were analyzed. The engineering significance of considering daily variations of ground-water levels on the simulated results has been confirmed by comparing with the field measurements.

Laboratory oedometer tests were conducted to investigate the effect of small intermediate reloading-unloading (r-u) cycles (in over-consolidated range) on a general unloading path and that of small unloading-reloading (u-r) cycles on a general reloading path on the permanent deformation of Ariake clay samples. The test results indicate that the permanent deformation increased with r-u cycles, and decreased with u-r cycles. The test results were simulated well using an existing static u-r model. Then two case histories of land-subsidence were analyzed. The engineering significance of considering daily variations of ground-water levels on the simulated results has been confirmed by comparing with the field measurements.

Compressibility characteristics of a lightweight cemented clay are important issues for deformation analysis. This paper attempts to analyze and assess the compressibility characteristics of lightweight cemented clays. Three types of clay, kaolin, Bangkok clay and bentonite, representative of non- to high swelling clays are used for this study. It is found that a lightweight cemented clay is stable in the meta-stable state. The void ratio of a lightweight cemented clay is the sum of the void ratio sustained by the intrinsic soil fabric (destructured void ratio) and the additional void ratio due to cementation. At post yield state, the additional void ratio is made of two parts, the part that is inversely proportional to effective vertical stress and the residual additional void ratio, esr, which cannot be eliminated by the increase in effective vertical stress. The esr is mainly dependent upon the mineralogy or soil type (swelling potential). The suggested esr values are approximately 0.49 for kaolin, 0.18 for Bangkok clay and 0.10 for bentonite. The rate of destructuring, b is mainly dependent upon the soil structure (degree of cementation and fabric reflected by the initial void ratio and swelling potential). The relationships between esr versus liquid limit void ratio eL and between b versus yield stress, initial void ratio and eL are proposed. Based on the two proposed relationships, a practical (simple and rational) method for assessing the compressibility of lightweight cemented clay with various soil structures is suggested. The prediction method is useful not only for the quick determination of a compression curve with acceptable error, but also for the examination of the test results. •Conduct compression tests on lightweight cemented non- to high swelling clays.•Predict the compression curves using the destructuring framework.•Explain role of water, cement, air and swelling potential on model parameters.•Proposed rational empirical equation to determine th

Compressibility characteristics of a lightweight cemented clay are important issues for deformation analysis. This paper attempts to analyze and assess the compressibility characteristics of lightweight cemented clays. Three types of clay, kaolin, Bangkok clay and bentonite, representative of non- to high swelling clays are used for this study. It is found that a lightweight cemented clay is stable in the meta-stable state. The void ratio of a lightweight cemented clay is the sum of the void ratio sustained by the intrinsic soil fabric (destructured void ratio) and the additional void ratio due to cementation. At post yield state, the additional void ratio is made of two parts, the part that is inversely proportional to effective vertical stress and the residual additional void ratio, esr, which cannot be eliminated by the increase in effective vertical stress. The esr is mainly dependent upon the mineralogy or soil type (swelling potential). The suggested esr values are approximately 0.49 for kaolin, 0.18 for Bangkok clay and 0.10 for bentonite. The rate of destructuring, b is mainly dependent upon the soil structure (degree of cementation and fabric reflected by the initial void ratio and swelling potential). The relationships between esr versus liquid limit void ratio eL and between b versus yield stress, initial void ratio and eL are proposed. Based on the two proposed relationships, a practical (simple and rational) method for assessing the compressibility of lightweight cemented clay with various soil structures is suggested. The prediction method is useful not only for the quick determination of a compression curve with acceptable error, but also for the examination of the test results. •Conduct compression tests on lightweight cemented non- to high swelling clays.•Predict the compression curves using the destructuring framework.•Explain role of water, cement, air and swelling potential on model parameters.•Proposed rational empirical equation to determine th

Compressibility characteristics of a lightweight cemented clay are important issues for deformation analysis. This paper attempts to analyze and assess the compressibility characteristics of lightweight cemented clays. Three types of clay, kaolin, Bangkok clay and bentonite, representative of non- to high swelling clays are used for this study. It is found that a lightweight cemented clay is stable in the meta-stable state. The void ratio of a lightweight cemented clay is the sum of the void ratio sustained by the intrinsic soil fabric (destructured void ratio) and the additional void ratio due to cementation. At post yield state, the additional void ratio is made of two parts, the part that is inversely proportional to effective vertical stress and the residual additional void ratio, esr, which cannot be eliminated by the increase in effective vertical stress. The esr is mainly dependent upon the mineralogy or soil type (swelling potential). The suggested esr values are approximately 0.49 for kaolin, 0.18 for Bangkok clay and 0.10 for bentonite. The rate of destructuring, b is mainly dependent upon the soil structure (degree of cementation and fabric reflected by the initial void ratio and swelling potential). The relationships between esr versus liquid limit void ratio eL and between b versus yield stress, initial void ratio and eL are proposed. Based on the two proposed relationships, a practical (simple and rational) method for assessing the compressibility of lightweight cemented clay with various soil structures is suggested. The prediction method is useful not only for the quick determination of a compression curve with acceptable error, but also for the examination of the test results. •Conduct compression tests on lightweight cemented non- to high swelling clays.•Predict the compression curves using the destructuring framework.•Explain role of water, cement, air and swelling potential on model parameters.•Proposed rational empirical equation to determine th

Compressibility characteristics of a lightweight cemented clay are important issues for deformation analysis. This paper attempts to analyze and assess the compressibility characteristics of lightweight cemented clays. Three types of clay, kaolin, Bangkok clay and bentonite, representative of non- to high swelling clays are used for this study. It is found that a lightweight cemented clay is stable in the meta-stable state. The void ratio of a lightweight cemented clay is the sum of the void ratio sustained by the intrinsic soil fabric (destructured void ratio) and the additional void ratio due to cementation. At post yield state, the additional void ratio is made of two parts, the part that is inversely proportional to effective vertical stress and the residual additional void ratio, esr, which cannot be eliminated by the increase in effective vertical stress. The esr is mainly dependent upon the mineralogy or soil type (swelling potential). The suggested esr values are approximately 0.49 for kaolin, 0.18 for Bangkok clay and 0.10 for bentonite. The rate of destructuring, b is mainly dependent upon the soil structure (degree of cementation and fabric reflected by the initial void ratio and swelling potential). The relationships between esr versus liquid limit void ratio eL and between b versus yield stress, initial void ratio and eL are proposed. Based on the two proposed relationships, a practical (simple and rational) method for assessing the compressibility of lightweight cemented clay with various soil structures is suggested. The prediction method is useful not only for the quick determination of a compression curve with acceptable error, but also for the examination of the test results. •Conduct compression tests on lightweight cemented non- to high swelling clays.•Predict the compression curves using the destructuring framework.•Explain role of water, cement, air and swelling potential on model parameters.•Proposed rational empirical equation to determine th

Cement stabilization is extensively used to improve engineering properties of soft saline clays. The effect of salinity, which is modified by geological and climate changes, on the strength development in cement admixed saline clay is investigated in this paper. For a particular curing time and salt content, the strength development in saline clay admixed with cement is governed by the clay-water/cement ratio, wc/C. The strength increases with the decrease of wc/C. The increase in salt content for a particular water content decreases the inter-particle attraction of the clay and the cementation bond strength. Hence, for the same clay-water/cement ratio, the strength of the cement admixed saline clay decreases with increasing salt content. In order to increase strength, and improve the economic and environmental impact, fly ash (FA) and biomass ash (BA) can be used to substitute Portland cement. The influence of FA and BA on the strength development of cement admixed saline clay was investigated with unconfined compressive (UC) test and thermogravimetric (TG) analysis. FA and BA were dispersing materials, increasing the reactive surface of the cement grains, and hence strength increases as well. The clay-water/cement ratio hypothesis was used successfully to analyze and assess the strength development of blended cement admixed saline clay at various salt contents. An addition of 25% ash can replace up to 15.8% of cement.

Cement stabilization is extensively used to improve engineering properties of soft saline clays. The effect of salinity, which is modified by geological and climate changes, on the strength development in cement admixed saline clay is investigated in this paper. For a particular curing time and salt content, the strength development in saline clay admixed with cement is governed by the clay-water/cement ratio, wc/C. The strength increases with the decrease of wc/C. The increase in salt content for a particular water content decreases the inter-particle attraction of the clay and the cementation bond strength. Hence, for the same clay-water/cement ratio, the strength of the cement admixed saline clay decreases with increasing salt content. In order to increase strength, and improve the economic and environmental impact, fly ash (FA) and biomass ash (BA) can be used to substitute Portland cement. The influence of FA and BA on the strength development of cement admixed saline clay was investigated with unconfined compressive (UC) test and thermogravimetric (TG) analysis. FA and BA were dispersing materials, increasing the reactive surface of the cement grains, and hence strength increases as well. The clay-water/cement ratio hypothesis was used successfully to analyze and assess the strength development of blended cement admixed saline clay at various salt contents. An addition of 25% ash can replace up to 15.8% of cement.

Cement stabilization is extensively used to improve engineering properties of soft saline clays. The effect of salinity, which is modified by geological and climate changes, on the strength development in cement admixed saline clay is investigated in this paper. For a particular curing time and salt content, the strength development in saline clay admixed with cement is governed by the clay-water/cement ratio, wc/C. The strength increases with the decrease of wc/C. The increase in salt content for a particular water content decreases the inter-particle attraction of the clay and the cementation bond strength. Hence, for the same clay-water/cement ratio, the strength of the cement admixed saline clay decreases with increasing salt content. In order to increase strength, and improve the economic and environmental impact, fly ash (FA) and biomass ash (BA) can be used to substitute Portland cement. The influence of FA and BA on the strength development of cement admixed saline clay was investigated with unconfined compressive (UC) test and thermogravimetric (TG) analysis. FA and BA were dispersing materials, increasing the reactive surface of the cement grains, and hence strength increases as well. The clay-water/cement ratio hypothesis was used successfully to analyze and assess the strength development of blended cement admixed saline clay at various salt contents. An addition of 25% ash can replace up to 15.8% of cement.

Lightweight cemented clays have wide applications in infrastructure rehabilitation and in construction of new facilities. The strength and compression characteristics of lightweight cemented clays with non- to high swelling potential are investigated and presented in this article. The workable state, the optimum water content to produce the lightweight cemented clay, is about 1.9 times the liquid limit. The void/cement ratio, V/C, which is defined as the ratio of the void volume of clay to the cement volume, is proved to be the prime parameter governing the strength and compression characteristics of lightweight cemented clays. The fabric (arrangement of clay particles, clusters and pore spaces) reflected from both air foam content and water content is taken into consideration by the void volume while the inter-particle forces (levels of cementation bond) are governed by the input of cement (cement volume). A strength equation in terms of V/C at a particular curing time is introduced using Abram's law as a basis. From the critical analysis of test results, a mix design method to attain the target strength and unit weight is suggested. This method is useful for both engineering and economic viewpoints. (C) 2012 Elsevier B.V. All rights reserved.

Lightweight cemented clays have wide applications in infrastructure rehabilitation and in construction of new facilities. The strength and compression characteristics of lightweight cemented clays with non- to high swelling potential are investigated and presented in this article. The workable state, the optimum water content to produce the lightweight cemented clay, is about 1.9 times the liquid limit. The void/cement ratio, V/C, which is defined as the ratio of the void volume of clay to the cement volume, is proved to be the prime parameter governing the strength and compression characteristics of lightweight cemented clays. The fabric (arrangement of clay particles, clusters and pore spaces) reflected from both air foam content and water content is taken into consideration by the void volume while the inter-particle forces (levels of cementation bond) are governed by the input of cement (cement volume). A strength equation in terms of V/C at a particular curing time is introduced using Abram's law as a basis. From the critical analysis of test results, a mix design method to attain the target strength and unit weight is suggested. This method is useful for both engineering and economic viewpoints. (C) 2012 Elsevier B.V. All rights reserved.

Lightweight cemented clays have wide applications in infrastructure rehabilitation and in construction of new facilities. The strength and compression characteristics of lightweight cemented clays with non- to high swelling potential are investigated and presented in this article. The workable state, the optimum water content to produce the lightweight cemented clay, is about 1.9 times the liquid limit. The void/cement ratio, V/C, which is defined as the ratio of the void volume of clay to the cement volume, is proved to be the prime parameter governing the strength and compression characteristics of lightweight cemented clays. The fabric (arrangement of clay particles, clusters and pore spaces) reflected from both air foam content and water content is taken into consideration by the void volume while the inter-particle forces (levels of cementation bond) are governed by the input of cement (cement volume). A strength equation in terms of V/C at a particular curing time is introduced using Abram's law as a basis. From the critical analysis of test results, a mix design method to attain the target strength and unit weight is suggested. This method is useful for both engineering and economic viewpoints. (C) 2012 Elsevier B.V. All rights reserved.

Cement stabilization is extensively used to improve engineering properties of soft saline clays. The effect of salinity, which is modified by geological and climate changes, on the strength development in cement admixed saline clay is investigated in this paper. For a particular curing time and salt content, the strength development in saline clay admixed with cement is governed by the clay-water/cement ratio, wc/C. The strength increases with the decrease of wc/C. The increase in salt content for a particular water content decreases the inter-particle attraction of the clay and the cementation bond strength. Hence, for the same clay-water/cement ratio, the strength of the cement admixed saline clay decreases with increasing salt content. In order to increase strength, and improve the economic and environmental impact, fly ash (FA) and biomass ash (BA) can be used to substitute Portland cement. The influence of FA and BA on the strength development of cement admixed saline clay was investigated with unconfined compressive (UC) test and thermogravimetric (TG) analysis. FA and BA were dispersing materials, increasing the reactive surface of the cement grains, and hence strength increases as well. The clay-water/cement ratio hypothesis was used successfully to analyze and assess the strength development of blended cement admixed saline clay at various salt contents. An addition of 25% ash can replace up to 15.8% of cement.

Lightweight cemented clays have wide applications in infrastructure rehabilitation and in construction of new facilities. The strength and compression characteristics of lightweight cemented clays with non- to high swelling potential are investigated and presented in this article. The workable state, the optimum water content to produce the lightweight cemented clay, is about 1.9 times the liquid limit. The void/cement ratio, V/C, which is defined as the ratio of the void volume of clay to the cement volume, is proved to be the prime parameter governing the strength and compression characteristics of lightweight cemented clays. The fabric (arrangement of clay particles, clusters and pore spaces) reflected from both air foam content and water content is taken into consideration by the void volume while the inter-particle forces (levels of cementation bond) are governed by the input of cement (cement volume). A strength equation in terms of V/C at a particular curing time is introduced using Abram's law as a basis. From the critical analysis of test results, a mix design method to attain the target strength and unit weight is suggested. This method is useful for both engineering and economic viewpoints. (C) 2012 Elsevier B.V. All rights reserved.