An experimental program was undertaken to study the individual and admixed effects of lime and fly ash on the geotechnical characteristics of expansive soil.Lime and fly ash were added to the expansive soil at 4%-6% a...An experimental program was undertaken to study the individual and admixed effects of lime and fly ash on the geotechnical characteristics of expansive soil.Lime and fly ash were added to the expansive soil at 4%-6% and 40%-50% by dry weight of soil,respectively.Testing specimens were determined and examined in chemical composition,grain size distribution,consistency limits,compaction,CBR,free swell and swell capacity.The effect of lime and fly ash addition on reducing the swelling potential of an expansive soil is presented.It is revealed that a change of expansive soil texture takes place when lime and fly ash are mixed with expansive soil.Plastic limit increases by mixing lime and liquid limit decreases by mixing fly ash,which decreases plasticity index.As the amount of lime and fly ash is increased,there are an apparent reduction in maximum dry density,free swell and swelling capacity under 50 kPa pressure,and a corresponding increase in the percentage of coarse particles,optimum moisture content and CBR value.Based on the results,it can be concluded that the expansive soil can be successfully stabilized by lime and fly ash.展开更多
Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and sal...Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.展开更多
Volume instability of expansive soils due to moisture fluctuations is often disastrous,causing severe damages and distortions in the supported structures.It is,therefore,necessary to adequately improve the performance...Volume instability of expansive soils due to moisture fluctuations is often disastrous,causing severe damages and distortions in the supported structures.It is,therefore,necessary to adequately improve the performance of such soils that they can favorably fulfil the post-construction stability requirements.This can be achieved through chemical stabilization using additives such as lime,cement and fly ash.In this paper,suitability of such additives under various conditions and their mechanisms are reviewed in detail.It is observed that the stabilization process primarily involves hydration,cation exchange,flocculation and pozzolanic reactions.The degree of stabilization is controlled by several factors such as additive type,additive content,soil type,soil mineralogy,curing period,curing temperature,delay in compaction,pH of soil matrix,and molding water content,including presence of nano-silica,organic matter and sulfate compounds.Provision of nano-silica not only improves soil packing but also accelerates the pozzolanic reaction.However,presence of deleterious compounds such as sulfate or organic matter can turn the treated soils unfavorable at times even worser than the unstabilized ones.展开更多
This article provides an overview of several previous studies that investigated the stiffness and strength performance of chemically stabilized roadway materials under winter conditions （freeze-thaw cycling）. The ob...This article provides an overview of several previous studies that investigated the stiffness and strength performance of chemically stabilized roadway materials under winter conditions （freeze-thaw cycling）. The objective of this research was to understand the behavior of different materials stabilized with different type of binders when they were subjected to freeze-thaw cycling. Nine different materials including natural soils （organic soil, clay, silt, sand, and road surface gravel）, reclaimed pavement material, and recycled asphalt pavement stabilized with nine different binders （five different fly ashes, lime, cement, lime kiln dust, cement kiln dust） were discussed. This article investigated how the volume, resilient modulus and unconfined compressive strength of soils/materials stabilized with different binders change in response to freeze-thaw cycling. Overall, the review results indicate that the stiffness and strength of all stabilized materials decrease somewhat with freeze-thaw cycling. However, the reduced strength and stiffness of stabilized materials after freeze-thaw cycling was still higher than that of unstabilized-unfrozen original soils and materials. In addition, materials stabilized with cement kiln dust provided the best performance against freeze-thaw cycling.展开更多
文摘An experimental program was undertaken to study the individual and admixed effects of lime and fly ash on the geotechnical characteristics of expansive soil.Lime and fly ash were added to the expansive soil at 4%-6% and 40%-50% by dry weight of soil,respectively.Testing specimens were determined and examined in chemical composition,grain size distribution,consistency limits,compaction,CBR,free swell and swell capacity.The effect of lime and fly ash addition on reducing the swelling potential of an expansive soil is presented.It is revealed that a change of expansive soil texture takes place when lime and fly ash are mixed with expansive soil.Plastic limit increases by mixing lime and liquid limit decreases by mixing fly ash,which decreases plasticity index.As the amount of lime and fly ash is increased,there are an apparent reduction in maximum dry density,free swell and swelling capacity under 50 kPa pressure,and a corresponding increase in the percentage of coarse particles,optimum moisture content and CBR value.Based on the results,it can be concluded that the expansive soil can be successfully stabilized by lime and fly ash.
基金Project(05YFSYSF00300) supported by the Natural Science Foundation of Tianjin
文摘Through unconfined compressive strength test,influencing factors on compressive strength of solidified inshore saline soil with SH lime-ash,ratio of lime-ash(1-K),quantity of lime-ash,age,degree of compression and salt content were studied.The results show that because inshore saline soil has special engineering characteristic,more influencing factors must be considered compared with ordinary soil for the perfect effect of solidifying.
文摘Volume instability of expansive soils due to moisture fluctuations is often disastrous,causing severe damages and distortions in the supported structures.It is,therefore,necessary to adequately improve the performance of such soils that they can favorably fulfil the post-construction stability requirements.This can be achieved through chemical stabilization using additives such as lime,cement and fly ash.In this paper,suitability of such additives under various conditions and their mechanisms are reviewed in detail.It is observed that the stabilization process primarily involves hydration,cation exchange,flocculation and pozzolanic reactions.The degree of stabilization is controlled by several factors such as additive type,additive content,soil type,soil mineralogy,curing period,curing temperature,delay in compaction,pH of soil matrix,and molding water content,including presence of nano-silica,organic matter and sulfate compounds.Provision of nano-silica not only improves soil packing but also accelerates the pozzolanic reaction.However,presence of deleterious compounds such as sulfate or organic matter can turn the treated soils unfavorable at times even worser than the unstabilized ones.
基金support of research and outreach of recycled materials and industrial byproducts for use in construction
文摘This article provides an overview of several previous studies that investigated the stiffness and strength performance of chemically stabilized roadway materials under winter conditions （freeze-thaw cycling）. The objective of this research was to understand the behavior of different materials stabilized with different type of binders when they were subjected to freeze-thaw cycling. Nine different materials including natural soils （organic soil, clay, silt, sand, and road surface gravel）, reclaimed pavement material, and recycled asphalt pavement stabilized with nine different binders （five different fly ashes, lime, cement, lime kiln dust, cement kiln dust） were discussed. This article investigated how the volume, resilient modulus and unconfined compressive strength of soils/materials stabilized with different binders change in response to freeze-thaw cycling. Overall, the review results indicate that the stiffness and strength of all stabilized materials decrease somewhat with freeze-thaw cycling. However, the reduced strength and stiffness of stabilized materials after freeze-thaw cycling was still higher than that of unstabilized-unfrozen original soils and materials. In addition, materials stabilized with cement kiln dust provided the best performance against freeze-thaw cycling.
