A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Accelerated Loading Evaluation of Subbase Layers in Pavement Performance
This report documents the research efforts conducted at the Louisiana Transportation Research Center (LTRC) regarding chemical stabilization of the naturally wet and problematic clayey soils typically found as subgrade in south Louisiana and provides detailed information on experiment design, instrumentation, and field and laboratory tests. The objectives of the study included the exploration and development of a methodology to build reliable and conservatively achievable subgrade layers, stabilized with cementitious agents at various field moisture contents so that a treated subgrade layer would not only provide a working table for pavement construction, but could also function as a pavement subbase layer that contributes to the overall pavement structural capacity. Three additives were studied throughout this research: cement, lime, and lime-fly ash. Testing included moisture density evaluations, various additive percentages, various molding moistures and curing times, tube suction testing, resilient modulus and permanent deformation, Eades and Grim tests, and Accelerated Loading Facility (ALF) tests on similar full-scale pavement sections with cement-stabilized and lime-treated subgrades with the magnitude of the ALF loads kept at 9,750 lb. for the first 200,000 repetitions then increased in incremental intervals of 2,300 lb. The laboratory and field research confirmed that among subbase treatments evaluated, cement stabilized soil provided the best performance followed by lime-treated soil. Field and laboratory results also indicated that treating clays with lime and silts with cement will create stronger foundations for pavement structure, because when the appropriate additive and amount is added, the treatment modifies the soil to create consistent, drier layers with improved strength and stiffness and reduced moisture sensitivity as compared to the raw natural soil. A life cycle cost analysis based on the field test results of this study revealed that using a 12-inches cement stabilized soil subbase in lieu of a lime-treated working table layer will create a 37 percent annualized cost savings for low-volume and 31 percent cost savings for high-volume pavement structures in Louisiana. The primary recommendation emphasized the expanded use of treated subgrade layers with target strengths applied to all subgrades susceptible to moisture intrusion in Louisiana rather than optional, working table, subgrade treatment. Treatment alternatives should be based on a benefit cost analysis.
Accelerated Loading Evaluation of Subbase Layers in Pavement Performance
This report documents the research efforts conducted at the Louisiana Transportation Research Center (LTRC) regarding chemical stabilization of the naturally wet and problematic clayey soils typically found as subgrade in south Louisiana and provides detailed information on experiment design, instrumentation, and field and laboratory tests. The objectives of the study included the exploration and development of a methodology to build reliable and conservatively achievable subgrade layers, stabilized with cementitious agents at various field moisture contents so that a treated subgrade layer would not only provide a working table for pavement construction, but could also function as a pavement subbase layer that contributes to the overall pavement structural capacity. Three additives were studied throughout this research: cement, lime, and lime-fly ash. Testing included moisture density evaluations, various additive percentages, various molding moistures and curing times, tube suction testing, resilient modulus and permanent deformation, Eades and Grim tests, and Accelerated Loading Facility (ALF) tests on similar full-scale pavement sections with cement-stabilized and lime-treated subgrades with the magnitude of the ALF loads kept at 9,750 lb. for the first 200,000 repetitions then increased in incremental intervals of 2,300 lb. The laboratory and field research confirmed that among subbase treatments evaluated, cement stabilized soil provided the best performance followed by lime-treated soil. Field and laboratory results also indicated that treating clays with lime and silts with cement will create stronger foundations for pavement structure, because when the appropriate additive and amount is added, the treatment modifies the soil to create consistent, drier layers with improved strength and stiffness and reduced moisture sensitivity as compared to the raw natural soil. A life cycle cost analysis based on the field test results of this study revealed that using a 12-inches cement stabilized soil subbase in lieu of a lime-treated working table layer will create a 37 percent annualized cost savings for low-volume and 31 percent cost savings for high-volume pavement structures in Louisiana. The primary recommendation emphasized the expanded use of treated subgrade layers with target strengths applied to all subgrades susceptible to moisture intrusion in Louisiana rather than optional, working table, subgrade treatment. Treatment alternatives should be based on a benefit cost analysis.
Accelerated Loading Evaluation of Subbase Layers in Pavement Performance
G. Gautreau (author) / Z. Zhang (author) / Z. Wu (author)
2010
160 pages
Report
No indication
English