A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Effect of Remolding on Cement-Stabilized Base Course Blended with Reclaimed Asphalt Pavement
Full-depth reclamation in conjunction with cement stabilization increases the strength and durability of pavement base layers when proper design and construction practices are followed. However, in adverse site conditions, construction challenges can arise. In one instance of particular interest to this research, the practice of adding additional cement, reprocessing, and recompacting an inadequately constructed cement-treated base layer within 1 day of initial compaction was specified. Because the effects of this process on density and unconfined compressive strength (UCS) have not been previously investigated, the purpose of this laboratory research was to quantify the influence of remolding on these properties with and without the addition of extra cement, A total of 12 specimens of recycled base material were compacted at the design cement content of 4 percent to the target maximum dry density of 129.0 pcf, which yielded an average 7-day UCS of 328 psi consistent with Portland Cement Association recommendations for resisting environmental degradation such as frost action. Three specimens were retained as a control group, while the remaining nine were pulverized and sweetened, again in groups of three, with 0, 2, or 4 percent additional cement after 1 day of curing. The average dry density values achieved after remolding with 0, 2, and 4 percent additional cement were 124.7, 123.6, and 126.1 pcf, respectively, corresponding to 96.7, 95.8, and 97.7 percent of the MDD. The average 7-day UCS values of the specimens remolded with 0, 2, and 4 percent additional cement were 161, 274, and 387 psi, respectively, corresponding to 49.2, 83.5, and 118.0 percent of the 7-day UCS of the control specimens. These data suggest that the 7-day UCS values achieved after remolding approach those measured for the control specimens only when approximately 3 percent additional cement is added to the material; this amount of cement corresponds to a 75 percent increase in the total cement content needed for stabilization. At lower cement contents, the remolded material would not be expected to exhibit adequate durability against frost action, and the owner would be mistaken in expecting satisfactory performance based strictly on density testing.
Effect of Remolding on Cement-Stabilized Base Course Blended with Reclaimed Asphalt Pavement
Full-depth reclamation in conjunction with cement stabilization increases the strength and durability of pavement base layers when proper design and construction practices are followed. However, in adverse site conditions, construction challenges can arise. In one instance of particular interest to this research, the practice of adding additional cement, reprocessing, and recompacting an inadequately constructed cement-treated base layer within 1 day of initial compaction was specified. Because the effects of this process on density and unconfined compressive strength (UCS) have not been previously investigated, the purpose of this laboratory research was to quantify the influence of remolding on these properties with and without the addition of extra cement, A total of 12 specimens of recycled base material were compacted at the design cement content of 4 percent to the target maximum dry density of 129.0 pcf, which yielded an average 7-day UCS of 328 psi consistent with Portland Cement Association recommendations for resisting environmental degradation such as frost action. Three specimens were retained as a control group, while the remaining nine were pulverized and sweetened, again in groups of three, with 0, 2, or 4 percent additional cement after 1 day of curing. The average dry density values achieved after remolding with 0, 2, and 4 percent additional cement were 124.7, 123.6, and 126.1 pcf, respectively, corresponding to 96.7, 95.8, and 97.7 percent of the MDD. The average 7-day UCS values of the specimens remolded with 0, 2, and 4 percent additional cement were 161, 274, and 387 psi, respectively, corresponding to 49.2, 83.5, and 118.0 percent of the 7-day UCS of the control specimens. These data suggest that the 7-day UCS values achieved after remolding approach those measured for the control specimens only when approximately 3 percent additional cement is added to the material; this amount of cement corresponds to a 75 percent increase in the total cement content needed for stabilization. At lower cement contents, the remolded material would not be expected to exhibit adequate durability against frost action, and the owner would be mistaken in expecting satisfactory performance based strictly on density testing.
Effect of Remolding on Cement-Stabilized Base Course Blended with Reclaimed Asphalt Pavement
Guthrie, W. S. (author) / Brown, A. V. (author)
14th Conference on Cold Regions Engineering ; 2009 ; Duluth, Minnesota, United States
Cold Regions Engineering 2009 ; 346-355
2009-08-27
Conference paper
Electronic Resource
English
Cement Stabilization of Aggregate Base Material Blended with Reclaimed Asphalt Pavement
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