Browsing by Author "Bambarandage, AR"

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item: Conference-Full-text
Assessment of laboratory and field compaction of dense graded aggregate bases (dgab)
(Springer, 2021) Bambarandage, AR; Jayantha, WRAN; Mampearachchi, WK; Pasindu, HR; Bandara, S; Mampearachchi, WK; Fwa, TF
Dense Graded Aggregate Base (DGAB) construction is a major contributing component in flexible pavement construction in terms of pavement structural capacity and the project cost. However, the production processes related to DGAB construction impose more significant financial, environmental, and social concerns, which stresses the effective compaction in DGAB construction. DGAB compaction process is controlled by three governing factors: moisture content (MC), compaction effort, and layer thickness, where compaction effort can be minimized when field compaction takes place at MC levels closer to the estimated Optimum Moisture Content (OMC). Hence, the relationship among maximum dry density (MDD), OMC, and compaction effort should be well established for a given layer thickness in such a laboratory method that best interprets the field practice. Information on the current industry compaction practices was gathered by conducting a questionnaire survey. Simultaneously, laboratory and field tests were carried out to compare the compaction behavior of DGAB at different MCs and energy levels. Moisture density plots of different laboratory and field compaction tests were compared to determine the most suitable laboratory compaction method to simulate the field compaction of DGAB. The study revealed that the vibratory hammer test resulted in the highestMDDand the lowestOMC,wheremoisture-density curves of the field compaction tests were approaching the vibratory hammer test curve with the increase of compaction effort, emphasizing that the vibratory hammer test best simulates field compaction, when compared to other laboratory impact compaction tests.
item: Conference-Abstract
Energy optimization in compaction of unbound material in road construction
(Department of Civil Engineering, University of Moratuwa., 2015-08) Bambarandage, AR; Mampearachchi, WK; Pasindu, HR
Compaction of Unbound Material in road construction projects, plays one of major role, as it directly contributes to project cost, quality, time and natural environment. Compaction effort is optimized significant amount in soil compaction according to its moisture content. But unfortunately this is not applied to Aggregate Base Course (ABC) compaction in most cases. Water is used as lubricant in traditional practice of macadam base construction & Optimum Moisture content (OMC) concept is not applicable there as it compacts until fines come out with water. Based on that practice, ABC is compacted at high moisture level disregarding compacting effort. In order to achieve the optimum energy level, the relationship between OMC, Maximum dry density (MDD)& Compaction effort (Compaction Energy) should be identified. Understanding of the importance of this concept is a question in present Sri Lankan context. Questionnaire survey was done to collect information of current compaction practice, which are the compaction effort& moisture levels they compact in order to achieve the compaction. Lab and field studies were done to observe the compaction behavior of ABC at different moisture conditions &energy levels. The lab study was performed at four difference energy levels(Standard proctor, Modified proctor, Standard mould with 52 blows & Modified mould with 25 blows), while field was done at six different energy levels (2,4,6,8,10, & 12 roller passes by 11 ton single drum vibratory roller) & at five different moisture levels. Furthermore sieve analysis tests were done after compaction at some selected locations in order to compare the variation with its initial gradation. By analyzing questionnaire survey results, it is reviled that ABC compaction is done at higher moisture levels. Based on the field trial results it is observed that higher compaction effort is ineffective, when compacts at moisture level which is not closed its OMC. Furthermore, it shows that dry unit weight is increased rapidly with lesser no. of roller passes, when it has moisture content lower than the OMC. Finally dry densities are reached to constant value after higher no. of roller passes in all range of moisture levels. It can be concluded that selection of compaction effort mainly depends on it moisture content. But felid in charge officers are trying get required compaction only at higher MC. Therefore ineffective compaction procedures should be brought to end by convincing felid officers. Thus appropriate compaction effort should be identified after testing it's moisture content prior to compaction, in order to achieve cost effective, better quality, timely completion & environment friendly Job.
item: Thesis-Full-text
Evaluation of laboratory and field compaction of dense graded aggregate base
Bambarandage, AR; Mampearachchi, WK
The optimum compaction is required to provide an effective path to enter energy into unbound material under its Optimum Moisture Content (OMC). To achieve the optimum energy level, the relationship between OMC, Maximum Dry Density (MDD) and Compaction Effort need to be identified at field conditions. But it is difficult to conduct in field scenario and therefore those condition are simulated at laboratory condition to find above parameters. However understanding of the importance of this relationship is a question in local context. The information of current compaction practices were gathered by conducting questionnaire survey, while laboratory and field studies were carried out to compare compaction behavior of Dense Graded Aggregate Base (DGAB) at different Moisture Contents (MC) and energy levels. Few number of impact compaction tests and vibratory hammer compaction test were conducted to compare with the field trial test results. The results of field trial study revealed that the higher compaction effort is needed, when compacting at moisture levels which is deviated from OMC. In addition to that Dry Density (DD) is rapidly increased when lesser number of roller passes are applied at MC which is closed OMC. The comparison of field and laboratory test results shows that the vibratory hammer test is suitable to obtain OMC and MDD for field compaction. Although compaction effort can be minimized when it compacts at MC close its OMC, common practice is achieving the required density at higher MC by applying an ineffective compaction effort while leading to segregate the DGAB layer. Therefore appropriate compaction effort should be identified prior to compaction for relevant MC in order to achieve an effective compaction.