Compaction Trials. Prior to the commencement of earth works the contractor shall construct trial compaction lengths as directed by the Engineer or his Representative. The soils used in the trials shall be those that will be used for the construction of earth fill and the compaction equipment to be used shall be that specified in the contractor’s detailed programme of work and approved by the Engineer or his Representative. The object of these trials is to determine the field moisture content of the material and the relationship between the numbers of compaction.
Compaction Trials. Compaction requirements for Zones 1B, 2 and 4 materials shall be determined by compaction trials to be carried out on the first quantities of fill to be placed in the Works or on a trial section of fill to be constructed specially for the purpose. In all cases, the compaction trials shall demonstrate that the selected method for compaction meets the compaction requirements given below. For fill material for Zone 1B, the trial section shall comprise of four layers of fill, in an area of approximately 500 m2. At least 20 No. in-situ density measurements shall be carried out, each with an associated laboratory compaction test on material taken from the site of each in situ density measurement. At least 3 sets of tests shall be done on each layer. The remaining tests shall be carried out in the bottom layer after the top layer has been compacted and shall be in the vicinity of the locations where the tests on the previous layer were carried out. The mean relative compaction for each set of ten results shall not be less than 98% and not more than one result shall give relative compaction less than 90%. In the case of fill material for Zone 4, the trial section shall comprise a single layer of fill. At least 10 No. in- situ density tests, each with an associated laboratory compaction test, shall be carried out on each layer during the trial. The minimum relative compaction value given by these results shall not be less than 95%. For Zone 2, the trial section shall comprise fill 500mm thick placed in appropriate layers. At least 3 No. in- situ density tests, each with an associated laboratory compaction test, shall be carried out on each layer during the trial. The mean relative compaction value given by these results shall not be less than 98% with no one value dropping below 95%. All test results obtained from compaction trials shall be submitted to the Engineer as the work proceeds.
