| Summary: | ABSTRAK
To reduce the effect of pumping caused by dynamic loading from subgrade of pavement structures on saturated soft day, geotextile filter is placed between subgrade and subbase course. The criteria to select the proper geotextile type for this purpose, so far is assumed to be the same with that for uni-directional filtering. For uni-directional filtering only three parameters are considered, those are grain size of subgrade, permitivity and the opening size of geotextile. From the previous studies, it was reported that the effect of pumping is also influenced by type, thickness and mass per unit area of geotextile, dynamic loading frequency and magnitude. However, there has been no single directed conclusion.
This study was intended to reveal more knowledge in this subject by testing the effect of dynamic loading on speciments of the lower part of pavement structure with several variation of geotextile filters, the frequency and repetition of the dynamic loading. A servopulser testing machine was used for this purpose.
The result show that the spun bonded, thermally bonded non woven geotextile and woven geotextile is not effective jitter for dynamic loading. Only the needle punched non woven geotextile was observed to be effective until 30.000 loading repetition. The Apparent Opening Size of geotextile was found to be not the single parameter determining the filter stability of pavement structure, but thickness and mass per unit area of geotextile was found to be other parameters. Greater loading frequency and repetition give more soil mass and bigger grain size passing through the filters.
Keywords : geotextile, filter and dynamic loading
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