Journal Published Online: 22 December 2016
Volume 45, Issue 1

Laboratory Investigation of a Geosynthetic Reinforced Pavement Under Static and Dynamic Loading

CODEN: JTEVAB

Abstract

Construction of roads in soft soils is often associated with design and construction difficulties due to their compressibility nature and weak strength. Road pavements in such areas when subjected to traffic loading that are static and dynamic in nature experience a rapid deterioration of the base material and progressive permanent surface deformation. Both reduce serviceability, and subsequently, the design life of the pavement. In this study, reinforcement geosynthetics (geogrids and geotextiles) were used as reinforcement inclusions within a granular base underlying a soft subgrade having a California Bearing Ratio less than 2 % in a 1.0 m3 steel test box. Bench scale plate load tests (static and cyclic) were conducted on a 305mm diameter circular steel plate on the two-layer system using a Universal Compression Machine. Static loading was applied at a rate of 1.2mm/min. Dynamic sinusoidal load was superimposed atop a static hold down force of 4kN. The dynamic load was linearly increased with an incremental load of 4kN for every 8 cycles at a frequency of 0.2 Hz. For the tests, settlement failure of the composite system was considered at a deformation of 75mm as prescribed for unpaved roads. The results showed that there was a significant improvement in bearing capacity and reduction in settlement accruing from geosynthetic inclusion as shown by the bearing capacity ratio (BCR) of 1.21, 1.29, and 1.63 for geogrid, geotextile, and geogrid-geotextile combinations, respectively. Additionally, a settlement reduction factor (SRF) of 18 % for geogrid, 23 % for geotextile, and 31 % for the geogrid-geotextile combination resulted. There was also an improvement in extended pavement life as depicted by the traffic benefit ratio (TBR) greater than 1 for all reinforced base layers. Comparing geotextile and geogrid reinforced pavements, the results showed that geosynthetic tensile strength is not the governing performance indicator.

Author Information

Kiptoo, D.
Dept. of Civil Engineering, Univ. Of Cape Town, Cape Town, ZA
Aschrafi, J.
Inst. for Geotechnical Engineering (IGS), Univ. of Stuttgart, Institute for Geotechnical Engineering (IGS), Stuttgart, DE
Kalumba, D.
Dept. of Civil Engineering, Univ. Of Cape Town, Cape Town, ZA
Lehn, J.
Inst. for Geotechnical Engineering (IGS), Univ. of Stuttgart, Institute for Geotechnical Engineering (IGS), Stuttgart, DE
Moormann, C.
Inst. for Geotechnical Engineering (IGS), Univ. of Stuttgart, Institute for Geotechnical Engineering (IGS), Stuttgart, DE
Zannoni, E.
Maccaferri SA Ltd, Johannesburg, ZA
Pages: 9
Price: $25.00
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Stock #: JTE20160170
ISSN: 0090-3973
DOI: 10.1520/JTE20160170