Prediction of Subgrade CBR using FWD for Thin Bituminous Pavements

Gary W. Chai ； Shanty Argadiba ； Greg Stephenson ； Inga Condric ； Erwin Y. Oh ； Sittam P. Manoharan

《International Journal of Pavement Research and Technology》 6卷4期 (2013/07) Pp. 280-286

https://doi.org/10.6135/ijprt.org.tw/2013.6(4).280

並列摘要

Deflection based models developed by Jameson, Roberts et al and Queensland Department of Transportation and Main Roads are commonly used for predicting the subgrade CBR of asphalt pavements. The models utilise Falling Weight Deflectometer (FWD) deflection D900 recorded at 900 mm from the centre of the loading plate. The principal aim of the study is to enhance the prediction of the in-situ subgrade CBR using FWD for granular pavements with thin bituminous layers. The scope of the study included the comparison of subgrade CBR predictions from the three deflection based models and the predictions were verified using the in-situ CBR values derived from Dynamic Cone Penetrometer (DCP) from eleven pavement test sites. The study shows that the three models over predict the subgrade CBR because the deflections recorded at sensor D900 are consistently small. It is observed the impact load has little influence on the deflection at D900 for pavements with asphalt layer less than 50 mm. The inherent non-linearity behaviour of the thin pavement structure is also the reason for the discrepancies in the predictions. Consequently, a new predictive model is developed utilising the FWD deflection D450 observed at 450 mm from the impact load.

並列關鍵字

Deflection based model ； Falling Weight Deflectometer ； Non-linearity of pavements ； Subgrade CBR

參考文獻

Rahim, A. and George, K.P. (2003). Falling Weight Deflectometer for Estimating Subgrade Elastic Moduli, Journal of Transportation Engineering, ASCE, 129(1), pp. 100-107.

Nazzal, M.D. and Mohammad, L.N. (2010). Estimation of Resilient Modulus of Subgrade Soils Using Falling Weight Deflectometer, Transportation Research Record, No. 2186, pp. 1-10.

Queensland Department of Main Roads (1993). Pavement Rehabilitation Manual, Brisbane, Queensland, Australia.

Austroads (2008). Technical Basis of the Austroads Design Procedures for Flexible Overlays on Flexible Pavements, Austroads Incorporated, Sydney, New South Wales, Australia.

Brisbane City Council (2011). Pavement Rehabilitation Design Manual, Brisbane, Queensland, Australia.