Plain concrete pavements were tested using the Accelerated Loading Facility (ALF) at a site near Goulburn, NSW, between 1998 and 2000. Four pavements were tested to assess fatigue performance and five pavement sections to assess erosion performance. The site chosen had a high diurnal temperature changes, in the order of 20 degrees Celsius, which produced significant interaction of loading and slab curl. Slab curl and loading deflection of various slab types were recorded in both the fatigue and erosion trials for the purposes of quantifying the effects of dowels, tied shoulders and thickness, as well as erosion of unbound and bound sub-bases in the erosion trials. Correlation was also made between a loaded two-axle rigid truck and a six-axle semi trailer and the single axle dual-tyred ALF assembly. This paper reports the effects of diurnal temperature changes on slab curl; load and type of load on slab response at different diurnal temperatures, dowels, shoulder and thickness on slab curl and slab response-to-load, and relative erosion of unbound, bound and lean mix concrete sub-bases. It is recommended that: (1) the benefits of tied shoulders need to be retained in pavement design; (2) a minimum slab thickness to reduce curling and the effects of curling on pavement performance be specified for pavements subject to heavy loading; and (3) unbound sub-bases not be used under plain concrete pavements subject to heavy loading. As with all accelerated trials, consideration must be given to long term environmental effects and the possibility of fines moving between the base and sub-base which may change loading stresses arising with slab curl. Draining of this interface is considered essential. (a)
Samenvatting