Abstract
Insitu cementitious stabilisation is an economical, environmentally sustainableand socially advantageous means of rehabilitating pavements. With the recentavailability of a wide range of binders and advanced construction equipment,the characterisation of cementitiously stabilised pavement materials hasbecome the focus of further advancement of this technology.Australian practice has moved towards the use of Indirect Diametric Tensile(IDT) methods for the characterisation of these materials. A draft protocol forthe IDT test has been prepared and specifies samples to be compacted bygyratory compactor. This procedure provides for both monotonic and repeatedload testing, which aims to measure the material's strength, modulus andfatigue life.A range of host materials, including a new crushed rock and a reclaimedexisting pavement base course, were assessed when stabilised with a GeneralPurpose cement binder as well as with a slag-lime blended binder. Materialswere assess for their inherent material properties, Unconfined CompressionStrength (UCS), Unconfined Compression modulus, IDT strength and modulusunder both monotonic and repeated load.A number of amendments and refinements to the testing protocol wererecommended. These included the use of minimum binder contents to ensurethe binder was uniformly distributed and to promote heavy binding of thematerials to ensure they behaved elastically. It was also recommended thatsamples be gyratory compacted to a pre-determined sample height to allow aconstant density to be achieved.The variability of the test results was examined. UCS results were found to becomparatively as variable as other researchers had reported. IDT strengthresults contained a similar level of variability, which was considered to beacceptable. Modulus results, both monotonic and repeated load, were found tobe five to ten times more variable than strength results, which is a generallyaccepted trend for modulus testing.Under repeated loading, some challenges with the test protocol wereencountered. The primary challenge was obtaining reliable and repeatablediametrical displacement data for modulus calculation. This was partiallyovercome by the insertion of smooth spacers to prevent the Linear VoltageDisplacement Transformer (LVDTs) becoming caught on the sample sides.The achievement of reliable and repeatable IDT modulus results throughimproved displacement measurements should be the focus of future researchefforts in this area.