Quality and durability of warm rubberized asphalt cement in Ontario, Canada

H Xu, A McIntyre, T Adhikari… - Transportation …, 2013 - journals.sagepub.com
H Xu, A McIntyre, T Adhikari, SAM Hesp, P Marks, S Tabib
Transportation research record, 2013journals.sagepub.com
This paper documents and discusses an investigation of performance-based testing of
asphalt cement (AC), AC modified with warm-mix technology additives (warm AC),
rubberized asphalt cement (RAC), and warm RAC. A number of control, warm, and RAC
binders from Ontario, Canada, construction contracts were investigated for their compliance
with conventional Superpave® as well as additional specification criteria. It was found that
all samples passed the Superpave requirements but only one satisfied the additional …
This paper documents and discusses an investigation of performance-based testing of asphalt cement (AC), AC modified with warm-mix technology additives (warm AC), rubberized asphalt cement (RAC), and warm RAC. A number of control, warm, and RAC binders from Ontario, Canada, construction contracts were investigated for their compliance with conventional Superpave® as well as additional specification criteria. It was found that all samples passed the Superpave requirements but only one satisfied the additional Ontario criteria. One warm AC and two field-blended RAC samples showed high levels of physical hardening, which can lead to early cracking. The warm AC lost 8°C when stored isothermally for 3 days at low temperatures according to Ontario's extended bending beam rheometer protocol (LS-308). The two RAC samples lost 10°C and 12°C following the same conditioning. Many of the investigated samples showed deficient strain tolerance as measured in Ontario's double-edge-notched tension test (LS-299). In an effort to formulate warm RAC with improved properties, a number of compositions were prepared with soft Cold Lake AC and a small quantity of naphthenic oil. These binders showed little chemical and physical hardening and reasonable critical crack tip opening displacements. Strain tolerance was much improved by coblending with a high vinyl-type styrene–butadiene–styrene polymer and a small amount of sulfur. The Ministry of Transportation of Ontario is interested in using the developed formulations in future pavement trials with expected improvements in pavement performance.
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