Multi-scale mechanical and acoustic characterization of low noise pavements.

Using data on in situ performance of low noise pavements, three well performing mixtures were selected: SDA 4, SDA 6, and SDA 8. These mixtures and the corresponding mastic (filler + bitumen + additive) were tested for their mechanical and acoustic performance in non-aged and aged states using a multi-scale approach (mm to km). Thereafter, an optimization protocol was applied to these mastics (mm-scale) and promising combinations were implemented at the mixture scale (cm-scale).

Environmental trade-offs for using low-noise pavements: Life cycle assessment with noise considerations.

Noise mitigation is the main advantage of semi-dense asphalt (SDA) pavements compared to traditional pavements such as stone-mastic asphalt (SMA), but noise is not quantitatively considered in traditional life cycle assessment (LCA). This article performs a comprehensive LCA for SMA and SDA including noise considerations. State-of-the-art sound emission and acoustical ageing models were used to determine the road traffic noise.

Functional and environmental performance of plant-produced crumb rubber asphalt mixtures using the dry process.

Incorporating crumb rubber (CR) using the dry process, directly in the asphalt mixture rather than into the bituminous binder requires no plant retrofitting, and therefore is the most practical industrial method for CR incorporation into asphalt mixtures. Nevertheless, very few large scale studies have been conducted. This work uses a holistic approach and reports on the functional and environmental performance of asphalt mixtures with different concentrations of CR fabricated employing the dry process in asphalt plants.

Observation of asphalt binder microstructure with ESEM.

The observation of asphalt binder with the environmental scanning electron microscope (ESEM) has shown the potential to observe asphalt binder microstructure and its evolution with binder aging. A procedure for the induction and identification of the microstructure in asphalt binder was established in this study and included sample preparation and observation parameters. A suitable heat-sampling asphalt binder sample preparation method was determined for the test and several stainless steel and Teflon sample moulds developed, finding that stainless steel was the preferable material.

Effects of green and black tea biocomposites on endogenous synthesis, metabolism and genotoxic effect of carcinogenic N-nitrosodimethylamine.

Aim: To study the modifying effect of green and black tea biocomposites on endogenous synthesis and genotoxic action of the carcinogenic N-nitrosodimethylamine.

Methods: Green and black tea biocomposites were administered to the white inbred rats in vivo. Amidopyrine and sodium nitrite were used as N-nitrosodimethylamine precursors and 4-methylpyrazol as an inhibitor of its metabolism.