Evaluation of natural additives for warm asphalt mix

Abstract

Asphalt professionals in Cuba, taking as a line of work the sustainability of pavements, are involved in the methods for obtaining warm asphalt mixtures, as a technology to achieve construction efficiency, conservation of resources and the environment without affecting the mechanical performance of hot asphalt mixes. On this basis, two fundamental lines have been investigated to obtain this type of mixtures, using natural resources of existence in the country: the natural zeolites of the Tasajera deposit and the sugar cane wax. The work exposes the availability of resources, as well as the main results derived from the researches carried out. The temperature reductions obtained from experimental research using both additions of natural origin is between 20-30 o C, which allows sustainable results in the production of asphalt mixtures.

Stellar population properties of ETGs in compact groups of galaxies

“…(i) The stellar populations in ETGs belonging to CGs present the same behavior as ETGs in the field following the analysis of the parameters Age, [Z/H] and [α/Fe], indicating that spatial density is not responsible for establishing the stellar content of these systems. We do not confirm the truncation in star formation observed by de La Rosa et al (2007). It is worthy to note that the results shown by de La Rosa et al (2007) are based in a rather small sample composed of 22 ETGs in CGs.…”

“…The ratios are determined using the indices measured from the spectra produced using the model from Vazdekis et al (2010) customised for a set of velocity dispersions (50 -350 km/s). Our correction is in excellent agreement with those applied by de La Rosa et al (2007), which use the models from Vazdekis (1999).…”

“…To remove the effect of the velocity dispersion we applied the broadening correction to the spectral index as defined in de La Rosa et al (2007). The correction is the ratio between the index measured with a given velocity dispersion and the one measured in the rest frame (σ = 0).…”

“…This is often interpreted as an indication that CGs speed up the evolution of galaxies from star forming to quiescent (Tzanavaris et al 2010;Walker et al 2010;Coenda, Muriel & Martínez 2012). Some authors even find evidence of truncation in the star formation for galaxies in CGs (de La Rosa et al 2007). All these observations reinforce the scenario where CGs are gas-poor systems.…”

“…CGs are richer in elliptical galaxies than the field (Lee 2004;Deng, He & Wu 2008). Galaxies in CGs also tend to be older than galaxies in the field (Proctor et al 2004;de La Rosa et al 2007;Plauchu-Frayn et al 2012) but have similar ages when compared to clusters (Proctor et al 2004). This is often interpreted as an indication that CGs speed up the evolution of galaxies from star forming to quiescent (Tzanavaris et al 2010;Walker et al 2010;Coenda, Muriel & Martínez 2012).…”