Browsing by Author "Shankar, A.U.R."

Now showing 1 - 3 of 3

Evaluation of properties of porous friction course mixes for different gyration levels
(2009) Suresha, S.N.; George, V.; Shankar, A.U.R.
Porous frictions courses (PFCs) are characterized by high percent air voids content, and are widely used as pavement surface drainage layers. This paper presents details on the laboratory investigation performed on evaluation of properties of PFC mixes using the Superpave gyratory compactor. It also, provides a brief review of the latest specifications related to standard practices for mix design and the uses of these mixes adopted by various agencies. Major differences were observed in the design gyrations (Ndesign) and the design aggregate gradations. In this study, six gradations (G) were investigated with binder contents (BCs) ranging between 4.0 and 5.0% by mass of the total mix, for various gyration levels (N). The effect of N, G, and BC on the volumetric properties, unaged abrasion loss, permeability, and the permanent deformation characteristics of PFC mixes were investigated. The experimental results were statistically analyzed to identify the major influencing factors and their significance. © 2009 ASCE.
Performance of Concrete Mix with Secondary Aluminium Dross as a Partial Replacement for Portland Pozzolana Cement
(2019) Panditharadhya, B.J.; Mulangi, R.H.; Shankar, A.U.R.; Amulya, S.
The safety to our ecosystem can be assured by making use of many industrial wastes in a sustainable manner. Recycling and reutilisation of industrial waste and by-products is of high importance in cement and concrete industry. In view of rapid infrastructure growth, there is an emerging need for development of cementitious materials or fillers either to replace cement or fine aggregate for stable growth. One of such industrial wastes is secondary aluminium dross. In this paper, an attempt has been made to study the mechanical properties of concrete incorporated with secondary aluminium dross. Portland pozzolana cement has been partially replaced by secondary aluminium dross in various proportions like 5, 10, 15, and 20% to study the mechanical properties such as compressive strength, split tensile strength, flexural strength, water absorption. It is observed that up to 15% replacement of cement by secondary aluminium dross is giving better results comparable with the conventional concrete. Also, the increase in initial setting time is observed with increase in percentage replacement of aluminium dross in the concrete which can make it preferable in case of hot weather conditions wherein the concreting for the roads has to be done in an open environment. From the overall study, it can be concluded that the concrete incorporated with secondary aluminium dross can be used for making pavement quality concrete that can sustain low traffic volume or it can be considered for rural roads. � 2019 American Society of Civil Engineers.
Stone matrix asphalt using aggregates modified with waste plastics
(2014) Sarang, G.; Lekha, B.M.; Shankar, A.U.R.
Stone matrix asphalt (SMA) is a gap-graded asphalt mixture performing better than conventional dense-graded mixtures. It contains a high concentration of coarse aggregates (forming stone-on-stone contact between them) and high asphalt content. The coarse aggregate skeleton results in better load distribution and the high asphalt content adds durability to the mixture. Due to the high mastic (filler and asphalt) content, there is possibility of drain down during various stages in construction. SMA mix should be prepared with a suitable stabilizing additive to prevent the drain down of mastic material from the mixture. In this study, SMA mixtures are prepared in a Super pave Gyratory Compactor (SGC) with shredded waste plastics, which are mixed with aggregates prior to the addition of Viscosity Graded (VG) - 30 asphalt. Mixtures are prepared with asphalt contents of 5.0 to 7.0 per cent (by weight of aggregates) and stabilizer contents of 0, 4, 8, 12 and 16 per cent (by weight of asphalt). Volumetric and Marshall properties, tensile strength, and moisture susceptibility characteristics are determined. From the laboratory studies, it is observed that addition of waste plastics in shredded form can be used instead of stabilizers by controlling the drain down and enhancing the performance. � 2014 American Society of Civil Engineers.