Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Superpave


Effect of Polymer Additives on Permeability of Asphalt Concrete Mixtures

H.H. Jony; M.M. Hilal; D.S. Helan

Engineering and Technology Journal, 2018, Volume 36, Issue 1, Pages 75-83

The presence of water in the pavement structure causes early deterioration and leads to less pavement durability as a result of loss of bond between aggregate and binder and may causes loss of strength and stability in mixture, The main goal of this study was to investigate the effect of various polymer additives on permeability of asphalt concrete mixture. The surface wearing coarse type IIIA was chosen in this study. Three types of polymer additives were used in this study; (7% Latex Emulsion (LE), 7% Poly Vinyl Acetate with 4% Styrene Butadiene Styrene (PVA + SBS) and 8% Ethylene Diamine (ED)). The results appeared that the permeability average of all mixtures were (27.745, 17.18, 7.773 and 11.409 * 10 -5 cm/s) for (control blend, LE, PVA+SBS and ED) and the percent of decreasing in permeability were (48.52%, 74.547% and 58.312%) for (LE, (PVA + SBS) and ED) respectively.

Fatigue Cracking Performance of Local Superpave Asphalt Concrete Mixtures

Mohammed Y. Fattah; Karim Hadi Ibrahim Al Helo; Zaynab I.Qasim

Engineering and Technology Journal, 2014, Volume 32, Issue 12, Pages 2904-2920

In Iraq, fatigue cracking is considered to be the most important type of distress affecting the performance of asphalt concrete pavements on major state highways. This research describes the results of a laboratory study of the fatigue response of a typical Iraqi asphalt concrete mixes to define the effects of degree of compaction (as measured by air-void content), asphalt content, temperature and aging on this performance parameter. To achieve the objective of this research, the Nottingham flexural fatigue test is considered and Superpave mix design requirements are employed. Test specimens of (400 mm length by 63 mm width and 50 mm height) were sawed from slabs of the mixes prepared to the target air-void contents by rolling wheel compaction. Controlled - procedure. The tests were conducted at temperatures of 10±1°C (50±2°F), 20 ±1°C (68±2°F) and 30±1°C (86±2°F) and at a frequency of loading of 10 Hz. The long term aging experiment employed a full factorial design as well, with three asphalt contents, two aging periods, two air-void contents and three test temperatures for a nominal total of 36 tests were performed. Local material properties, stress level and environmental impacts were considered for this aspect. It was concluded that for strain – controlled testing, an increase in term aging results in a decrease in laboratory fatigue life and a decrease in mix stiffness, and an increase in test temperatures within the range tested results in an increase in laboratory fatigue life and a decrease in mix stiffness. Finally, a series of recommendations are presented for enhancing the fatigue performance of Iraqi pavements including changes to current construction quality assurance procedures.

Rotational Viscosity Prediction Models For Asphalt Cement

Alaa Saadi Abbas

Engineering and Technology Journal, 2011, Volume 29, Issue 14, Pages 2869-2879

It is a great importance to know asphalt cement viscosity in order to perform handling, mixing, application processes and asphalt compaction in highway surfacing.This paper presents the results of rotational viscosity measurement for different asphalt cement sources, grades, and different test temperatures. statistical models were developed to predict the rotational viscosity for any asphalt cement grades that
usually used in pavement work in Iraq and for different test temperatures. in this study six types of asphalt cement have been used. All the asphalt cement are locally available and widely employed for the pavement construction in the Iraq. These asphalt cement are: AC(40-50) from Daurah and Baiji refinery, (AC 60-70) from
Daurah refinery, AC(50-60) from Daurah and Basrah refinery, AC(85-100) from Daurah refinery. Also, this paper shows that no change have been observed in rotational viscosity for asphalt cement blow 100 °C, and it is about 12613 mPa.s.