Civil Engineering

Harnessing the potential of unconventional materials for a sustainable pavement infrastructure is not new; hence, this research explores the effect of Corn Starch (CS) on the dynamic modulus and fatigue resistance properties of asphalt concrete to serve as a basis for using such materials for asphalt concrete production. An experimental procedure using the Marshal Mix design method was adopted to achieve the representative samples, while the Asphalt Institute model was used to obtain the dynamic modulus and fatigue life parameters for unmodified and modified conditions. Overall the research findings showed that CS improved the strain resistance, dynamic modulus (related to the stiffness of the HMA concrete), and fatigue performance of the asphalt concrete as forecasted because of the binding qualities of the CS. However, the optimum binder modification content to attain maximum values for both parameters was recorded at 5%. Thus, CS has the potential to be an excellent material for improving the strength performance characteristics of asphalt concrete pavements. Background: Good road infrastructure is an essential component of a stable economy. Asphalt concrete is a popular mixture of asphalt or bitumen and aggregates widely used for road construction because of its effective binding properties. Asphalt concrete pavements are being subjected to increasing loads of diverse forms and stresses, and these cause the pavements' useful life to deteriorate considerably. In addition, greenhouse gases (GHG) in the atmosphere are becoming a more significant cause for concern due to the effects of climate change, and embodied carbon from asphalt production and construction is a direct contributor to these emissions, necessitating a reduction in the amount of asphalt used for road construction. The actions of modifying the asphalt paving materials started a long time ago, and hopes were initially sought in earlier experiments of incorporating natural rubber with asphalt in the 1840s to capture the flexible nature of rubber in a longer-lasting paving surface (Sulyman, 2014). Many studies have been conducted to ascertain the effect of different modifiers on asphalt pavement. Polymers are one of the most recommended materials for modifying asphalt concrete in flexible pavements because they have been investigated to significantly improve asphalt properties (Becker, Mendez & Yajaira, 2000). Research and practice have shown that using a polymermodified asphalt binder can significantly improve the fatigue resistance of a Hot Mix Asphalt (HMA) mixture (Asphalt Institute Inc., 2014). Some reasons for utilizing these polymers include; improving the abrasion resistance of asphalt blends, obtaining softer blends at low temperatures and reducing cracking, increasing the strength and stability of the mixture and obtaining stiffer blends at a high temperature and reducing rutting (Lewandoski, 1994). Today, Highway agencies have recognized the benefits of using modified asphalts to reduce the amount and severity of pavement distress and increase service life (Walker,2015). Modified asphalts are often referred to as "polymer-modified asphalts" because polymers are probably the most common type of modification. Modified asphalts may be produced in several ways, and we have some other categories of modifiers that are also essential in asphalt modification. These could be fillers such as crusher fines, fly ash, and carbon black; extenders such as sulfur and lignin; rubbers both natural or synthetic; plastics such as polyethylene, ethylene acrylate, copolymer, and polyvinyl chloride; fiber such as natural asbestos, rock wool, polyester, fiberglass and mineral; oxidants such as manganese salts; antistripping agents such as amines and lime, and various other waste materials (Roberts, 1996).

S: Laboratory investigation of asphalt pavement was carried out in order to ascertain the properties of swell and loss in stability that will occur when under submergence of water between 1 – 5 days. Secondly, the study was to also assess the contribution of polystyrene as a hydro carbon in asphalt pavements when fully submerged during the aforesaid duration. The focus of the study was limited to the Niger Delta Regions of Nigeria owing to the fact that the region constantly experiences excessive rainfalls annually leading to pavement submergence most times. The study was simulated by using hot mix asphalt concretes in the laboratory which is used synonymously with asphalt pavements. The results revealed that the addition of polystyrene to asphalt concrete mixture up to 2.5% reduced swell by 60.