Investigating the use of reclaimed asphalt along foundry sand in making pavers.
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Ideally, today there is an increase in reclaimed asphalt produced during construction of roads and this material has been mishandled with other waste (George B, 2013). To the present day, there are many roads being constructed in Uganda with an example of the reconstruction of Kinawataka road, Nakawa Division, Eastern Kampala. The construction and rehabilitation of these roads involves removal of aged asphalt and surfacing it with new hot mix asphalt (HMA). This has generally increased the production of Reclaimed Asphalt Pavement (RAP). During the construction and resurfacing of roads, reclaimed asphalt pavement is removed and, in many scenarios, poorly disposed, dumped in the environment ending up with other waste and in landfills. In return, this has contributed to environmental degradation. According to (Mena, 2019) RAP contains volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and heavy metals such as metals lead and chromium and this raises concerns regarding the pollutants from RAP both on people’s health and the environment. In addition, as water gets in contact with reclaimed asphalt materials, pollutants are washed off from this material and it ends up polluting both water sources and soils (Mena, 2019). According to Abdo 2016, RAP has been reused by Americans in hot mix asphalt plants. In fact, when properly crushed and screened, RAP consists of high-quality, well graded aggregates coated by asphalt cement. Recycling asphalt means reduced expenses in quarrying more aggregate materials. This reduction in quarrying means less energy and costs in production, processing and transporting the aggregate materials. As a result, the leveraging recycled asphalt provides significant cost and environmental benefits. During the 2016 construction season, more than 76.9 million tons of RAP and nearly 1.4 million tons of recycled asphalt shingles (RAS) were put to use in new pavements in the United States, saving taxpayers more than $2.1 billion. Also, more than 30 percent of all asphalt pavement mixture produced in the country that year was made using warm-mix asphalt (WMA) technologies. (Abdo, 2016) Also other countries like Germany and Netherlands have also used RAP for the recycling purposes whereas part of it has been dumped in landfills (Shunyashree et al., 2013) In Uganda, the Ministry of Works and Transport realized the need to reuse asphalt pavement by recycling road material in order to reduce the cost of road repairs in Uganda. According to a report by the Ministry of Works and Transport in 2009, Eng. Moses Odongo, the Chief Materials Engineer then quoted that the recycling of pavement asphalt would reduce the cost of road construction by 30 percent. He also noted that it could also improve the lifespan of the roads constructed in Uganda. This decision came as result of a study conducted by a British consultancy, Transport Research Laboratory. (Turyatemba, 2009) Studies have also been conducted on the use of RAP in concrete. In many studies, RAP has been used as a partial replacement of coarse aggregates. However, bigger percentage replacements of RAP have shown some compromised properties such as strength where by compressive strength, split tensile strength and flexural strength of concrete have reduced (Berry et al., 2013) According to (Tia et al., 2012), RAP has been reused to substitute natural aggregates and it didn’t meet therequired standard at higher percentage replacements. However also from previous studies, a notable increase in compressive strength, after replacing the fine aggregates with certain percentage of foundry sand waste in concrete mixes. (Jadhav, etal. 2017) This therefore provides the basis for addressing the compromised strength in RAP concrete mixes as well as the design of pavers. Pavers are modern day solution for less cost outdoor application and used in various places. In this study, we intend utilize RAP (Waste) and foundry sand waste as paver mix ingredients to improve on the strength properties of paver blocks, reduce on and reducing environmental impact of RAP.