Rapid industrialization indeveloping the construction sector will encourage the growth in urbanized areasfor countries. For current scenario, there is fast manner growing ofconstruction industry. This is because construction industry will definitelysupport the urbanization since all over anywhere require constructionactivities.Almost all commercialactivities are undertaken in buildings and on highways and rail systems thatrequire concrete and asphalt-bound structures which is comprised of almosttotally aggregate. Aggregate comprises about 65-85% of volume from total structures,the binder (Portland cement in concrete and bitumen in asphalt pavement or tar)and the reinforcing skeletons made of structural steel comprise the remainingpercentage.
But for the different view,there are a lot of problems come out on the raw material’s availability.Continuously explore the natural resources forconcrete production will threaten the condition of the environmenton earth (Logeswaran, 2015). Theextraction of gravel from rivers will bring impact for the ecosystem anddeplete the soil quality (Edmore Kori and Humphrey Mathada, 2012).It is clearly shows that theconstruction industry is one of the major industries contributing to theseenvironmental threats. The amount of the aggregate used as construction materialsfor each year is very surprising. This values more than $70 billion which inturn makes aggregate production one of the most important mining industries inthe world (Yasmin Yusuf, 2014). As the result, the concrete industry faces a serious decline of natural aggregates.It is not uncommon to see so many natural resourcesbeing depleted due to extensive use of the natural resources used in theconstruction industry.
Malaysia is being thelargest producer and exporter of palm oil, which accounting for about 52% of the total world oilsand fats export in the year 2006 (Surnathiet al., 2008).Thus, it is expected that millions tomes of palm oilwaste will be produced annually due to its huge productivity. According to Yap et al.
(2013), there is 0.06 milliontonnes of POFA is produced every year in Malaysiawhich generates the increasing trend for the wastage problem. This made Malaysia has been facing problem indisposing palm oil fuel ash, a by-product of palm oilmill since many years ago. The discharge of this high organic waste will cause negative impact tothe environment.The rapid growth of population hasincreased the demand on the water supply. Typically, water treatment plant willproduce almost hundred thousand tonnes of sludge per year (Bourgeois et al.
,2014). The generated sludge will directly drain into water body or dump forlandfill after dewatering process. Although this is inexpensive to dispose thesludge, but it is not an ideal solution where the sludge may contain possibilityof contaminants from chemical substances during treatment process. This is oneof the challenges to outline the sustainable sludge management strategy withminimal effect on the environment. Due to the huge amounts of constructionand solid waste, government needs toallocate more hectares of landfill for disposal and spends a lot of money fortransporting the waste includes the maintenance purposes.In addition, government also facedproblems when forced to allocate more landfill andalso sustainable management for thedisposal of concrete, one of the construction wastefrom demolition or renovation. Besidesthese, there are limitations that restrain the construction aggregate market which include high risein energy cost, transportation cost, seasonal factor and stringent zoning (PersistenceMarket Research, 2016). Human activities without compromise thesustainable planning and disposal strategies also result in severe damages to the environment especially theclimate change throughoutthe world.
For instance, there are a few ofwildfire incudes flooding,tsunami and drought due to global warming, rising of sea level, depletion ofthe ozone layer which will cause increasing threats of cancer and land loss due to contamination of soil.Therefore, the shortage ofconventional building materials for the construction development should betaken consideration whereas the abundantly available industrial waste productsshould be promoted as the alternative new building materials (Kumar 2002). In order to deal with thedeclination of natural resources and waste disposal problem, the construction industries find ways of substitutingrecycled concrete aggregates for natural aggregate. There are many studiesabout the use of recycled waste in general and more attention has been given to the recycling ofvarious waste streams to produce artificial lightweight aggregates (LWA) andlightweight cellular geopolymer. Since the wastage fiom palm oil andwater treatment plant are not reusedand recycle in any works, so the wastage can be used of artificial aggregate containing POFA as additional binder material to cement.
But yet, there are limitavailable information on the utilization of silt and POFA combination as theaggregates replacement in concrete.