Based on the result in Table 6, it canbe deduced that there are three (3) types of construction waste that frequentlygenerated at site namely timber, brick & block and concrete, with timber wastebeing the most frequently produced on site.
The result is consistent withprevious research by Whyte (2008) which described the major components ofconstruction waste generated are wood, concrete and bricks.The reasonfor highest timber waste could be because of timber is widely used in theconstruction industry as formwork. Formwork is used as a temporary supportespecially for concreting work and once the building completed this materialwill be disposed.
Nature of timber that easy to rot also becomes one of thereasons why the timber is the highest rank in the production of waste. It canbe proofed by Lachimpadi, Pereira, Taha, &Mokhtar (2012) in their study which stated timber is the largest quantityof construction waste where timber will be used as a temporary support to allconcreting work especially for projects using traditional method. Besides, thelifespan of timber for reuse depends on the quality of the product used inconstruction site.Brick andblock are the second highest waste generated on site. The result is similarwith Ahmad et al. (2014) who also found that brick waste producedthe second highest at construction site.
The high production of brick & blockwaste could be because a lot of construction work is using brick especially forwall and cutting the brick to a desired length to form a perfect wall has producedthe waste. Moreover, local unloading methods play animportant part in the generation of brick waste. Once the materials are brokenor damaged, the brick and block could not be used for construction workanymore.
Thisis supported by previous study which described the cause of brick wastegeneration are cutting and improper unloading (Bossink & Brouwers, 1996; Whyte,2008). Concretewaste placed in the top three of waste generated on site. This appears to be similarwith Lachimpadi et al., (2012) which mentions concrete and aggregate are thelargest waste produced at 60%. The result also similar in those Chochran, Townsend, Reinhart, &Heck (2007) that showsthe highest composition of waste for residential projects are concrete (52%). The cause of the generation of concrete wasteas explored by Poon et al., (2004) found that the concrete wastage inconstruction is mainly due to the disparity between the quantities of concreteordered and that required, mostly in the case of ready mix concrete supply.
Itis also due to poor planning by the contractors on the amount of concreterequired. Additionally,this research identifies the three types of waste that rarely produced at sitenamely steel, sand & aggregates and finishes. According to the rankinglist, steel is ranked as the fourth. This is followed by sand & aggregates asthe fifth and lastly finishes.
Yet, this result differs from those Lachimpadiet al., (2012) which described sand & aggregates are the largest wasteproduced and steel took place the third highest in the ranking. The differencein this research finding could be as the result of the fact that Lachimpadi etal., (2012) focuses on high-rise buildings but this research has not focus onany specific type of projects.
Hence, the researcher concludes thatconstruction waste composition strongly depends on the type of projectsinvestigated. On the other hand, finishes produce the least amount of waste at1% which is similar to the result of this research. This could be due to theleftover pieces after construction project has completed (Nagapan et al., 2011).