Preliminary Survey on the Crucial Root Causes of Material Waste Generation in Malaysian Construction Industry

Construction waste generation has been perceived as a crucial issue that has critical consequences on the project effectiveness and ecological effect of the construction industry. The key objective of the current research is to identify the root causes of material construction waste generation in Malaysia. A well-structured questionnaire was designed based on the 52 identified root causes of material waste generation. The developed questionnaire was distributed to 35 highly experienced in Malaysian construction industry experts. The collected data was analyzed by the use of mean score analysis. The top identified root causes are poor supervision during the construction stage, lack of efficient site management, last minute changes, cutting uneconomical sizes of materials, and constant design changes during the construction period. The initial findings will aid construction practitioners to focus on these root causes in order to reduce the material construction waste generation at construction sites. Keywords-preliminary survey; material waste; root causes; environment; Malaysia


INTRODUCTION
Construction industry is considered a key part in any nation's socio-economy growth.Nowadays, construction industry is developing rapidly [1][2] but is generally considered environmental unfriendly [3].This industry enhances considerably environmental problems such as exploration of the natural resources, irretrievable conversion of the environment, and increase of contaminants in the atmosphere [4].Construction waste is produced throughout site clearance, material utilization, overabundance acquirement of materials and human errors at construction site.10-30% of the waste starts from construction works [5,6].Therefore, initial identification of the root causes is essential in order to reduce material waste generation rate.

II. CONSTRUCTION WASTE
Material waste can be generated throughout construction works.It may occur in preliminary design stage, during construction and with poor human behavior [7][8][9].Construction waste is considered as any material that is damaged, unnecessary and extra purchased, or noncompliant to specifications [2,10].According to [11,12], annual construction waste generation has been increasing in Malaysia.Construction waste is being created through the entire construction time frame, from the earliest starting point of the outline arranged until the last stage.There are numerous root causes that prompt construction waste generation.It is essential to distinguish those causes in order to control waste generation.According to [1], there are several root causes of construction waste generation such as design, workers, management, procurement, site condition, handling and external factors.It is stated that poor site management is one of the major root causes in producing waste.Absence of awareness or knowledge in construction waste, procurement of materials differing to specification, unsuitable storage causing damage and rework are among the key causes identified in contributing to waste generation rate [13].It has been discovered that waste produced in Malaysian construction projects are mainly initiated by employee and management problems [14].These root causes should be controlled to reduce the quantity of generated waste.There are other aspects that are considered as sources of construction waste such as incomplete information, weak material management, unskilled labor, and damage during transportation [15].The root causes were categorized under common characteristics like material management on site, material handling, transportation and storage and site management and practices in [16].
III. RESEARCH METHODOLOGY This study adopts quantitative technique in order to comprehend the viewpoint of construction experts towards the root causes of construction waste generation in Malaysian construction industry.The exploration of this research is divided into 2 phases.The first phase includes extensive literature review after which 52 root causes contributing to material construction waste generation were identified.In the second phase, a questionnaire was developed.The questionnaire comprises of two parts, demography of the respondents and root causes of waste generation rate in Malaysian construction industry.Each respondent was asked to verify the crucial root causes for the environment of Malaysian construction industry.

IV. DATA COLLECTION AND ANALYSIS
The questionnaire was designed based on a five-point Likert [17] scale ranging from 1 for Disagree to 5 for Strongly Agree.The developed questionnaire was distributed to 35 experts in Malaysian construction industry.The received questionnaires were analysed and reliability test was conducted.The Cronbach's alpha value was 0.970 which indicates a high level of consistency.According to [18,19], if Cronbach's alpha value is higher than 0.7, the inner consistency of data is highly acceptable.Figure 1 indicates the number of respondents and their corresponding working experience.The majority (12 out of 35, 34.3%) of the respondents have 16-20 years of experience in the construction industry.The total percentage of respondents with more than 10 years of experience in the industry is about 88.5%.This shows that the majority of the respondents are eminently experienced and vastly knowledgeable regarding Malaysian construction industry.Respondents' enterprise type

V. RESULTS AND DISCUSSION
The mean value of each root cause of material waste generation is presented in Table I.Result analysis showed that the root causes with the higher mean value for generation of waste in Malaysian construction industry are "supervision during construction stage is poor", "efficient site management is lacking", "last minute changes due to client requirements", "cutting uneconomical sizes of materials", "constant design changes during construction period", "unsuitable tools used during construction", and "unsatisfactory attitude of workers", The ranking of the root causes of construction waste generation is shown in Table II.There are 46 root causes which scored more than 4.00, however for this paper only the top root causes are elaborated.

A. Supervision During Construction Stage is Poor
Supervision and coordination is clearly expected to guarantee great task conveyance.Satisfactory supervision prompts quality employment yet accompanies extra cost for the successful supervision [19][20][21].Good project supervision is imperative as it might give important pointers to different elements that may cause problems [22,23,27].Therefore, poor supervision at site leads to more material waste generation.

B. Lack of Efficient Site Management
Site management should have a work task flow according to the project's needs [24][25][26].Teamwork should be incorporated for an efficient site management plan [27,28].This includes managing scope, issues, risks, communication and the work plan.If the site management is not systematic the work will be faulty and will cause reworks.If basic management is lacking, the construction waste generated will not be coordinated efficiently, thus a huge sum of waste such as concrete, metal, sand, timber will be generated.This root cause is one of the main contributors to construction waste generation.

C. Last Minute Changes due to Client Requirements
Changes in design occuring while construction has begun is one of the root causes of generating waste [23,29,30].Clients should be clear with their vision of the project from the beginning.

D. Cutting Uneconomical Sizes of Materials
Cutting materials into different sizes and uneconomical shapes generates waste [23].When timber or metal are being cut without considering the next usage, the excess becomes waste.This factor is one of the highest regarding the volume of waste in waste production [31,32].

E. Constant Design Changes During Construction Period
Sudden drawing changes can lead to higher waste generation [25,26,33].This is an issue among contractors, designers and clients during design work stage [23,30,31,34].When the design is not confirmed during the initial stage, frequent changes may occur in construction period generating material wastages.This could be avoided if all the parties involved could have frequent productive meetings during the design stage to confirm the design prior to the construction.

F. Unsuitable Tools Used During Construction Stage
Tools used during construction may not be appropriate or suitable [25,27,35] leading to augmented generation of construction waste.

G. Unsatisfactory Attitude of Workers
In a construction site, poor behavior can distress everyone and cause conflicts among workers [36,37].Laziness of workers can cause reworks in the project [26,27].Hence bad attitude may have crucial effects on work, causing workers to become dispirited and unhappy which would cause mistakes to occur more often and output would likely be poor [38].

H. Slow Information Flow Among All Parties Involved in the
Project Causing Redundant Work Communication and effective information flow are a pivotal part in construction procedures [36,39].Having an efficient information flow among all parties can give a focused favorable advantage to a construction project [19,29].Bad information flow will cause redundant work.

I. Improper Material Handling by the Workers
All materials received at site should be unpacked and arranged properly to avoid any damage [23,[31][32][33].If the materials are not handled with care, damage can occur generating construction waste [36,38].

J. Rework due to Miscommunication Among Engineers and Workers
Failure to communicate can ultimately lead to serious accidents at site, project rework, and employee problems [31].When there is miscommunication among the team, rework will occur often and more material waste will be produced.Effective communication is critical for collaborative work [23,32].Clear communication not only reduces rework, it can also significantly increase the efficiency of the construction process [1,34].
K. Lack of Possibility of Ordering Small Quantities of Materials Lack of possibility of ordering small quantities of materials is one of the common causes of construction waste generation [30].Usually, only bulk orders can be ordered from a supplier [7,10,33].There would be a minimum ordering amount to be fulfilled even though the amount required is less than the minimum order.Therefore, material waste such as cement, timber, etc. will occur if there is excess of unused material.

VI. PRELIMINARY SURVEY OUTCOME
While conducting the preliminary survey, the construction practitioners suggested six major root causes which contribute to waste generation of Malaysia construction industry.They are "human mindset of ignorance", "political involvement", "errors during installation", "less usage of prefabricated materials", "breakdown of equipment during concreting work" and "lack of BIM usage for design".Regarding the first, human nature is to be of no concern on the waste and environment and the actions that must be taken.For "political involvement", we should note that there has been a change in recent government, thus, many construction projects have faced design changes, kept on hold or stopped [40], "Errors during installation" occur during improper installation of scaffolding which may cause damage to the materials used [4], "Less usage of prefabricated materials" shows that material wastage compared to conventional construction can be reduced, "Breakdown of equipment during concreting work" may occur during malfunction of concrete pump where the leftover concrete in the pump will turn into waste.Lastly, "lack of BIM (Building Information Modeling) usage" for design purpose shows that BIM can help minimize handling of work from the design stages.

VII. CONCLUSIONS
This research found that construction waste generation is a major issue in the Malaysian construction industry, thus it is crucial to identify the root causes which contribute to construction waste generation in order to minimize the generated waste.After analysis, 46 root causes with mean value more than 4.00 were considered as crucial root causes.The acquired root causes will aid the construction practitioners to curb the construction waste generation from the initial stages of construction.The outcome of this research will not only be valuable in minimizing material waste generation but it will also support cultivating environmental awareness in construction industry of Malaysia.

Fig. 1 .Figure 2
Fig. 1.Respondents' working experience Figure 2 exhibits the respondents' organization/enterprise.Most of the respondents are contractors with 62.9% (22 out of 35).The opinions of contractors are considered important as they are the ones who are stated at the site and have better understanding about the root causes of construction waste generation.Clients' and consultants' inputs are crucial as well

TABLE I .
ROOT CAUSES OF CONSTRUCTION WASTE GENERATION AND THEIR MEAN VALUES