The research aims to study the causes and magnitude of wastage of construction materials on construction projects sites in Jordan. To achieve the research aim, the researcher had prepared a questionnaire form included questions about the causes of wastage and the estimated percentages of wastage of ten most popular kinds of materials used on construction sites in Jordan. Prior to the final formulation of the questionnaire form, a pilot survey was conducted. The form was revised in accordance with the feedback received. The number of causes adopted was 60 distributed on the six major categories. The form was distributed to 240 participants (clients, contractors, and consultants). The study revealed that the most important causes of wastage of materials on construction sites in Jordan are frequent design and client’s changes; rework due to workers mistakes; poor contract documents; wrong and lack of storage of materials; poor strategy for waste minimization; shortage and lack of experience of skilled workers; poor site conditions; damage during transportation; theft and vandalism; and mistakes in quantity surveying and over allowance. In addition the study concluded that the percentage of wastage materials is accounted for by values between 15% and 21% on Jordanian construction sites.
The objective of the research is to identify the major causes of material waste on construction sites in Jordan based on the opinion of contractors, consultants, and owners also to assess the quantities of wastage in main building materials used in the Jordanian construction sites and making comparison with the other countries.
Jordan is considered one of the most stabled countries in the Middle East, attracting considerable amounts of investments from surrounding countries.
The construction sector has been one of the most active sectors of the Jordanian economy lately. Construction sector accounted for 4.4% of the Gross Domestic Product (GDP) on average over the period 2008–2010. The sector has grown at a Compound Annual Growth Rate (CAGR) of 13.7% during the same period. Credit to the construction sector has also expanded by a CAGR of 20.5%, with the highest growth rates of 34.3% and 24.4% registered for 2009 and 2010, respectively [
Construction materials costs are going through a period of price increase for almost all variety of construction materials. In a study carried out by the Ministry of Housing and Reconstruction in Jordan [
Many authors defined the term of wastage. Construction waste as defined by Ekanayake and Ofori [
Building material wastage can also be defined as the difference between the value of materials delivered and accepted on site and those properly used as specified and accurately measured in the work after deducting the cost saving of substituted materials transferred elsewhere in which unnecessary cost and time may be increased by the material wastage [
Keal [
On the other hand, Koskela [
There are many ways through which causes of wastage can be identified. Chandler [
E. Skoyle and J. Skoyle [
Bossink and Brouwers [
Waste production on construction sites is often due to inadequate storage and protection, poor or multiple handling, poor site control, overordering of material, bad stock control, lack of training, and damage to material during delivery [
Muhwezi et al. [
For the purpose of achieving objectives, a questionnaire was adopted as the major source of data. Designing and preparing the form used was based on the theoretical study of the subject matter including the resources, periodicals, and literatures in addition to face-to-face interviews with engineers representing the main parties involved in the construction process.
During the theoretical study, more than 100 causes of wastage were collected and distributed on six categories. Prior to the final formulation of the form, a pilot survey was conducted. The main purpose was to eliminate the less important questions and to check the clarity and feasibility assurance. The pilot study was carried out through 10 engineers with experience of more than 20 years.
The form was revised in accordance with the feedback received. The final number of causes adopted was 60 causes distributed on the six major groups (10 causes for each group). These are as follows. Group 1: design and contract documents; Group 2: site management; Group 3: procurements; Group 4: storage and handling of materials; Group 5: workers and supervision; Group 6: site conditions and external factors.
Also the form included the perception of the respondents about the estimated percentage for each type of materials selected. The respondents were requested, depending on their previous experience in implementing construction projects, to score their opinions on percentage of construction materials wastage as follows: 0–10%, 11–20%, 21–30%, 31–40%, and 41–50%. The wastage percentage would cover all stages from design through purchasing, transportation, storage, and putting in place. The kinds of materials selected are concrete, steel reinforcements, concrete blocks, cement, sand, ceramic tiles, aggregates, facing stones, timber for formworks, and PVC water pipes.
The forms were distributed to a wide range of engineering staff representing parties involved in the construction process (clients, consultants, and contractors). Number of sets distributed and received is shown in Table
Number of questionnaire sets.
Clients | Consultants | Contractors | Total | |
---|---|---|---|---|
Number distributed | 80 | 80 | 80 | 240 |
Number received | 53 | 57 | 50 | 160 |
Response rate | 66% | 71% | 63% | 67% |
For the analysis of results, 50 forms for each class of respondents were selected to simplify the analysis. The selection was made randomly.
Descriptive and frequency statistical analysis techniques were used to analyze the data collected in the survey. However, an advanced and accurate method is necessary to analyze the data in a systematic, fast, and reliable way. For this purpose, the computer software Statistical Package for Social Science (SPSS 16) and MS Excel were selected.
The data collected from the survey were analyzed using the frequency and severity index method [
According to Assaf and Al-Hejji [
Similarly, a formula as shown in (
The ranking of participant’s responses to the most important 25 causes is shown in Table
Ranking of causes of wastage.
Cause of wastage |
F.I | S.I | I.I | Rank |
---|---|---|---|---|
Frequent design and client’s changes | 74.21 | 74.84 | 55.54 | 1 |
Rework due to workers mistakes | 73.56 | 74.33 | 54.68 | 2 |
Poor contract documents | 72.63 | 72.15 | 52.40 | 3 |
Wrong and lack of storage of materials | 71.84 | 70.65 | 50.75 | 4 |
Poor strategy for waste minimization | 70.01 | 70.23 | 49.17 | 5 |
Shortage and lack of experience of skilled workers | 69.66 | 69.69 | 48.55 | 6 |
Poor site conditions | 70.01 | 68.52 | 47.97 | 7 |
Damage during transportation | 69.92 | 67.53 | 47.22 | 8 |
Theft and vandalism | 68.50 | 68.35 | 46.82 | 9 |
Mistakes in quantity surveying and overallowance | 68.11 | 67.25 | 45.80 | 10 |
Poor quality and nonavailability of equipment | 67.79 | 66.34 | 44.97 | 11 |
Weather conditions | 68.02 | 65.89 | 44.82 | 12 |
Waste resulting from poor packaging | 67.59 | 65.31 | 44.14 | 13 |
Leftover material on site | 66.15 | 66.02 | 43.67 | 14 |
Wrong handling of materials | 65.13 | 65.42 | 42.61 | 15 |
Poor quality of materials | 64.25 | 65.12 | 41.84 | 16 |
Ordering errors | 63.70 | 65.32 | 41.61 | 17 |
Purchasing materials not complying with specifications | 63.01 | 64.26 | 40.49 | 18 |
Supply in loose form | 61.98 | 65.06 | 40.32 | 19 |
Complicated design | 61.88 | 64.39 | 39.84 | 20 |
Damage caused by workers due to lack of experience | 60.25 | 64.23 | 38.70 | 21 |
Long project duration | 58.96 | 63.48 | 37.43 | 22 |
Unnecessary material handling | 58.46 | 62.34 | 36.44 | 23 |
Change in material prices | 57.44 | 62.18 | 35.72 | 24 |
Interaction between various specialists | 56.31 | 55.98 | 31.52 | 25 |
Table
Results of the survey, percentages of wastage of materials.
Material |
Percentages of wastage of materials | Mean | ||||
---|---|---|---|---|---|---|
0–10% | 11–20% | 21–30% | 31–40% | 41–50% | ||
Sand | 35 | 44 | 36 | 22 | 13 | 20.98 |
Aggregate | 40 | 45 | 27 | 21 | 17 | 20.70 |
PVC water pipes | 48 | 38 | 29 | 22 | 13 | 19.61 |
Timber for formworks | 44 | 40 | 35 | 20 | 10 | 19.49 |
Cement | 48 | 46 | 28 | 19 | 9 | 18.34 |
Concrete block | 55 | 44 | 30 | 12 | 9 | 17.05 |
Steel reinforcement | 56 | 42 | 30 | 16 | 6 | 16.91 |
Concrete | 60 | 40 | 27 | 14 | 9 | 16.76 |
Ceramic tiles | 60 | 49 | 22 | 15 | 4 | 15.57 |
Facing stones | 68 | 35 | 30 | 15 | 2 | 15.14 |
The questionnaire of this study considered 60 factors which cause waste of materials in construction projects in Jordan. The results shown in Table
Table
The “
The “
The study revealed that the “
Table
The “
Table
F.I, S.I, and I.I ranking of the groups of factors.
Group |
F.I | S.I | I.I | Rank |
---|---|---|---|---|
G1: factors related to design and contract documents | 66.74 | 66.36 | 44.29 | 1 |
G5: factors related to workers and supervision | 65.31 | 62.75 | 40.98 | 2 |
G4: factors related to storage and materials handling | 57.09 | 58.39 | 33.33 | 3 |
G3: factors related to procurement | 55.35 | 53.33 | 29.52 | 4 |
G6: factors related to site conditions and external factors | 52.69 | 50.48 | 26.60 | 5 |
G2: factors related to site management | 49.22 | 48.66 | 23.95 | 6 |
The study concluded that construction wastage materials are accounted for by values between 15 and 21% in Jordanian construction sites.
These figures seem to be high if compared with results obtained from construction sites in developed countries like USA and UK. The figures in these two countries are accounted to be 3.5 to 10% [
There are many other research works studied about the reasons for wastage of each type of the abovementioned materials [
Improving the standard of the contract documents to avoid wastage resulting from poor documents, design changes, and changes of the client’s requirements and avoiding design errors should be done. The contractors should play important role in reducing the waste during the construction process. This would be through implementing good strategies for resource management, waste minimization, procurement policy, control of the progress of the project, and coordination and communications between parties. Preparing better storage facilities near the site and avoiding unnecessary material handling are recommended. Employing qualified on-site administrative staff by the contractors to avoid mistakes in quantity surveying and overallowances, ordering mistakes, and poor coordination between warehouse and construction should be done. Employing skilled experienced labor and supervisors and implementing training programs for the jobs should be done. Introduce a good security system including fencing, lighting, and secured storage to avoid theft and vandalism. 15–21% allowance for construction materials wastage in Jordan is recommended.
The author declares that there is no conflict of interests regarding the publication of this paper.