Case study of waste material 2 development projects

. We can interpret the waste material in construction as loss or loss of material resources, time (by looking at labor and equipment), and also capital, this is caused by activities that require costs, either directly or indirectly, but do not add value at all. construction service products. This research compares the material waste that occurs in 2 project case studies, namely the XYZ factory construction project, and the supermarket building project in Jakarta, and compares the causes of material waste in the two projects. The research methodology is by obtaining secondary data from each project and conducting a questionnaire to find out the comparison of the causes of material waste in the two projects. The most waste in the construction of the XYZ factory was: column work at 34%, the second largest was floor slab work at 10% and the third rank was 6% for ground slab main building work while the most supermarket waste building was Steel structure with a percentage of material remaining 14.5765%, concrete Fc 32 F/A with a percentage of remaining material of 11.5912% and iron in diameter 25 with a percentage of remaining material of 9.1921%. The causes of waste in the two projects are different from one another. Even though there are 3 similarities in the causes of waste material.


Introduction
In general, the use of materials will cause a lot of waste material that has been estimated in construction projects [1], meaning that waste material is a very urgent problem in Felixius and Waty's research [2].We can interpret the remaining material in construction as loss or loss of material resources, time (by looking at labor and equipment), and also capital, this is caused by activities that require costs, either directly or indirectly, but do not add value at all. in construction service products [3].Material is one of the important components that have a fairly close influence on the cost of a project, so with the presence of a large enough remaining construction material, it is certain that there will be swelling in the financing sector [4] Material as one of the components that has a contribution of 40 % to 60% of the total project cost [5].In every implementation of a building construction project, the appearance of residual material is unavoidable [6].Waste in construction can be interpreted as a loss or loss of various resources, namely material, time (related to labor and equipment), and capital, which is caused by activities that require costs directly or indirectly but do not add value to the final product for service users [7].Research conducted by Bossink and Brouwers (1996) in the Netherlands focuses on preventing the increase of waste materials in the future.The main goal is to reduce the use of non-renewable materials.Provide encouragement to use renewable materials and secondary resources.Examples of secondary materials are leftover materials from the results of construction *Corresponding author: mega@ft.untar.ac.id and demolition which can be reused as raw materials for production in new construction projects [8].
The research objectives are: 1. Knowing the comparison of waste material calculations for 2 project studies, namely the construction of factories and supermarket buildings.2. Knowing the comparison of the causes of waste material in 2 project studies, namely the construction of factories and supermarket building.
15 jobs with a waste below 1% were obtained.Of the 11 most wastes, the 3 highest waste materials were obtained, namely column work by 34% which was caused by the number of connections when working on the column.Furthermore, for floor slab work it was 10% and the third rank was 6% for ground slab main building work [9].

Case study 2: supermarket building waste material
From the Pareto diagram Fig.Of the 10 largest materials (Table 1), the three largest were taken and the causes were determined as follows [10]: 1.The cause of the remaining material on the steel structure is due to cutting errors.2. The cause of the remaining f'c 32 F/A concrete material is when the concrete reinforcement is carried out beyond a predetermined limit so it must be broken down.3. The cause of the remaining 25-diameter iron material is due to cutting errors.

Case study 1: main causes of overall material leftover XYZ plant
Taking the 3 main causes as a whole aim so that each of us knows the main causes of any remaining materials that affect the project.Questionnaire result data has been analyzed using RII and has been sorted in Table 2.The design source data from RII is sorted, it can be seen that statement 10 is ranked 1st with RII 0.844 and a very high level of importance, which means that statement 10 has a great influence on overall waste.Statement 10 is "Lack of coordination with contractors and lack of knowledge about construction" [9].
Ranking second after the design source data from RII is sorted, it can be seen that statement 6 with RII is 0.811 and the level of importance is very high, which means statement 6 is very influential on the waste as a whole.Statement 6 is "Not paying attention to the size of the product used" [9].
Statement 16 is ranked third and has an RII value of 0.794 and a high level of importance, which means statement 16 is very influential on the overall waste.The content of statement 16 is "Inadvertent handling of material during unloading to be put into the warehouse" [9].From this data, the 10 best RII ratings are listed in Table 3.

Case study 2: causes of material waste overall supermarket building project category
The following is the relative importance index ranking method for the entire category.
From Table 4, the relative importance index values of all categories have been sorted from the largest to the smallest.The first rank is design changes with a relative importance index value of 0.875 and the importance level is very high.The second rank is the amount of material needed is unknown due to imperfect planning with the relative importance index value is 0.869 and the importance level being very high.The third rank is ordering errors, excesses, shortages, etc. with a relative importance index value of 0.866 and a very high level of importance.The ranking results are grouped into the 10 largest ratings as shown in Table 5. Damage due to transportation to and at the project site causes material to be wasted or material sent needs to be recalculated or material is scattered so that an additional volume of material is needed.

Analysis of 10 causes of waste material in supermarket building projects
Analysis of the 10 biggest causes of waste material in Supermarket Building Projects are: 1. Design changes.Design changes are the most common thing that occurs because with an unclear initial design, the consultant completes and improves the design resulting in changes in both details and the entire design, which affects the amount of material needed.2. The amount of material required is unknown due to imperfect planning.The amount of material needed is unknown because imperfect planning causes work changes in the form of changes in detail drawings and changes in other drawings so that the amount of material needed is not known exactly.3. Order errors, excess, shortage, and so on.Ordering errors in the field result in excess material, or also a shortage of material caused because the material ordered is not as expected so that it turns into waste which results in leftover material.4. Inaccurate field measurements resulting in excess volume.Measurements in the field are not accurate resulting in excess volume of material that has been determined.5. Errors when cutting material.Errors when cutting the material result in leftover material that cannot be used anymore, such as in concrete iron which results in steel structure and fc'32 concrete work.6. Purchase of materials that do not comply with specifications.Purchasing materials that are not in accordance with specifications results in the purchase of re-materials resulting in losses in a project.7. Poor material control in the project and management planning for the remaining materials.implementation of work on the project, as well as material management planning for the remaining material on a project that is inappropriate and bad resulting in material waste on the project.8. Measurements in the field are not accurate resulting in excess volume.The lack of incentives also affects employee loyalty, so incentives are really needed that are properly managed so as to increase employee loyalty which can reduce the waste that occurs.9. Error ordering goods, because it does not master the specifications.There was an error in ordering goods because they did not master the specifications which resulted in repeated ordering of goods so that the old goods were not used because the logistics sector did not master the specifications.10.Designers are not familiar with other types of products.Designers do not know other types of products well which results in having to order or buy only known goods because other products may be of the same type but the designer does not know about them resulting in waste because the goods that arrive can be excessive or reduced depending on the existing stock.

Comparison of factory waste material and supermarket buildings are in terms of the most waste material
In the construction of most waste factories column work by 34%.Then on the floor slab work by 10% and the third rank by 6% on the ground slab main building work.The biggest cause of column work waste is the number of connections [9] which can be seen in Table 6.The amount of material required is unknown due to imperfect planning.

2.3
Careless handling of materials during unloading to be put into the warehouse Order errors, excess, shortage and so on In the supermarket building, the most waste is steel structure with a percentage of remaining material of 14.576%, concrete fc 32 F/A with a percentage of remaining material of 11.591%, and diameter reinforcing steel 25 iron with a percentage of remaining material of 9.192% which can be seen in Table 6.
The cause of the most waste in steel structures and iron diameter 25 is material cutting errors and the biggest cause of waste in fc 32 concrete is when concrete reinforcement is carried out beyond a predetermined limit so it must be broken into [10].
The main causes of waste material are factory, construction projects and supermarket building projects.The main cause of the remaining material from the XYZ factory are, which can be seen in Table 6 as follows: 1. Lack of coordination with contractors and lack of knowledge about construction.2. Lack of attention to the size of the product used.3. Careless handling of materials during uploading to be put into the warehouse.
The main causes of material waste in supermarket building projects are, which can be seen in Table 6 as follows: 1. Design changes.2. The amount of material required is unknown due to imperfect planning.3. Order errors, excess, shortage, and so on.
From the results of the discussion above, the comparison of waste material in factory construction projects and supermarket building projects is that there are similarities for the two causes of waste material which are the causes of waste in the two projects, namely:

Comparison of factory waste material and supermarket buildings are: in terms of the most waste material
In the construction of most waste factories column work by 34%.Then on the floor slab work by 10% and the third rank by 6% on the ground slab main building work.The biggest cause of column work waste is the number of connections.
In the supermarket building the most waste is Steel structure with a percentage of remaining material of 14.576%, concrete f'c 32 F/A with a percentage of remaining material of 11.591% and diameter reinforcing steel 25 with a percentage of remaining material of 9.192%.
The cause of the most waste in steel structures and iron diameter 25 is material cutting errors and the biggest cause of waste in f'c 32 concrete is when concrete reinforcement is carried out beyond a predetermined limit so it must be broken.

The main causes of waste material are factory construction projects and supermarket building projects
The main cause of the rest of the factory material are: 1. Lack of coordination with contractors and lack of knowledge about construction.2. Pay less attention to the size of the product 3. Careless handling of materials during unloading to be put into the warehouse.
The main cause of material waste of material waste in supermarket building projects are: 1. Design changes.2. The amount of material required is unknown due to imperfect planning.3. Order errors, excess, shortage, and so on.
There are similarities in the comparison of waste from the 10 biggest causes of waste from each project, namely: 1. Field measurements are inaccurate resulting in excess volume.2. Purchase of materials that do not comply with specifications.3. The amount of material needed is unknown because of imperfect planning.There are differences in the 10 biggest causes of material waste from each project, namely: 1. Lack of coordination with contractors and lack of knowledge about construction, is a rating.2. Less attention to the size of product used.3. Careless handling of materials during uploading to be put into the warehouse.4. Design changes. 5. Order errors, excess, shortage and so on.6. Error when cutting the material.7. Equipment that does not work properly.8. Lack of incentives affecting employee loyalty.9. Errors in ordering goods, because they do not master the specifications.10.Designers are not familiar with other types of products.11.Improper storage causes damage.12. Damage due to transportation to/at the project site.13.Work accident in the field.14.Equipment that does not work properly.

Suggestion
Suggestions from the conclusions above are pay more attention to the 6 main causes of waste material for factory and building projects, namely: 1. Lack of coordination with contractors and lack of knowledge about construction.2. Pay less attention to the size of the product used.3. Damage due to transportation to/at the project site.4. Design changes.
5. The amount of material required is unknown due to imperfect planning.6. Order errors, excess, shortage, and so on.

Fig. 2 .
Fig. 2. Pareto diagram of remaining materials for the construction of a supermarket building.

Table 1 .
The 10 most waste materials for the supermarket building construction project.

Table 2 .
Rating RII causes major waste materials.
Lack of attention to the size of the product used results in an ordering error which results in waste due to inappropriate product sizes such as in ceramic work.3. Careless handling of materials during uploading to be put into the warehouse.When putting goods into the Warehouse, those who are not careful during unloading cause the goods to be damaged or broken, causing reordering which results in waste material on the project.

Table 4 .
[10]ng (RII) for the Overall Supermarket Category[10].Work accidents in the field.Work accidents in the field result in the death of workers or work being hampered because work must be temporarily stopped so that it can cause job changes which can cause waste to occur.6.The amount of material required is not known due to imperfect planning.The amount of material needed is unknown because imperfect planning causes work changes in the form of changes in detail drawings and changes in other drawings so that the amount of material needed is not known exactly.

Table 6 .
Comparison table of 2 project waste material case studies.
1. Field measurements are inaccurate resulting iin excess volume.Measurements in the field are not