* Corresponding author: abduh@si.itb.ac.id
DEVELOPMENT OF ENVIRONMENTAL CRITERIA FOR READY-MIXED CONCRETE IN INDONESIA
Muhamad Abduh1* and Aryo Danurendro2
1Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, Indonesia, abduh@si.itb.ac.id
2Chevron Indonesia, Jl. Asia Afrika No. 8, 12th Floor, Jakarta, Indonesia, danurendro@gmail.com
Abstract
Ready-mixed concrete is increasingly being used in Indonesian construction projects due to its more controllable quality and relatively high productivity. However, the use of ready-mixed concrete has potential of negative impacts to the environment, such as large consumption of energy and natural resources, waste generation, air and water pollution, soil contamination, dust and noise generation. The existing Indonesian National Standard (SNI) that regulates the use of ready-mixed concrete does not include environmental impact consideration yet, while other countries have begun to introduce it to their standards. This paper presents a study to generate recommended environmental criteria for ready-mixed concrete that are suitable to be implemented in Indonesia.
The environmental criteria were adopted from literatures and available standards in the United States and Australia after their compliances to Indonesian construction industry’s practices were assessed in term of their importance and ease of implementation. The assessment of importance and ease of implementation for each criterion is laid out based on by the opinion of respondents, which are 8 ready-mixed concrete suppliers and 11 medium and large-size contractors, using questionnaires and interviews. The environmental criteria then were categorized into three categories: ‘high’, ‘moderate’, ‘low’, and ‘need more research’. The recommended environmental criteria are targeted to the ready-mixed suppliers and the contractors. However, some challenges were identified for the environmental criteria could be effectively implemented and most of the challenges could effectively be solved by the government with the issuance of policy and standards related to the environmental criteria in ready-mixed concrete.
Keywords: environmental criteria, contractor, ready-mixed concrete, supplier, sustainable construction
Introduction
Ready-mixed concrete is increasingly being used for structural components of buildings in Indonesian construction projects. This is mainly due to its more controllable quality and relatively high productivity compared to traditional concrete batching and mixing practices. This becomes a normal requirement for construction project to use ready-mixed concrete nowadays. Despite of its advantages, the use of ready-mixed concrete still has potential of negative impacts to the environment, such as large consumption of energy and natural resources, waste generation, air and water pollution, soil contamination, dust and noise generation, CO2 and NOx emission [1]. Considering the use of ready-mixed will ever be growing, efforts to reduce its negative impacts to environment are necessary to be established as part of concreting standards.
Indonesia has series of national standards (SNI) related to concreting works since 1955. The standard related to ready-mixed concrete was established in 2016, named as SNI 4433-2016, which was adopted from ASTM C94/C94M-14. However, this national standard, related to ready-mixed concrete, as well as other standards related to general
concreting are not yet considering explicitly requirements to prevent negative impacts of concreting to the environment.
Negative Impacts of Ready-mixed Concrete
Ready-mixed concreting process, like concreting process in general, consists of batching, mixing, transporting/delivery, pouring, compacting, finishing, and curing [2]. The main environmental issues related to those concreting processes are high energy/fuel consumption and its generated gas emission. However, in ready-mixed concreting, the issues generated from batching plant’s operation are relatively low compared to the same issues generated from the cement production [3][4][5] as depicted in Table 1.
Table 1. Emission Factor of Concrete Production (adopted from [5])
Activity Emission Factor Unit
Coarse aggregate – Granite 0.0459 t CO2-e/ton
Coarse aggregate – Basalt 0.0357 t CO2-e/ton
Fine aggregate 0.0139 t CO2-e/ton
Cement 0.8200 t CO2-e/ton
Fly-ash (F-type) 0.0270 t CO2-e/ton
GGBFS 0.1430 t CO2-e/ton
Concrete batching 0.0033 t CO2-e/m3
Concrete transport 0.0094 t CO2-e/m3
On site placement activities 0.0090 t CO2-e/m3
Regarding concrete waste generated from batching plant, it was estimated about 20-80 tons per month in UK [6]. The main sources of waste are coming from the cleaning process of batching plant and truck mixers, and from the rejected fresh concrete due to intolerable quality when arrived in the project sites. The rejected fresh concrete could become solid waste that will potentially pollute soil and water [7]. The pH of polluted water could reach 11.5 (acid) that could damage further the ecosystem. On the other side, the alkali contained in concrete waste could also be harmful for human skin [6].
Other side product of ready-mixed batching plant that will affect the environment badly is dust. The dust could mainly be generated from activities such as aggregate storage in open space, imperfect cement pouring to the truck mixer in dray batch process, and transportation of truck mixer to the project site. The dust could cause visual pollution and be harmful for human health such as eyes irritation, nose and throat irritation, and even chronic lung disease. The noise could also be considered as one negative impact of ready- mixed concreting [8].
The noises could be generated from aggregate mixing, transportation, pumping, and competing by vibrator. Long-term exposure to the noise could be harmful for human’s ear temporarily or permanently [8]. Moreover, ISO has identified negative impacts to the environment for each step of ready-mixed concreting process (Table 2) [9].
There are some literatures based on research that proposed recommendation to reduce such negative impacts to the environment that could be implement to the ready-mixed concreting processes. Some recommendations are related closely to the efforts that the contractors (C) as well as the suppliers (RMCS) could be implement, while other recommendations are related to more wide industry and policy level of efforts that government (G) or owners (O) should take part. The following Table 3 shows the recommendations from those literatures.
Table 2. Environmental Impacts of Ready-mixed Concreting (adopted from [9])
Sub-Phase Global
Climate Change
Natural Resource
Use
Eutrophication, Acidification, Air Pollution
Water Pollution
Soil Contamination
Waste Noise/
Vibration Material
supply
Cement CO2 Fossil
fuel, Non- Metallic mineral- limestone
NOx, Sox, PM* NOx Sox Heavy
metal
Heavy metal
Mixing Water CO2 Water NOx, Sox, PM
Aggregate CO2 Non-
Metallic mineral,
air
NOx, Sox, PM NOx Sox Heavy
metal
Heavy metal Powder Sludge
Supplementary cementitious
material
CO2 NOx, Sox, PM NOx Sox
Heavy metal
Heavy metal
Chemical Admixture
CO2 NOx, Sox, PM Nonylphe
nol derivative
Nonylphenol derivative
Concrete Production CO2 Fossil fuel NOx, SOx, PM NOx SOx Sludge Noise/
Vibration Transpor
tation/de livery
Truck CO2 Fossil fuel NOx, SOx, PM Noise/
Vibration Execute Pouring CO2 Fossil fuel NOx, SOx, PM NOx SOx
Heavy metal
Noise/
Vibration
Compaction CO2 Fossil fuel NOx, SOx, PM NOx SOx Noise/
Vibration Curing CO2 Fossil fuel NOx, SOx, PM NOx SOx
Heavy metal
Waste
* PM = Particulate Matter
Table 3. Recommendation from Literatures
References Recommendation Followed up by
Uchikawa (2000) [10]
1. Use recycled material from other industries for cement production 2. Develop environmental friendly concrete technology
3. Develop concrete ingredients, casting method, and curing method 4. Recycle concrete waste
G G, RMCS G, C, RMCS G, C, RMCS Metha (2001)
[11]
1. Cement conservation 2. Aggregate conservation 3. Water conservation 4. Increase concrete durability
G, C, RMCS G, C, RMCS G, C, RMCS G, O, C, RMCS Cosgun & Esin
(2005) [7]
1. Dust control 2. Water management 3. Waste management 4. Noise control
5. Fuel, lubricant, and other chemical material control 6. Education
7. Optimal natural resources usage
G, RMCS G, C, RMCS G, C, RMCS G, RMCS G, RMCS G
G, O, C, RMCS Meyer (2009)
[12]
1. Use cementious material other than Portland cement 2. Use of recycled materials
3. Increase durability and life service of building
4. Improve mechanical other technical properties of concrete 5. Reuse of wash water
G, RMCS G, RMCS G, O, C G, O, C, RMCS G, C, RMCS
Methodology
This study had objective to generate recommended environmental criteria for ready-mixed concrete that are suitable to be implemented in Indonesia. The coverage of the study was based on the ready-mixed concreting aspects and processes performed by contractor, ready-mixed concrete supplier and raw material suppliers. In Figure 1, the coverage of the study is depicted by dashed line. Therefore, there are two partied would be studied in this study: contractor (C) and ready-mixed concrete supplier (RMCS).
Raw Materials Specification
Batching &
Mixing Testing &
Storage Delivery
Selection
Concreting Concrete
Specification
Cleaning and Waste Treatment Selection
Cleaning and Waste Treatment
Cement Production &
Delivery
Aggregate Production &
Delivery
Admixture Production &
Delivery Operation & Maintenance Selection
Specification OWNER
CONTRACTOR
READY-MIXED CONCRETE
SUPPLIER
RAW MATERIALS SUPPLIER
Setting Up Curing
Figure 1. Ready-mixed Concrete Processes, Aspects, and Study’s Coverage
In order to achieve the objective of the study, the two following steps are important:
1) Defining the environmental criteria for ready-mixed concrete. The environmental criteria for this study was developed based on several literatures as depicted in Table 3 and also based on available standards from USA and Australia that have implemented sustainable construction; the USA standards are the Storm Water Best Management Practice Handbook by CASQA [13], and the Sustainable Concrete Plant Guidelines by NRMCA [14]; while the Australian standards are the Environmental Guidelines for Major Construction Sites by EPA [15], the Environmental Guidelines for Concrete Batching Industry by EPA [16], and the Environmental Best Management Practice Guide Line for Concreting Contractors by DEC [17]. Based on this step, there are 39 criteria for RMCS’s side, and 23 criteria for contractor’s side.
2) Assessing the importance and easiness for implementation of the environmental criteria. The assessment was made by asking the level of importance and level of easiness for implementation of each environmental criteria to the contractors and ready-mixed suppliers. The assessment utilized a questionnaire and a follow-up interview method. The questionnaire was used to gain the respondents’ opinion towards their agreements on statements of the importance and the easiness for implementation of each environmental criteria; five scales of answer: “Strongly Agree” (SA), “Agree” (A), “Neutral” (N), “Not Agree” (NA), “Strongly Not Agree” (SNA). Whilst the follow-up interview was used to gain further arguments on the respondents’ answers and other input for the environmental criteria.
The collected data were then analyzed using their frequencies of answers and categorized into “High”, “Moderate”, “Low”, and “Need More Research” (NMR). The algorithm for categorization is depicted in Figure 2 for both level of importance as well as the level of easiness for implementation. The combination of two level of observations can then be decided as depicted in Table 4 that concludes the agreement of respondents towards the environmental criteria.
Frequency (%) of each Question
SA+A > 50%
?
SA A
? High
SA+A >
SNA+NA
?
Moderate
Cross Check with Interview
Any supporting argument?
Needed More Research Can be decided?
Is the argument supportive?
Yes Yes
No
Yes Yes
Yes
No No No
N > 50%
SA+A = SNA+NA
?
Low Yes
No No
Yes Yes
No
No
Legend:
SA = Strongly Agree
A = Agree
N = Neutral
NA = Not Agree
SNA = Strongly Not Agree
Figure 2. Decision Making Process for Criteria Categorization Table 4. Decision of Respondents’ Agreement on the Criteria
Decision Meaning
Importance Implementation
High High Respondents tend to agree with the criteria
Moderate Moderate Respondents tend to agree with the criteria with notes Low Low Respondents tend to not agree with the criteria NMR NMR Respondents might not be familiar with the criteria
Data Collection
Coverage geographical area of the study is city of Bandung, located in the middle of West Java Province and its capital city. With population approaching 2.5 million, this city is considered as one of the big and ever growing cities in Indonesia since its popularity for its tourism, and therefore construction projects are common sighting surrounding the city. The ready-mixed concrete industry has been growing as well in Bandung vicinity area; at the time the study was conducted, there are 8 ready-mixed concrete suppliers and all of them were respondents for this study. Furthermore, for contractor’s respondents, the study managed to have 11 respondents of medium and big contractors to participate.
Based on decision making algorithm in Figure 2 and Table 4, all 39 criteria for RMCS’s side and all 23 criteria for contractor’s side were analyzed. An example of analysis spreadsheet is shown in Table 5; only small part of a big table is provided in this paper (more information on this table will provided by request to the corresponding author).
A recap of analysis results is depicted in Table 6. It can be said that almost all criteria are considered as important and could be moderately easy to be implemented by the RMCS (79.5%) and contractors (100%). However, there are some criteria were required more research and clarification from the respondent, especially from the RMCS.
Table 5. Example of Spreadsheet for Analysis
Aspect Environmental Criteria Objective
Respondents’ Answers
Importance Implementation
%
Decision
%
Decision S
N A
N
A N A S A
S N A
N
A N A SA RMCS-Side
General 1 Batching plant location (distance to the community)
Reducing noise, dust, water and
soil pollution 0 0 0 50 50 H 0 13 0 63 25 M 2 Environmental
assessment document
Planning for reducing noise, dust, water and soil pollution
0 0 0 50 50 H 0 13 13 63 13 M 3 Environmental
management plan
Energy and natural resources efficiency
Waste reduction
Dust, noise, water pollution controls
0 0 25 63 13 M 0 13 25 63 0 M
4 Use of renewable energy Energy
efficiency 0 50 0 38 13 NMR 0 75 13 13 0 L 5 Noise damper Reducing noise 0 50 0 25 25 NMR 0 25 38 25 13 M
Table 6. Number of Criteria Categorized into Level of Importance and Implementation
Category Supplier Contractor
Importance Implementation Importance Implementation
High (H) 19 4 7 0
Moderate (M) 15 27 16 23
Low (L) 1 5 0 0
NMR 4 3 0 0
Total 39 39 23 23
Based on the findings of the study, the lists of recommended environmental criteria for ready-mixed concrete are provided in the Appendices: Appendix A for the ready-mixed concrete supplier (RMCS) and Appendix B for contractor (C). However, there are 33 criteria for the RMCS’s side and 16 criteria for the contractor’s side; about 6-7 criteria were deleted from the recommendation.
Discussion on the Recommended Environmental Criteria
Ready-mixed Concrete Supplier’s Side
In general, the recommended environmental criteria for ready-mixed concrete from the supplier’s side are as follow:
1) In selection process of raw material suppliers, priority should be put on the cement supplier that has environmental management system established and on the aggregate supplier that is the nearest from the batching plant.
2) Reducing the use of clicker for concrete mix by the utilization of SCM and its quality control improvement.
3) Reducing the use of new aggregate materials for concrete mix by the utilization of recycled aggregate from concrete waste.
4) Reducing the use of clean water for concrete mix or for cleaning process by the utilization of recycled wash water.
5) Reducing dust spreading by selecting appropriate batching plant location, planting vegetation, spraying water, and using dust protection.
6) Improve efficiency of energy usage by the utilization of low fuel consumption equipment and vehicles, routine maintenance of equipment, optimal route selection, and effective driving practices and skill of the drivers.
7) Reducing noise by the utilization of selecting appropriate location for batching plant and noise protection/barrier.
8) Protection against water and soil contamination by the utilization of special area for cleaning truck mixer, the use of washing bay, waste water treatment, and reusing concrete waste for batching plant infrastructure.
There are some environmental criteria that were considered to have high level of importance but low level of implementation in RMCS’s perspective, they are:
Considering commitment and performance of environmental management for selecting raw material suppliers. For aggregate supplier, mining permit and business permit are essential to be used as pre-requisite in selection process.
Selecting the cement supplier based on the nearest location to the batching plant, the lowest price, and capacity. This will reduce emission generated from transportation of cement from supplier to the batching plant.
The use of renewable energy for concrete production. This is still a challenge in Indonesia, since renewable energy is still rarely available for industry purposes.
Reducing disturbance to the community surrounding the batching plant by only producing concrete during the day shift. However, most of construction projects restrict concrete delivery during the day shift and suggest night shift delivery. This is only important for batching plant that is located near a dense community area.
On the other hand, there are two environmental criteria that are considered unfamiliar to the RMCS, and therefore needing more research on those criteria. They are:
Regulation on aggregate loading rate from dump truck to aggregate stock pile.
This issue is related to generation of dust from loading operation. There is no data on the rate of loading that will not produce much dust to be considered as negative impact to the environment.
Cleaning procedure of drum mixer cleaning using rock/stone out method. There is no information on the method’s details, limitation, and how could this procedure could reduce the use of aggregate and water.
Contractor’s Side
In general, the recommended environmental criteria for ready-mixed concrete from the contractor’s side are as follow:
1) In selection process of RMCS, priority should be on the commitment and performance of RMCS to the environment, and its eagerness to make long-term collaboration.
2) Reducing the use of clinker for concrete mix by the ordering the use of SCM.
3) Reducing dust spreading in construction site by providing paved access to the site and cleaning bay for concrete truck mixer and pump truck.
4) Reducing water pollution by protecting public drainage and providing special location for cleaning and concrete waste disposal.
5) Reducing soil contamination by providing special location for cleaning and concrete waste disposal, and also by cleaning the spilled concrete waste.
6) Reducing concrete waste by reusing it for non-structural application in construction project site.
7) Reducing air pollution and noise by evaluating the condition of concrete equipment used in the construction site.
Challenges to Meet the Recommended Criteria
Based on the follow up interviews made in this study to the respondents there are some challenges identified to achieve the recommended environmental criteria for ready mixed concreting process, they are:
Increasing Competition of RMCS Business. Even though the growth of construction is constantly increasing, as demand for RMCS business, the number of supplier in an area is considered too many for supporting the demand. This makes RMCS business becomes more competitive and pushes the suppliers to reduce their cost of production. In this situation, suppliers are not willing to add more cost of production to comply with the environmental criteria yet.
Limited Availability of Recycled Aggregate. Recycled aggregates made from waste hardened concrete is hard to find in Indonesia; more of concrete waste available are in the form of fresh concrete, yet the quantity is still not much to be used for recycled aggregate. Moreover, there is no technical standard related to the use of recycled aggregate for concrete in Indonesia yet.
Limited Availability of SCM Sources. It is still considered rare that SCM is used in Indonesia. Only fly ash that is considered as the most used SCM nowadays.
Other SCM types such as slag and silica fumes are still not popular to be used. The real problem would be the constant supply quantity and sources of SCM are not managed well. This is due to inappropriate categorization SCM as hazardous waste (B3).
Limited Number of Green Projects. Green projects are believed to be motivation for the implementation of environmental criteria in construction, including for ready-mixed concrete. However, the growth is not as expected. Demand from the owner with green project initiative could help contractor to innovate their activities in construction to be more environmental friendly and backed up by the cost supported by the owner.
Lack of Compliance and Law Enforcement in Environmental Aspect. Even though general regulation on environmental management for construction project has been enacted, yet the implementation and enforcement are far from adequate in Indonesia. Regulations related to environmental management are not effective and would end up with fulfilling merely administration process and paper works. This situation would demotivate the organization that commit supporting environmental campaign.
Lack of Supporting Institutions. There is lack of appropriate and capable institutions that could support continuously the development of the technical aspects related to environmental management in Indonesia. The standardization effort in Indonesia is still considered as a project and without support from robust
research. Examples from USA (ACI or American Concrete Institute, and NRMCA or National Ready-Mixed Concrete Association) and Australia (CCAA or Cement Concrete Aggregates Australia) should be enough to illustrate the needed institutions in Indonesia.
Low Self-awareness. One of the most important challenges is lack of self- awareness of individual to protect the environment, including the persons working in contractor and RMCS. Education and incentives from government related to environmental awareness is necessary in this case.
Conclusion
This paper presents a study to recommend environmental criteria for ready-mixed concrete in Indonesia from perspective of the contractors as well as from the suppliers. There are 33 environmental criteria that should be addressed by the suppliers, while there are 16 environmental criteria that should be addressed by the contractors.
However, some challenges were identified for the environmental criteria could be effectively implemented. The challenges are competition, availability of recycled aggregate, availability of SCM and its sources, green project motivation, law enforcement, supporting institutions, and self-awareness. Most of the challenges could effectively be solved by the government with the issuance of policy and standards related to the environmental criteria in ready-mixed concrete.
References
1. T. Bremner, “Environmental Aspects of Concrete: Problems and Solutions”, the 1st All-Russian Conference on Concrete and Reinforced Concrete, http://www.unb.ca/civil/materials/materialsgrp/eac.pdf, accessed on June 3, 2018.
2. R. Peurifoy, C. Schexnayder, and A. Shapira, Construction Planning, Equipment, and Methods, 7th edition, McGraw-Hill, New York, 2007.
3. M. Marceau, A. Nisbet, A, and M. VanGeem, Life Cycle Inventory of Portland Cement Concrete, Portland Cement Association, Illinois, 2007.
4. R. Pulselli et. al., “Specific energy of cement and concrete: An energy-based appraisal of building materials and their transport”, Ecological Indicators, Vol. 8, page 647-656, 2007.
5. J. Flower, and J. Sanjayan, “Greenhouse gas emissions due to concrete manufacture”, The International Journal of Life Cycle Assessment, Vol. 12, page 282-288, 2007.
6. B. Sealey, G. Hill, and P. Phillips, “Review of Strategy for Recycling and Reuse of Waste Materials”, International Symposium, Dundee University, Thomas Telford, 19- 20 March, page 325-335, 2011.
7. N. Cosgun, and T. Esin, “A study regarding the environmental management system of ready mixed concrete production in Turkey”, Building and Environment, Vol. 41, page 1099-1105, Elsevier, 2006.
8. P. Hughes, and E. Ferret, Introduction to Health and Safety in Construction, Elsevier, Oxford, page 315-375, 2008.
9. ISO, ISO 13315-1: Environmental management for concrete and concrete structures, 2012.
10. H. Uchikawa, “Approaches to Ecological Benign System in Cement and Concrete Industry”, Journal of Materials in Civil Engineering, ASCE, November 2000, page 320-329.
11. P. Metha, “Reducing Environmental Impact of Concrete,” Concrete International, October 2011.
12. C. Meyer, “The Greening of Concrete Industry’, Cement & Concreter Composites, Vol. 31, page 601-605, Elsevier, 2009.
13. CASQA, Storm Water Best Management Practice Handbook, CASQA, California, 2003.
14. NRMCA, Sustainable Concrete Plant Guidelines Version 1.1, NRMCA, Silver Spring, 2011.
15. EPA, Environmental Guidelines for Major Construction Sites, EPA, Victoria, 1996.
16. EPA, Environmental Guidelines for the Concrete Batching Industry, EPA, Victoria, 1998.
17. DEC, Environmental Best Management Practice Guide Line for Concreting Contractors, DEC, Sydney, 2004.
Appendices
A. Supplier-Side’s Recommended Environmental Criteria for Ready-Mixed Concrete
No Criteria Requirement
General
1 Batching plant location
Comply with urban planning regulation
Minimal distance from the nearest human settlements 2 Environmental
assessment regulation
Environmental assessment document should be available and comply with local regulation
3 Environmental management plan
Environmental management plan should be set up and well documented 4 Noise damper Noise damper should be installed for noisy equipment
5 Vegetation Providing vegetation in batching plant area
Soil for vegetation should be protected against cement contamination 6 Impermeable
pavement
Impermeable pavement to drain rain water and waste water to the water treatment
7 Labor awareness Policy and training program for labor environmental awareness Raw Material Supplier Selection
8 EMS of cement supplier
Cement supplier should have certified EMS 9 Nearest aggregate
supplier
Aggregate supplier’s location is the nearest to the batching plant Raw Material Specification
10 Blended cement Use of cement type that has less clinker than Ordinary Portland Cement (OPC) 11 Supplementary
cementious material
Use of the supplementary cementious material such as fly ash, slag or silica 12 Recycled aggregate Use of recycled aggregate extracted from waste of the previous production 13 Recycled water Use of recycled water claimed from the mixer cleaning process
Storage
14 Water spraying Effective water spraying to the stock pile to prevent dust spreading with minimum use of clean water.
15 Dust protection Use of dust collector, baghouse or filter for cement silo and fly ash 16 Silo’s volume
indicator
Availability of indicator of silo’s volume to prevent overfilled cement in silo 17 Admixture storage Admixture storage that has secondary containment
Batching and Mixing
18 Job mix Reduced cement content of the job mix based on test records 19 Water Reducing
Admixture
Optimum use of water reducing admixture
20 Production Equipment Low energy consumption of production equipment
21 Loading Rate Material Regulation on aggregate and cement loading rate and to the bin, hopper, and/or mixer
22 Dust protection Use of dust collector/baghouse/filter for bin or hopper 23 Conveyor Belt
Cleaner & Spillage Control
Use of belt cleaner and spillage control on conveyor
Delivery
24 Concrete volume delivered
Accurate volume of concrete delivered as ordered 25 Route Effective transportation route selection
26 Fleet specification Use of fuel-efficient truck mixer 27 Truck Mixer
Maintenance
Periodic maintenance and emission test for truck mixer Cleaning and Waste Treatment
28 Cleaning intensity Limited time for cleaning time of equipment
No Criteria Requirement 29 Reuse of water Use the reused water for cleaning process 30 High pressure low
volume hose
Use of high pressure low volume for cleaning 31 Reused concrete Use of reused concrete for batching plant facilities
32 Concrete reclaimer Use of concrete separator for reclaiming aggregate to be reused 33 Waste water treatment Availability of waste water treatment
B. Contractor-Side’s Recommended Environmental Criteria for Ready-Mixed Concrete
No Criteria Requirement
General
1 Environmental management plan
Provide document of environmental management plan including environmental impacts identification and control
2 Labor awareness Policy and training program for labor environmental awareness Concrete Ready-Mixed Supplier Selection
3 Supplier’s commitment and performance on environmental issues
Considering supplier’s commitment and performance on environmental issues besides quality, price, and distance in selection process
Evaluating the commitment and performance by site visit to the batching plant
4 Long term collaboration
Long-term collaboration with concrete ready-mixed suppliers in accommodating environmental aspect to the concrete works Concrete Specification
5 Supplementary cementious material
Support the use of the supplementary cementious material such as fly ash, slag or silica
Setting up and Concreting 6 Project access
pavement
Provide paved access to the concrete works location on the project site
The access is water spayed regularly to prevent dust 7 Protection to public
drainage
Reroute public drainage to avoid concrete contamination
Provide temporary closure to the public drainage 8 Evaluation of
concreting equipment from supplier
Make sure concrete pump is well maintained functioning
Make sure concrete pump truck is well maintained and emission controlled 9 Location of concrete
pump
Far from the public drainage to prevent possible concrete contamination 10 Inspection on spilled
concrete
Inspection of spilled concrete and its cleaning Cleaning and Waste Treatment
11 Cleaning location of equipment
Specific location used for cleaning the concreting equipment: chutes, pipes, pump, crane bucket) to prevent public drainage contamination
12 Residual concrete sedimentation
Flushing residual concrete from truck mixer and providing a bay for sedimentation
13 Collection of spilled concrete
Collection of spilled concrete should be done thoroughly before the concrete hardening
14 Tire cleaning Tire cleaning procedure before the truck mixer leaving the project site 15 Reuse of residual
fresh concrete
Reuse of residual fresh concrete for non-structural components, such as:
working area, car stopper, cansteen, pavement 16 Recycle of residual
hardened concrete
Residual hardened concrete should be clean from the site and recycle as much as possible, such as for: fill, foundation filler, transferred to outside by other party
