Demolished concrete is found a lot.In developed countries, there is a clever method to dispose such demolished concrete by recycling to get a near quality as natural aggregate in order to reduce natural resources and help concrete waste disposal which is called recycled concrete aggregate (RCA). However, in Bangkok, it is now no strict regulation to dispose demolished concrete. This research studied a feasibility of RCA in Bangkok by simulation which many criteria in the model were assumed to be random parameters; therefore, this research created a model by Monte Carlo Simulation which is differed from other RCA business model simulations that normally use constant parameters. In additions, four conditions were set, first: 100-ton-per-hour constant supplied plant, second: 50-ton-per-hour constant supplied plant, third: 100-ton-per-hour uncertain supplied plant, and fourth: 50-ton-per-hour uncertain supplied plant. The result showed the trend of output rather than 1 simple output thanks to the random inputs. In details, the both constant supplied plant can make a profit, additionally; 100-ton-per-hour plant was more worthwhile than 50-ton-per-hour plant thanks to the economics of scale. On the other hand, for the uncertain supply, 100-ton-per-hour plant was loss, but 50-ton-per-hour plant still made a profit.
In general of construction life cycle, constructions are built, demolished and revamp or rebuilt again and again in order to respond human’s needs. A lot of materials are used for civilization. On the other hand, myriad natural resources especially natural aggregate are depleted by human hand.
The more construction, the more natural aggregate is consumed. Likewise, when demolition is coming, demolished concrete is found a lot.Many countries utilize demolished concrete in many ways depending on a government policy. Normally, the steel is removed for reused, other stone with attaching mortar is used for landfill or turn it into recycled concrete aggregate (RCA). For example, in London Olympic 20 12, new buildings or roads are constructed from RCA [ 1 ]. In china, Zhengzhou Yifan Machinery Co., Ltd, who supplies Crushing and Screening Equipment, informed that after they turn demolished concrete into RCA, they brought RCA to produce many constructing things. Generally acceptable, using RCA directly helps use less natural resources.
Fig. 1 Normal practice of RCA in China [ 2 ]
In Thailand, it is no strict regulation. After steel is removed, big demolished concrete is often put into landfills, a deep soil/sand mines and the worst in the public areas. In the long term, it will destroy natural atmosphere.The demolished concrete was thrown in public area as shown in Fig. 2.
Fig. 2 Demolished concrete in public area of Bangkok [ 3 ].
Moreover, there is a business that provides free area for a person who wants to throw away demolished concrete and then, selling as it is in low price than natural resources to a person who wants to do landfill.This is also an effortless model, and still causes such environmental problem.To solve this problem, applying RCA technology will help not only environmental problem but also financial benefit to stakeholders.
Nowadays, RCA is studied in 2 ways: First, technical term—How it can be applied in construction as much as possible thanks to the fact that the more recycled, the less consumption of natural aggregate (NA). Many experiments have been tested (gradual mix or add some additives) for the better property and set the standard [ 4 , 5 , 6 , 7 ]. There are many technologies of concrete recycling processes focusing on RCA’s quality. However, the RCA’s quality is just one part of concrete’ quality. The RCA’s proportion mixed in concrete is the other one influence on concrete’s quality as well.
The other way, commercial term—How it can be set as a business model to create profit. What are the limitations? In conclusion, almost all models were successful in simulation model, and the bigger plant will generate more profits thanks to the economics of scale [ 8 , 9 , 10 , 11 ].
However, all models were still not considered about uncertain supply (normally, fix numbers were used for supply equally to machine’s capacity.) This research tries to create the model that applies uncertain supplied conditions in order to get much more realistic answers with a probability of the output that can be happened. Therefore, Monte Carlo Simulation which is appropriate for uncertain parameters is applied in this research through Excel which is a famous general program. Besides, after obtaining financial ratio output, the results will be shown, first, a comparison of advantages and disadvantages between a big and a small RCA plants under the constant supply and uncertain supply, second, recommend a proper plant size and third, find out the acceptable buying price.
2. Materials and Methods
Before creating each assumption, life cycle assessment of RCA was set in order to see overall background and set the limit of study and was shown in Fig. 4. In details, demolished concrete was assume to be purchased from owner of demolition sites and construction sites or there may be have new job which is collector who collect demolished concrete from each site to sell to RCA plant. After they bring demolished concrete to the plant, RCA was produced, then RCA will be sold to construction material retailers or directly to construction site and some factories which produce product from concreted such as Brick factory. Additionally, the internal process of RCA plant was described in topic 2.1.6 Machine, Capital Cost and maintenance cost.
Fig. 4. Life cycle assessment of RCA
2.1.1 Simulation period
The model was run for 10 years, because it was a huge investment and can surely see the payback period.
36 million tons of cement was consumed in Thailand in 2009 [ 3 ]. There is a lot of demand of coarse RCA even plant 1,000 ton/day still can supply. However, dust (or equivalent to Fine RCA) from the process still does not have research-support that it can be substituted in natural aggregate. Besides, dust is used for land fill and making brick and does not have high consumption. The Coarse RCA was calculated based on substitute natural aggregate about 20 % (This will affect quality less and still can use wildly [ 5 ]), besides, it can be sold all how much a RCA plant can produce. Fine RCA demand was assume to be about half of natural dust demand [ 12 ].
2.1.3 Selling price
Current coarse natural aggregate price was shown in Fig. 5.
Fig 5 5-year trend showed natural aggregate price have increased about 2% per year [ 13 ].
The average RCA selling price in model will be adjusted lower than the natural aggregate price in order to attract in a construction market. The average RCA Selling price was assumed to be constant (to make the model pessimistic). The average scrap steel Selling price was assumed to 5000 Baht per ton.
Bangkok is likely to have enough supply for run the business; however, the problem is that demolished concrete is dispersed and randomly happen ( Nevertheless, in the city has a higher chance to happen). A huge transportation cost will be occurred, if we want to collect to meet demand.
In details, The RCA plant can collect demolished concrete basically from 2 sources: Waste in New Construction site and Demolition site. Each had its own character as Table 1 .
Table 1 Characteristic of demolishedconcrete between new construction and demolition.
Estimated volume of demolished concrete from new construction
From survey to 11 constructors, it was assumed that from concrete consumption about 613.36 cubic meters per month will create demolished concrete about 6.17 ton/month.
There is concrete consumption in Bangkok zone about 7,020,000 cubic meters per year [ 14 ]. And it was assumed that area that the RCA plant support was about 30 percent of Bangkok area.
From all assumptions, using probability to simulate demolished concrete from new construction, it was about 1,059.67 ton per month or 5.09 ton per hour for 30 percent area of Bangkok zone.
Estimated volume of demolished concrete from demolition
From survey, no any demolisher can estimate generating of demolished concrete. One large demolisher tries to make its company to survive by finding continuously demolition job and this can generate demolished concrete about 20.83 ton per hour.
From Department of business development, there were 17 demolishers registering in Bangkok which shows work capital and revenue. However, from yellow pages website, there were 46 demolishers showing up [ 15 , 16 ].
It was assumed that area that the RCA plant support was about 30 percent of Bangkok area. From all information, it was assumed that all demolishers will generate demolished concrete as well, and the amount of demolished concrete was calculated from Interpolation. Finally, average demolished concrete from demolition was about 48.08 ton per hour.
Nevertheless, there was the other research about methods of concrete waste disposal from Pollution Control Department of Ministry of Natural Resources and Environment informing that in year 2005, demolished concrete from construction was about 11.10 ton per hour and from demolition was about 36.28 ton per hour [ 3 ]. Then made an approximately update to the value by Growth rate of Domestic Production of construction from Bank of Thailand provided [ 17 ]. Therefore, it was assumed that currently, demolished concrete from construction was about 12.37 ton per hour and from demolition was about 40.42 ton per hour.
In conclusion, from both assumptions, there were unequal values. Therefore, it was assumed to set those numbers as min and max values; plus losing opportunity of collection about 20 percent. Besides, from the Growth rate of Domestic Production of construction [ 18 ], growth rate will be randomly generated at 1.32 percent with standard deviation 5 percent
2.1.5 buying price
There was no data support, what the exact price of demolished concrete was. From the surveys, sometimes, it is free. Sometimes, it has a high value 150 to 200 baht/Ton (plus transportation cost). And sometimes, we earn money from collecting it. However, from holistic view, in the city (inner area), it is likely to be high value. On the other hand, in the suburb (outer area) it is likely to be less value.
Fig. 6. Value of demolished concrete in Bangkok between inner zone and outer zone.
Therefore, the average buying price will be set as various values starting from 0 baht per ton until it shows unprofitable. (10 baht step-up). (In term of commercial, buying price 0 baht per ton means that RCA plant dispose waste for free. On the other hands, if buying price is higher than 0 baht per ton, RCA plant is paying for dispose waste which is not normal. In fact, customer should pay for the service like other businesses such as car washing. However, in this case, the buying price which was higher than 0 baht per ton was for motivation to collect demolished concrete easier.)
2.1.6 Machine, capital cost and maintenance cost [2, 19, 20]
They were used from data collecting. The testing plant’ sizes were 50 ton per hour and 100 ton per hour in order to see the different between small and big volumes. The operating time was 8 hour per day and 26 day per months which was a standard practice for running factory.
RCA output sizes were randomly depended on suppliers’ information which coarse RCA was about 67% to 85%. Moreover, there was scrap steel waste which also can be saleable. And it was assumed to be about 0.1% to 0.2%, because it was normally removed from demolisher.
The basic machines for the plant and the layout of producing RCA were assumed as in Fig. 6 which is standard model. And the processes are as follows:
The major foreign material such as plastic or other wastes that comes with demolished concrete was assumed to be disposed before putting in the demolished Stock by sellers who sell demolished concrete. (In this state to demolished stock yard was equal 100% input)
Pay loader: transport the demolished concrete from demolished stock to Scrap yard, put into feeder and transport the RCA to buyer’s truck. (No any loss in this state, still 100% input)
Excavator: miniaturize the demolished concrete and remove seeable steel. (The miner foreign material will be disposed again in Scrap yard by labor in RCA plant; therefore, some of input was turn into output as scrap steel).
Feeder: receive demolished concrete to Jaw crusher (No any lose during this state)
Jaw crusher: the first crushing step (No any loss during this state)
Magnetic separator: remove steel from the process. Therefore, some of input was turn into output as scrap steel including state 3 (about 0.1% to 0.2%) which was fed to scrap steel yard.
Vibrating screen: receive RCA from Jaw crusher and Impact Crusher to screen RCA’ size. (No any loss during this state)
Impact Crusher: receive the over size of RCA from Vibrating screen to the second crushing step. (No any loss during this state)
RCA yard: receive RCA from Vibrating screen and there are four piles of RCA depending on size.
In this State, the output of RCA size 4 millimeter to 3/4 inch (Coarse RCA) was assumed to be random from 67.0% to 85.0%, size lower than 4 millimeter (Fine RCA) was assumed to be random from 14.8% to 32.9% and the scrap steel from state 3 and 6 was assumed to be random from 0.1% to 0.2%.
In total, the summation of outputs of Coarse RCA, Fine RCA and scrap steel was equal input of demolished concrete. No any loss of input in the process thanks to the assumption that demolished concrete was assumed to be disposed before putting in the demolished Stock by sellers. However, the randomness still occurred among those outputs
Fig 7 Machines and processes for the RCA plant
2.1.7 Employment generated
All of basic positions had Pay loader driver, Excavator driver, Operating plant labor, Removal foreign material, Officer, Manager, Sales and marketing, Security guard, housemate and Accountant. The number of employees for each position was depended on the plant’s size. Labor Cost will increase about 4% to 6% per year with Bonus about 10% of EBIT.
It was assumed to be first in first out method. Besides, if volume of the inventory was five times of current demand, it is assumed that inventory will be sold out at half of selling price.
Location will be stay in the area the far away from natural aggregate crushing plant [ 21 ] in order to have a low competitive. However, the other factor was the land price; the RCA plant should be located in the proper area and not lead to high investment. The area of the RCA plant was about 1,000 to 2,000 Square meters depending on the plant’s size in order to support the inventory and goods about 30 days. We assume the plant was found in the middle zone of Bangkok which can have a higher chance to collect demolished concrete and the cost of investment was not too high [ 22 ].
Demolished concrete transportation was assumed to be included in buying price. Because it can see how much maximum input cost the model was still profitable. RCA transportation was assumed to be on buyer site which was the normal practice in this process.
It was assumed as certain amount depending on machine capacity.
2.1.12 Other financial ratio
Debt to Equity ratio was assumed to be 1.5 which is the average rate that Bank was acceptable to approve the loan. Account receivable period: normally, a customer used the payment 30 days after delivery. Account Payable turnover period: normally, contractors, demolishers collected money instantly after a trade.
2.1.13 Other data
2.2 Input Parameters
Table 2 Input parameters for starting the simulation
2.3 Model Development
In this research tried to put the model more complicated by adding specific data of input of random variables and go with Monte Carlo 5 steps [ 24 ].
: Create a parametric model, y = f(x1, x2, ..., xq).
The model will calculate as the step of net profit computation.
The result of each row of calculation represents one month result.
The results are brought to create Income Statement, Cash flow statement and Balance Sheet.
Finally, 1.Payback period, 2. EBITDA per year/Initial investment 3.Profitability Index, 4.Internal rate of return (IRR), 5. Average Net profit and 6. Average unit cost, are computed from 3 financial tables [ 25 , 26 , 27 ].
: Generate a set of random inputs, xi1, xi2, ..., xiq.
Each Xiq is from Table 2.
: Evaluate the model and store the results as yi.
Store the 6 results; those are called 1 set of data.
: Repeat steps 2 and 3 for i = 1 to n.
n is set at 100 times per results.
: Analyze the results
After completion for one size of RCA plant in the first condition, a model will have set of data at selling price 0, 10,20, …, 100 baht per ton and buying price 180-80,190-90, 200-100 baht per ton; in total 33 sets of data were collected. (180 was selling price for coarse RCA and 80 was selling price for Fine RCA. Other couples are the same principle).
Then, only set of data at buying price 0 baht per ton and at Profitability Index about 1 will be used for analysis. Because buying price 0 baht can show the best performance of each model and Profitability Index about 1 can show the highest buying price that a model was still profitable.
After that, the other sizes and conditions will be calculated until obtaining all results from all models.
Finally, those data will be compared and find out advantages and disadvantages, and bring the best model to do a sensitivity analysis.
Fig. 8. Overall process for the model development.
Fig. 9. Example of data collecting and data picking for analysis
2.4 Sensitivity Analysis
Sensitivity analysis will be based on the situation which may be possible to happen.
In case the model showed the negative net profit, the results of many value will be tend to error due to the fact that cash flow is negative and the model is not assumed to borrow more money.
3. Results and Discussion
First: 100-ton-per-hour constant supplied plant.
From Table 3 , all measures of all selling prices showed impressive result. The higher selling price it was set, the higher return on investment it was. Besides, Payback periods were lower than 2.5 years which is not too long for an environmental project and does not bear a risk of technological change.
Table 3 Result of 100-ton-per-hour constant supplied plant.
Second: 50-ton-per-hour constant supplied plant.
From Table 4 , all measures of all selling prices showed impressive result. The higher selling price it was set, the higher return on investment it was. Payback periods were about 3 to 3.2 years which is not too long for an environmental project.
At Profitability index about 1 of both first and second models, Payback periods were higher than 5 years even other measures were in the acceptable values. Therefore, it is depended on a company’s strategy whether to accept it or not. Concerning to the environmental issue, it may be acceptable.
Table 4 Result of 50-ton-per-hour constant supplied plant.
Third: 100-ton-per-hour uncertain supplied plant
From Table 5 Profitability indexes were lower than 1, and besides, almost all results were malfunction due to the limitation of the negative net profit which the model did not set to invest more money in case it showed the negative profits; therefore, there were no cash for continued business, and the reason caused this was from the mismatch of supply (35 to 42 ton per hour) and machine capacity (100 ton per hour); therefore, revenue cannot fulfill the fix cost expense.
Table 5 Result of 100-ton-per-houruncertain supplied plant.
Fourth: 50-ton-per-hour uncertain supplied plant
From Table 6 , all measures of all selling prices showed fair result. The higher selling price it was set, the higher return on investment it was.
At buying price 0 baht per ton, profitability indexes were higher than 1.23 to 1.47 which. Payback periods were about 4 to 4.67 years which may be acceptable because of an environmental project.
Table 6 Result of 50-ton-per-hour uncertain supplied plant.
3.2 Model Comparison
Besides, the model can provide the probability of the trend which also can show in Histogram.
Fig 10 Histogram point of view comparing payback period of 4 methods at selling price 200 – 100 baht/ton
From Fig. 10 , Method 1, it was 100 percent that the payback periods were between 2 to 2.5 years. Method 2, it was 94 percent that the payback periods were between 3 to 3.5 years. Method 3, it was 52 percent that the payback periods were between 7 to 7.5 years. Method 4, it was 85 percent that the payback periods were between 4 to 4.5 years. Besides, the average value of payback period of each method was conformed to the majority population of its data.
From Table 7 , the best alternatives of each model were compared together in quantitative term. Almost all methods were survived except the method 3 due to the supply deficiency. Therefore, what is the enough supply to operate both models? This research did a simulation both RCA plant sizes to find out relation between buying prices and supplied volume that how much of supplied volume need to still generate Profitability Index about 1 which the result was shown in Fig. 11.
Table 7 Result comparison of 4 methods at selling price 200 –100 baht/ton.
Fig. 11. Average buying prices versus supplied volume at profitability about 1.
Finally, both models were compared the advantages and disadvantages in Table 8 .
Table 8 Advantages and disadvantages between 100 ton-per-hour plant and 50 ton-per-hour plant.
Considering into all methods, the method 4 the 50 ton-per-hour plant was the best alternative according to the assumption. Therefore, it was brought to do sensitivity analysis. In addition, Table 9, Table 10 , and Table 11 were examples of financial statement outputs from the simulation of 50 ton-per-hour plant.
Table 9. Income statement: 50 ton-per-hour plant under uncertain supply.
Table 9 Income statement: 50 ton-per-hour plant under uncertain supply
Table 10 Cash flow statement: 50 ton-per-hour plant under uncertain supply.
Table 11 Balance Sheet: 50 ton-per-hour plant under uncertain supply
3.3 Sensitivity Analysis
The 50 ton-per-hour plant was adjusted some parameters according to each condition. The objective is to find out the impact to Payback period reduction.
Fig. 12. Conditions of Sensitivity analysis
3.3.1 Cost impact
From 4 conditions, there were 2 groups can reduce Payback period which were total operating cost and investment cost.
In details of condition 1 to 3, it can show a linear relationship between operating cost reduction and impact of Payback period which formula of the relation was
Payback period = (-0.7144 x operating cost change) + 0.1168
From the equation, it can describe that every 1 million baht operating cost reduction per year can help the model have shorter Payback period 0.714 years.
In details of condition 4 when Interpolation was applied, we can assume that 3.421 million baht reduction can reduce Payback period -0.35 year; therefore
Every 1 million baht of investment reduction can help the model has shorter Payback period 0.102 years.
The ratio between investment reduction and cost reduction equaled 0.102:0.714 or 1: 7
Table 12 Impact of cost reduction of each condition to the financial ratio.
3.3.2 Revenue impact
Condition 5: Reduce the percent of Coarse RCA. Five simulations were computed in order to see the different impacting to the financial ratio which was shown in Table 13 .
Table 13 impact of coarse RCA output to the financial ratio.
In details of condition 5, it can show a linear relationship between percent of coarse RCA output, Revenue and Payback period. The formulas of the relation were
From the equation, it can describe that every 1 million baht of revenue can impact to the Payback period 0.488 year.
4. Conclusion and Recommendations
A big RCA plant (100 ton per hour, 52.77 million baht investment cost) was the best model because of shortest payback period (2.18 year), Highest Profitability index (2.6), Highest IRR (39.86%) and Highest net profit (21.34 million baht) at buying price 0 baht per ton and selling price 200 -100 baht per ton. Besides, it could accept maximum buying price to 80 baht per ton which leaded Profitability index about 1. However, a big RCA plant cannot survive under the uncertain supply as assumption (32.34 to 38.46 ton per hour) due to the profitability index below than 1. Nevertheless, to help the big RCA plant survive with Profitability Index about 1, supplied volume should have at least 42.5 ton per hour and buying price 0 baht ton. Another disadvantage was the fact that a big RCA plant needed larger area (2,000 square meters) to set up which may be difficult to find area in a city of Bangkok, meanwhile, a small plant needed smaller area (1,400 square meters).
A small RCA plant (50 ton per hour, 33.99 million baht investment cost) also showed good results but less performance than a big RCA plant. At buying price 0 baht per ton, Payback period was 3.01 years, Profitability index was 2.01, IRR 29.96% and net profit was 10.53 million baht. Besides, it could accept maximum buying price to 65 baht per ton. In performance term, the disadvantage was that it had a higher unit fix cost to operate a plant; because machine capacity was half of a big RCA plant, but its fix cost was reduced only 44.5%. However, the other advantage of a small RCA plant was that it could survive under the uncertain supply as assumption (32.34 to 38.46 ton per hour) with acceptable results. At buying price 0 baht per ton, Payback period was 4.05 years, Profitability index was 1.47and IRR 19.58%. Besides, it could accept maximum buying price to 40 baht per ton to make Profitability index about 1. However, a small RCA plant cannot survive when supplied volume was lower than 28 baht per ton.
Moreover, Both RCA plants had similar characters.
Finally, a small RCA plant was selected to be the proper plant for Bangkok under the uncertain supplied volume. The sensitivity analysis showed the relation among operating cost, investment cost and revenue impacting to the Payback period. In term of cost, in the same amount of cost reduction, change of operating cost could impact to Payback period higher than about 7 times to change of investment cost. In term of revenue, every 1% coarse RCA output change could impact to the revenue 0.124 million baht, and impact to the Payback period 0.06 year; therefore, every 1 million baht of revenue could impact to the Payback period 0.488 year.
In term of simulation, the model was built to have ability to show all of financial perspectives depending on investor point of view. Besides, by allowing to using random parameters, it made the model see a trend which helps investors analyze in another dimension. For example, in case we only do constant parameters, investing a big plant for reality may cause the investment failed due to lack of supplied volume.
Even though RCA is new for Thailand, it is a new opportunity to add value to the construction chain. The investor of RCA plant obtains profit from RCA business, the constructor gets the lower price of aggregate and it is a sustainable development for environment and besides this research did a simulation to proof that the RCA plant in Bangkok can make a profit. The small RCA plant was improved by sensitivity combination. However, there are many ways to improve the RCA business. For example,
As a big RCA plant is the best performance but due to deficiency supply causes it cannot do in Bangkok now. In fact, the demolished concrete is higher enough to run a big RCA plant, but owning to the dispersion of occurrence which makes the supplied volume low. If there is the system to ensure supplied volume of demolished concrete, a big RCA plant is possible to set up.
The RCA business model is related to ready mix concrete plant. If a ready mix concrete plant has an area to set up RCA plant, it will bring into great benefit. Indirect cost can be used together, investment cost is reduced, and transportation of RCA is shorter.
The model in simulation assumed that the RCA plant has to buy at least 0 baht per ton for demolished concrete. However, the RCA plant should obtain the money for demolished concrete disposal. This will lead revenue of a RCA plant higher. Therefore, if the government announces the law and enforce, this can improve the performance of RCA plant.
This study was supported by Faculty of Engineering, Kasetsart University.
- Concrete with Recycled Aggregates in International Codes Brito Jorgede, Saikia Nabajyoti. Recycled Aggregate in Concrete.2012;:379-429.
- Recycled Concrete And Demolition Waste Aggregate In Concrete Lloyd Natalie, List KatarinaVanDer, Re Natalie. Proceedings of the New Developments in Structural Engineering and Construction.2013.
- The Efficacy of Subgingivally Delivered Andrographis Paniculata Gel to Treat Patients with Periodontitis Teparat-Burana Thitiwan, Samarnsotthiwong andChalita, Kasetsuwan Julalux, Sirirat Mullika, Rojanapanthu Pleumchitt. Journal of Research and Practice in Dentistry.2015-apr;:1-14.
- InthataSomchai CheerarotRaungrut Computers and Concrete.;:17-30.
- Study of recycled concrete aggregate quality and its relationship with recycled concrete compressive strength using database analysis González-Fonteboa B, González-Taboada I, Martínez-Abella F, Carro-López D. Materiales de Construcción.2016-jun.
- Power System Control Experiences And Future Perspective Cegrell T. Proceedings. Joint International Power Conference Athens Power Tech,..
- Recycling Concrete Debris from Construction and Demolition Waste Ganiron TomasUJr. International Journal of Advanced Science and Technology.2015-apr;:7-24.
- A model for assessing the economic viability of construction and demolition waste recycling—the case of Ireland Duran Xavier, Lenihan Helena, O’Regan Bernadette. Resources, Conservation and Recycling.2006-mar;:302-320.
- Evaluation of the economic feasibility for the recycling of construction and demolition waste in China—The case of Chongqing Zhao W, Leeftink RB, Rotter VS. Resources, Conservation and Recycling.2010-apr;:377-389.
- Statistical analysis of recycled aggregates derived from different sources for sub-base applications Barbudo A, Agrela F, Ayuso J, Jiménez JR, Poon CS. Construction and Building Materials.2012-mar;:129-138.
- A Framework for Construction Labor Productivity Improvement in Egypt El-Batreek AhmedH, Ezeldin AhmedS, Elbarkouky MohamedMG. AEI 2013.2013.
- Rothmannia macrophylla (Rubiaceae), a new record for Thailand KHAMMONGKOL KWANJAI, CHAMCHUMROON andVORADOL, TETSANA NAIYANA, POOPATH MANOP, WAI JAREARNSAKSAE, SUNGKAEW SARAWOOD, and Thai Forest Bulletin (Botany).2016;:32-34.
- CPI: all items ..
- The pleurophocercous cercariae infection in snail Family Thiaridae Grey, 1847 Northern, Thailand Chontananarth Thapana, Wongsawad andChalobol, and Asian Pacific Journal of Tropical Disease.2017-apr;:205-210.
- IRS makes Form 1023-EZ data available online Nonprofit Business Advisor.2017-may;:1-1.
- Search Engine Optimization for Crowdfunding Platform (Donation & Reward) July 11-12, 2017 Bangkok (Thailand) Back LHHISS-17, FCBHS-17, ASET-17.2017.
- A new species of Abutilon (Malvaceae-Malvoideae) from Thailand PHUPHATHANAPHONG LEENA. Thai Forest Bulletin (Botany).2016;:45-48.
- Key statistics on diaspora from Thailand .2012-oct.
- The Process of Commonwealth Budgetary Control Keating Michael. Budgetary Management and Control.1990;:1-16.
- The Process of Commonwealth Budgetary Control Keating Michael. Budgetary Management and Control.1990;:1-16.
- eService eDemocracy & eGovernment.;:61-85.
- Treasury Department Treasury Management.2011;:1-19.
- Investigation of factors affecting a construction waste recycling decision Chinda Thanwadee. Civil Engineering and Environmental Systems.2016-mar;:214-226.
- On the magnetic ordering in interleaved Fe(3 ML)/V(yML)/Fe(2 ML)/V(yML) superlattices Eftimova K, Blixt AM, rvarsson BHj, Svedlindh P. Journal of Physics: Condensed Matter.2002-nov;:12575-12583.
- Use of Farm Financial Statements in Illinois Frey ThomasL. Illinois Agricultural Economics.1975-jul.
- Biases in Analysts\textquotesingle Multiyear Forecasted Income Statements, Balance Sheets, and Cash Flow Statements Hand JohnRM, Martin Nicholas. SSRN Electronic Journal.2017.
- Show Me the ROI! Data-Driven Marketing.2015;:104-133.