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Self‐healing concrete A concrete solution for a concrete problem Imagine Ruben Boelens Self‐healing concrete Jeroen Goedhart Dr. Henk Jonkers Stijn Jagers TU delft Roel Oldenkamp February 2012 RSG Pantarijn, Wageningen


Acknowledgements Without the help of others we would never have got this result. First we would like to thank two teachers of Pantarijn. Arthur Roosen, our biology teacher, helped us to set up an experiment. Han Dijkstra, our English teacher, corrected the English text several times. We would also like to thank Gerben Gerbrandy, who works on irrigation systems in Ecuador. He provided us with a lot of information about irrigation canal Cruzsacha and the area surrounding this canal. Our parents have made a lot of suggestions to improve our business plan, so we want to thank them too. Finally, we wish to thank Dr. Henk Jonkers and Virginie Wiktor, our scientists. They answered a lot of questions about self‐healing concrete and also helped us when setting up the experiment. At the kick‐off of Imagine, scientists were said to be extremely busy people. A reply to an e‐mail might take a long time. Maybe our scientists were not busy at the moment, because they answered all our e‐mails very quickly. We appreciate this very much.


Introduction

We are four students from secondary school RSG Pantarijn in Wageningen. We were introduced to Imagine by a group of students from RSG Pantarijn who participated in Imagine last year. We were immediately very enthusiastic about Imagine and decided to join the contest. The project we have chosen is on the subject of self‐healing concrete. We chose this project because we think it is the project in which we are most free to come up with our own ideas.

The low level of the sustainability of concrete is a worldwide problem. This is often caused by cracks in the concrete. When cracks appear, the quality of the concrete will deteriorate due to water leakage and corrosion. The concrete becomes weak and there is a high risk of collapse, so parts of the concrete construction often need replacing. In highly‐developed countries, there is enough money to replace concrete when it becomes too weak. However, in developing countries there are fewer funds available to repair or replace concrete. Concrete structures may be neglected and the weakness of these constructions in developing countries can become a danger to its population or the environment. TU Delft have now developed a new technique, self‐healing concrete, which can probably solve the problem illustrated above. Self‐healing concrete is a normal concrete mixture, with the addition of bacteria and nutrients, which can fill cracks by itself. When cracks appear, the bacteria will produce limestone, which fills the cracks. This self‐healing concrete now possesses the quality to repair itself and thus increase the sustainability of concrete. Consequently, this concept will save a lot of money.

The technique also seems to be very appropriate for the development and maintenance of irrigation systems worldwide. When there is a lack of rain, irrigation is the only way to maintain the production of crops. We would like to apply self‐healing concrete to reconstruct part of the Cruzsacha canal, in the Andean highlands of Ecuador. Irrigation canals are often cracked, which results in a large amount of leakage putting in danger the sustainability of the canal, which may even result in the collapse of the entire irrigation and food production system of the local communities. The application of self‐healing concrete will improve sustainability and reduce the costs of maintenance and restoration.

Our project comprises two stages. The first stage is to investigate whether self‐healing concrete can be applied to irrigation canals. We would therefore like to perform an experiment in Ecuador. Since self‐healing concrete is a relatively new technique, it is important to gather more results before applying self‐healing concrete on a bigger scale. The second stage is a business plan. In this business plan we describe how we intend to apply self‐healing concrete to the Cruzsacha canal.


Index Acknowledgements 2 Introduction 3 Index 4 Global overview of the situation in Ecuador 5

‐ Why Ecuador . ‐ Geography . ‐ Economy . ‐ Demography . ‐ Government .

Global overview of the situation in National Park Llangates 6 ‐ Why the Cruzsacha canal . ‐ Geography . ‐ Demography . ‐ Agriculture . ‐ Infrastructure . ‐ Irrigation systems in Ecuador . ‐ The Cruzsacha canal .

The technique of self‐healing concrete 8 ‐ Why irrigation systems .

Experiment at Cruzsacha in Ecuador 10 ‐ Research question . ‐ Hypothesis . ‐ Measurement set‐up . ‐ Results . ‐ Costs experiment .

Business Plan 13 ‐ Our product . ‐ Costumers . ‐ Key partners . ‐ Transport .

Costs business plan 14 ‐ Costs of 500 metres Cruzsacha . ‐ Price determination . ‐ Irrigation canals in general .

Conclusion 16 Sources 16 Appendix 17 ‐ 21 Experiment at TU Delft 22


Global overview of the situation in Ecuador

Why Ecuador We had to find a country with a lot of irrigation canals for which this self‐healing concrete may be a solution to their leakage problem. People, who have to deal with conflicts and war, are not in need of self‐healing concrete, because their first concern is safety. People in these countries have other concerns than self‐healing concrete. Therefore we had to think of a country with an economy steady enough to provide the primary support to solve the needs of its population. Only then they can invest in the realisation of this project. We immediately thought about countries in South America. Most South American countries can tackle the primary needs of its people and a lot of irrigation canals are situated in South America.

Having good local contacts is a prerequisite for the experimental field study we have in mind. Rutgerd Boelens told us about such a good local contact: Gerben Gerbrandy. He is a Dutch scientist, who works on irrigation systems development in Ecuador. So the choice of Ecuador was an easy one. By good contacts it is a lot easier to set up an experiment and to apply self‐healing concrete to irrigation systems. Geography Ecuador is situated on the equator. Its capital is Quito. Ecuador has acreage of 280,000 m2. Ecuador has three major ecological regions with different climates, landscapes plants and animals. The first region is called the Costa. This has a coastal climate and landscape. The Costa contains part of the big river Rio Guayas. This area also has forests and hills. The second region is called the Sierra. These are highlands between two mountain chains of the Andes. The third region is called the Oriente, also known as the Amazon tropical rain forest. The Galapagos Islands are also part of Ecuador.

Economy The monetary unit of Ecuador is the American dollar. The most important part of the economy of Ecuador is crude oil. Twelve percent of the landscape of Ecuador is agriculture. Important export products are bananas, cacao and coffee. The GDP of Ecuador is 58.91 billion American dollars. The export of Ecuador is thirty one percent of the GDP. Demography The population of Ecuador is circa 15 million inhabitants. 30.1 percent are under fourteen, 63.5 percent between 15 and 64 and 6.4 percent over 65. The population grows at a percentage of 1.4 percent each year. The mestizos (descendants of mixed Spanish/indigenous couples) are the largest group in Ecuador. 65 percent of the population are mestizos. 10 percent of the population are descendants from white Spaniards or Africans. 25 percent are Indian.

Government Ecuador is a republic and it has been independent from Spain since May 24, 1830. Head of state is Rafael Correa who won the 2006 elections.

http://www.nationmaster.com/country/ec‐ecuador


Global overview of the situation in National Park Llanganates Why the Cruzsacha canal In Ecuador there are many irrigation canals. We chose the Cruzsacha canal, because there is a clear need to find maintenance solutions for the concrete structures, and because Gerben Gerbrandy is working at this canal at the moment. It will be a lot easier to test self‐healing concrete at this canal. Some parts of the canal have to be replaced and self‐healing concrete can be used for these parts.

Geography The irrigation canal to which we would like apply our technique is called Cruzsacha. Cruzsacha is situated in the National Park Llanganates1. This National Park, which has land in the Cotopaxi , Napo, Pastaza and Tungurahua Provinces, is a protected area in Ecuador. It is well‐known for its diversity of wildlife and nature. This large diversity is a consequence of big differences in altitude within the National Park (2200‐4400 metres above sea level).

Demography The Cruzsacha canal provides irrigation water to 7 communities, 410 families. The people living in these communities are poor peasants. They have an indigenous (Indian) identity and culture. In the past they and their ancestors were farm workers, working for large landowners. The irrigation canal has not been used for about 30 years and now the water rights of the canal and the ownership of the land have passed on from the landowners to the Indian farm workers.

Agriculture The peasants mainly use subsistence agriculture. This means that they focus on growing food for their own supply. The surplus will be sold in the local market place. The Cruzsacha canal is responsible for the irrigation of 410 ha of farmland. A large variety of crops are grown on these lands. Appendix B2 shows a table of one of the two main areas that are irrigated by the Cruzsacha canal. The second main area is very similar to the first. As can be observed, the main crops are grown in meadows. These meadows produce cattle feed, not only grass but also other species, like clover and alfalfa. It can also be concluded that most of the crops that are grown need to be irrigated. Remarkable is the low cropping intensity, only 8 percent of the lands have 2 harvests a year. It is not water requirements, but the low temperature and especially the frost periods that lead to severe limitations. Infrastructure The Cruzsacha canal is situated in a poorly developed area. The mountains and the large numbers of water flows make it hard to construct good access roads. Besides, the canal is situated in a protected area, which makes construction even harder. To picture an image: travelling by car you can only get to the canal as close as 12 km, so you have to walk at least 12 km to reach the canal.

Irrigation systems in Ecuador Irrigation systems have been used for a very long time, also in Ecuador. The Incas, who lived in Ecuador from about 1438 A.D. till 1532 A.D., took the quality of the irrigation systems to a very high level. The Incas were famous for their great architecture. They were able to build bigger and better irrigation systems, replacing many earthen irrigation canals by new ones made of carefully shaped stones and rock cutting. After the conquest of the Inca empire, the Spaniards used the same irrigation techniques and systems as the Incas.

Early 20th century, modern irrigation systems, designed by skilled engineers, were introduced. They started using concrete for lining the canals. Parts of old irrigation systems were replaced by new ones, just as the Cruzsacha Canal.

Most irrigation systems are similar. They consist of a main canal, a secondary canal and tertiary canals. The highest point of the main canal, where the water from the river or springs is led into the canal, is called the intake. The secondary canals are branches of the main canal. The secondary canals do not provide the lands with water; this is

1 Appendix A: Map of the Llanganates National Park

2 Appendix B: Table of grown crops at the Cruzsacha canal


the function of the tertiary canals. They lead the water to a piece of land cultivated by several farmers. They can irrigate their lands by rotating, each farmer according to his turn.

The Cruzsacha Canal3 The Cruzsacha is an irrigation canal with the length of 19 kilometers. It starts at a height of 4100 meters above sea level and ends at a height of 3800 meters above sea level. The daily air temperature will vary between ± ‐5 and +15 degrees, because of the different heights and difference between day and night.

3 Appendix C: Measurements of the canal

Photo Cruzsacha, 2011


The technique of self‐healing concrete

Concrete is made of cement, usually Portland cement, water and other filling materials, like sand and grit. The concrete hardens after mixing with water, which will take about one month, because the cement hydrates with water.

Microcracks in the concrete are an inevitable feature of ordinary concrete, because of the tensile strength. The tensile strength increases when there are a lot of temperature differences. These microcracks reduce the durability of the concrete structure. Under certain circumstances, small cracks in ordinary concrete can heal themselves. When the mixture hardens, not every cement molecule reacts with water. The non‐reacting cement molecules can react with water, which flows in the concrete because of the cracks [1]. Limestone will be produced, which fills the cracks. Ordinary concrete is able to heal cracks of a width of circa 0.20 mm4. If cracks become larger, the concrete will not be able to heal these cracks.

Recently, in experiments, bacterial spores and nutrients and calcium lactate have been used as self‐healing agents. The bacteria and calcium lactate are both embedded in capsules, to prevent interaction before cracks appear. Concrete with added healing agents is called self‐healing concrete. The addition of those capsules will change the composition of the mixture, because part of the mixture has to be replaced by the healing agent. Per cubic metre concrete, 15 kg healing agent has to be added, which means that 15 kg cubic metre concrete material has to be removed. This will decrease the strength of the concrete.2 There are several useable bacteria which can be added to the concrete. Usually, the Bacillus alkalinitrulicus, an alkali‐resistant soil bacterium, is added. Alkali‐resistant bacteria live in extreme alkaline circumstances. Ph‐values range from 9 to 11. Their temperature range reaches from 10 till 40 degrees Celsius. There is another possible bacterium which can be added. This is a psychrophilic bacterium. This bacterium also lives in extreme circumstances with the same pH range but an optimum temperature close to freezing point. The bacteria are added to the concrete mixture as spores. Spores are inactive cells with a high survival rate. They are proof against unfavourable circumstances like temperature fluctuation and moisture. The spores become active when getting into contact with water. When the alkali‐bacteria grow active, they can make limestone out of calcium lactate [2]. When the living conditions become unfavourable again, the active bacteria will form spores.

The added capsules tear open when cracks appear in the self‐healing concrete. Water will leak inside, which will activate the bacteria. The bacteria, which will be in contact with the released nutrient, calcium lactate, will produce limestone. Limestone will fill the cracks and there is no possibility for water to leak into the concrete anymore. These bacteria are able to heal cracks of a width of 0.80 mm within circa 100 days5. After filling the cracks, the circumstances will turn unfavourable again so the bacteria will form spores again. 5CO2 + 5Ca(OH)2 5CaCO3 + 5H2O [1] Carbon Dioxide + Calcium Hydroxide Limestone + Water

Ca(C3H5O2)2 + 7O2 CaCO3 + 5CO2 + 5H2O [2] Calcium Lactate + Oxygen Limestone + Carbon Dioxide + Water

Why irrigation systems Concrete is the most used construction material worldwide. There are many possibilities of applying self‐healing concrete in everyday constructions, like bridges and buildings. These applications of self‐healing concrete seemed to

4 Appendix D: Results of experiment with self‐healing concrete


Betoniek. Hoera mijn beton klust zelf 24, 2009


us to be more compatible with higher‐developed countries than to developing countries, so we started thinking of other self‐healing concrete applications.

Rutgerd Boelens, Ruben’s father, made the suggestion to use self‐healing concrete to construct irrigation systems in South America. We realised that the self‐healing characteristics of this new technique would be a good addition to concrete used for irrigation canals nowadays. Irrigation systems made of concrete sometimes suffer from cracks and so water loss is caused. Even small cracks in the concrete can cause a significant amount of water loss. By using self‐healing concrete these cracks will be repaired by the concrete itself and water loss will be reduced.

The Ecuadorian irrigation systems are often situated in remote areas. When irrigation systems are damaged they are often barely accessible to people to repair them, and it is difficult and costly to get repair materials to the precise areas. Also, small types of damage, like cracks, are often hard to find, because these canals are usually several kilometres long. This makes repairing irrigation canals a difficult and expensive process. By using self‐healing concrete people do not have to go to the damaged places as often as with the ordinary concrete.

Another advantage of applying self‐healing concrete to irrigation canals is the fact that the bacteria in self‐healing concrete will be in direct contact with water. In the previous chapter it was explained that water is necessary for bacteria to become activated. Most of the time, there is water in the canals, so when the concrete gets cracked the bacteria will immediately be activated.

A disadvantage of self‐healing concrete is the replacement of a relatively strong ingredient of concrete with a relatively weak ingredient, namely the self‐healing agent. Therefore the concrete will lose strength. By applying the self‐healing concrete to irrigation canals this disadvantage will not play a role. The main function of irrigation canals, the transport of water, will not exert a lot of pressure on the concrete. The loss of strength will not influence its function. When you apply the self‐healing concrete to, for example, a wall, this drawback may cause a strength problem.

The self‐healing quality of concrete will make the concrete canals more durable. Consequently, there will be fewer repairs and it will take longer before replacement is required. Therefore the costs of maintenance when using self‐healing concrete will be lower than when ordinary concrete is used.


Experiment at Cruzsacha in Ecuador

So far, self‐healing concrete has been tested in the lab, but not yet in the field. Before releasing the application of self‐healing concrete to irrigation canals in Ecuador, we have to test the new technique, otherwise there is a possibility that the self‐healing concrete will not work well in Ecuador. We want to make sure self‐healing concrete can be used. By performing an experiment at the Cruzsacha canal, we intend to realise this. The water temperature of the irrigation canals (melt water from the mountains’ ice caps) varies from 2 to 5 degrees Celsius, while tested alkali‐bacteria have a temperature range from 10 to 40 degrees Celsius. This means that the alkali‐bacteria will not show any activity. We have to use psychrophilic bacteria for our project, because their optimal temperature is lower, around freezing point. Psychrophilic bacteria have the same characteristics as alkali‐bacteria, but the psychrophilic bacteria have not been tested in the lab yet. The costs of our experiment in Ecuador are low, so we think that it is not necessary to do a lab test previous to a field test.

Research question What is the difference in leakage between self‐healing concrete and the presently used concrete of the Cruzsacha canal?

Hypothesis We expect the degree of leakage to be lower in the self‐healing concrete than in the presently used concrete. This prediction is based on lab results6 of tests with alkali‐bacteria. We think the use of psychrophilic bacteria, which have not been tested in the lab, will make no difference. These results confirm that the bacteria can fill cracks in concrete with limestone and reduce its leakage.

Measurement set‐up In the experiment it is very important to imitate reality. The circumstances of the tested concrete have to be the same as the concrete used in the irrigation canals. Only if the circumstances are the same, we will be able to make a good comparison. Therefore the experiment has to meet three requirements:

1. The irrigation water has to flow over the self‐healing concrete during the self‐healing process of the bacteria and the concrete itself.

2. The water temperature has to be identical to the water temperature in the irrigation canals. 3. The composition7 of the concrete mixtures of the irrigation canal and the tested concrete have to be the

same.

Our experiment comprises four steps:

1. making two types of concrete discs 2. breaking concrete 3. measuring leakage 4. placing concrete in the canal 5. measuring leakage after curing period.


7 Appendix E: Composition of the concrete used at the Cruzsacha canal


1. Making two types of concrete Two different types of concrete have to be made. Type 1: Presently used concrete. The concrete has the same mixture composition as the irrigation canal concrete8. Type 2: Self‐healing concrete. The concrete has the same mixture composition as the irrigation canal concrete, but healing agent is added to the concrete. Our healing agent consists of the nutrient calcium lactate and the psychrophilic bacteria.

We have to use psychrophilic bacteria, because the water temperature of the irrigation canals varies from 2 to 5 degrees Celsius, while tested alkali‐bacteria have a temperature range from 10 to 40 degrees Celsius. This means the alkali‐bacteria will not show any activity. The two types of discs have the same dimension.

Dimensions of the discs

Diameter 18 cm

Thickness 2 cm

Volume 509 cm³

Preparation and materials9 2.Breaking the concrete Before depositing the concrete discs in the canal, they have to be broken and glued. If you do not break the discs before depositing them in the canal it will probably take years before leakage cracks appear. By breaking the concrete the bacteria will be activated immediately, so we will have our results sooner. When the concrete is broken, the separate parts are glued together. It will take 2 days for the glue to dry.

3. Measuring the leakage Water percolation test: fill Ø 18 cm bucket containing the concrete disc with 5L water. Measure the amount of water percolating through disc in 1 hour period.

4. Placing concrete in the canal When all discs have been made and the amount of leakage has been measured, the discs have to be put in the canal. The heavy weight of the discs will ensure that the discs will not wash away with the stream. It is not necessary to attach the discs to the canal. 5. Measuring leakage after curing period After a period of three months (twelve weeks), we will remove the discs from the water. By this time the self‐healing bacteria should have done their work, filling the cracks with lime. We will repeat the measurement method (see the third step) and compare the results.

8 Appendix E: Composition of the concrete used at the Cruzsacha canal

9 Appendix F: Preparation and materials needed for experiment


Results When we have all the results, we have to assimilate these in tables10.

Costs experiment11

Item (project contributions)

Unit Quantity Cost/unit (euro) Total costs (euro)

Bag cement ‐ 1 10 10

Self‐healing agent kg 5 1 5

Concrete mixer(rent) ‐ 1 30 30

Bucket ‐ 80 2 160

Concrete vibrator(rent) ‐ 1 30 30

Local materials as grit and sand will be acquired from local river banks. A local lorry will take care of transportation.

Item(local contributions)

Unit Quantity Cost/unit (euro) Total costs (euro)

Grit and sand (including transport: overall costs)

‐ ‐ 20 20

Total 255

10 Appendix G: Empty table for the results

11 Appendix H: Calculation of costs experiment


Business plan

Introduction After analysing the results of our experiment and if the results are promising, we will start the second stage. We will supply the self‐healing agent to our customers, so that it can be used for the construction of irrigation canals. We would like to apply our product to 0.5 km of the Cruzsacha canal, so we wrote a business plan that includes all that is needed to realise this project.

Our product The product that we are going to deliver is the self‐healing agent accompanied with instructions. The self‐healing agent will be supplied as a separate product just like the other ingredients of the concrete, so we will not supply the agent mixed with grit. Providing the agent and the concrete ingredient together in one mixture is not possible, because the self‐healing agent has to be put in the concrete mix at the very end. If not, the self‐healing agent will be damaged during the mixing process. Besides, not all concrete mixtures are the same. For different projects and constructions you will probably use different concrete mixtures. So for these reasons we will supply weighed portions of the agent in bags. We think self‐healing concrete is very useful for the farmers. The costs of buying the self‐healing agent are relatively low and by using this agent the lifetime of the concrete will increase. Consequently, the self‐healing concrete irrigation system will not have to be replaced as often as an irrigation system made of ordinary concrete and so, eventually, using the self‐healing agent will save money. Self‐healing concrete will also take away part of the maintenance and restoration activities and costs. Apart from lower costs and the reduction of restoration activities, self‐healing concrete is, thanks to its greater durability, better for the environment. We intend to deliver an amount of self‐healing agent that is enough to build 0.5 km of the Cruzsacha canal. For this we need 2.175 m3 self‐healing agent12. As we are going to provide a new kind of product on a non‐profit basis, it is unlikely that there will be competition from other companies.

Customers Our customers are the farmers living near the Cruzsacha canal. Their life depends on agriculture, which is made possible by irrigation water from the Cruzsacha canal. Irrigation systems are a large and expensive investment, so farmers are not able to pay the costs all by themselves. The Cruzsacha canal is partly subsidised by a charity fund of the German Bank KfW and the German government. The finance of the canal is more or less a cofinancing between the KfW bank, the Ecuadorian Government and the farmers.

Key partners Apart from our customers (the farmers), we have two key partners: the KfW Bank that provides irrigation development support to the farmer communities, and the factory that manufactures the self‐healing agent. Scientists from TU Delft are developing a way to manufacture the self‐healing agent on a large scale. Within a year a factory will be set up, which will produce the self‐healing agent on a larger scale.

Transport The self‐healing agent has to be transported to Ecuador. In total we will have to transport 2.175 m3 = 3262.5 kg of the self‐healing agent13. For this amount, shipping seems the best method of transport. There are several companies that ship goods from Rotterdam Port to the Guayaquil Harbour in Ecuador. From Guayaquil harbour the self‐healing agent will be transported to the Llanganates National Park by lorry. We will have to rent a lorry and a driver for 1 day.




Costs of Business plan In this chapter we quantify costs and profits. First we make an outline of costs of our business plan. The second part is the calculation of the price of self‐healing concrete. Last, we made a calculation about when the application of self‐healing concrete is profitable on the long‐term

Cost for 500 metres Cruzsacha For applying the self‐healing agent to the Cruzsacha canal we have the costs of the self‐healing agent and the costs for transport. We only supply the self‐healing agent, so the costs of machinery and employees are not relevant.

Item Unit Quantity Cost (€)/Unit Total Cost (€)

Self‐healing agent m3 2.175 1,500 3,263

Transport by ship(minimum price per m3, NL to Guayaquil) m3 1 354 822

Transport by lorry(minimum price per m3 Guayaquil to Cruzsacha) m3 1 250 250

Training workshop for project employees and community leaders about use of self‐healing agent days 1 250 250

total 4585

Price determination Our project is based on developing help, so it is a non‐profit project. The price of the self‐healing agent is calculated by covering all costs (see table). We sell the self‐healing agent per kg. The selling price per kg will be the total costs divided by the number of kg of the self‐healing agent: 4585/2175 = €2.11 per kg self‐healing agent. For one m3

concrete one has to add 15 kg self‐healing agent, which costs 15*€2.11 = €31.65. When is self‐healing concrete lucrative This section contains a mathematical comparison, with which one can calculate whether the use of self‐healing concrete or the use of ordinary concrete is most advantageous in terms of costs and profits. This comparison can be used for every irrigation canal.

We would like to compare all cost per m3 concrete per year (m3/year) of ordinary concrete and self‐healing concrete. The price of self‐healing concrete is higher because of the addition and transport of the self‐healing agent. However, the lifetime of the self‐healing concrete will increase. By comparing the costs per m3 per year of both types of concrete, we can calculate at which costs per m3 concrete or at which lifetime increase the costs of both types are exactly the same. We do not take interest rates or depreciation into account. Define the following symbols:

C = All cost, including material and labor, of ordinary concrete (€/m3) Y = lifetime ordinary concrete in years T = Price of self‐healing concrete (see price determination) (€/m3) = 15*€2.11 = €31.65 Q = the increase of lifetime by using self‐healing concrete as index figure.

The cost per year of ordinary concrete is C/Y and the cost per year of self‐healing concrete is (C+T)/(QY). In our project (C+31.65)/(QY). Equating these two costs yields 31.65 = (Q‐1)C. So when the price T (=€31.65) is less than (Q‐1)C, it is advantageous to use self‐healing concrete. The equation can also be written as Q = (C+T)/C. In our project Q = (C+31.65)/C. So when the lifetime factor Q is larger than (31.65+C)/C it is also beneficial to use self‐healing concrete. Note that since T is only the extra cost of material and transport, T will be much smaller than C and so (T+C)/C will be close to one. This implies that even with a small lifetime factor Q, self‐healing concrete is cheaper in the long run.

This comparison is very useful for our customers. This formula contains only two unknown aspects. If we know one of those we can calculate, for example, at which increase of lifetime (Q) the costs for using self‐healing concrete or for using ordinary concrete are exactly the same.


Now we fill in the information of the Cruzsacha canal in the comparison. We know C, so we can calculate at which increase of lifetime (Q) the costs of both types of concrete are the same. C = total costs irrigation canal/ total amount of m3 concrete = €182,995.8214/1,523.27= €119.5. Filling in C in (31.65+C)/C = Q you will get Q= 1.265, which means the healing percentage of our self‐healing concrete has to be 26.5%. An increase of this Q will led to fewer costs by using self‐healing concrete than by using ordinary concrete. This Q has to be determined by our described experiment. In lab tests it was found that Q is in the range 20% ‐ 30%. Apart from the profits due to the life‐time increase, there will also be profits because of the decrease of reparation costs. It is thus likely that the use of self‐healing concrete will save money in the long run.

14 Appendix I: Costs Cruzsacha canal


Conclusion At the start of this project, our main goal was to invent a way to apply self‐healing concrete. Our aim was to help the farmers with their leakage‐problems of concrete. Our hopes are, however, that if this project will succeed, self‐healing concrete can be applied to a larger scale, so more irrigation canals will consist of self‐healing concrete. It gives the local people a better opportunity to irrigate their fields. We have high hopes self‐healing concrete will be sponsored by concrete‐companies in the future, because of the low application costs. Besides, self‐healing concrete creates a better environment, because it needs fewer reparations.

We enjoyed writing this business plan and we are satisfied with the final result. We really think our business plan is a concrete solution for a concrete problem.

Sources

Institutions TU Delft, Netherlands KfW, bank in Germany Literature Betoniek, 2009. ‘Hoera mijn beton klust zelf’. Betoniek 14‐24: p. 1‐10 Wiktor, V., and Jonkers, H.M., 2011. ‘Quantification of crack‐healing in novelbacteria‐based self‐healing concrete’ Cement & Concrete Composites 33(2011) p.763‐ 770 de Muynck, W., de Belie, N., Verstraete, W., 2010. ‘Microbial carbonate precipitation in construction materials: A review’ Ecological Engineering 36 (2010) p.118‐136 Yoder, R. (Ed.) 1994. Designing Irrigation Structures for Mountainous Environments: A handbook of experiences. Colombo, Sri Lanka: International Irrigation Management Institute (IIMI). Xviii, 206p. Boelens, R. 2008. The rules of the game and the game of the rules. Normalization and resistance in Andean water control. Wageningen, The Netherlands: Wageningen University.

Websites www.allez‐allier.com www.baggage.nl www.birdlife.org www.chalinga.nl www.ecuador.com www.engineer.co.uk www.indexmundi.com www.polymetaal.nl www.unstats.un.org www.wikipedia.org www.wereldreisgids.nl

Companies Worldwide Baggage and Packages, Netherlands Persons Rutgerd Boelens Han Dijkstra Gerben Gerbrandy Henk Jonkers Arthur Roosen Virginie Wiktor


Appendix

Appendix A: Map of the Llanganates National Park


Appendix B: Table of grown crops at the Cruzsacha canal

Crops pattern Andahualo

Crops

ha %

1 year old plants

Maize corn1 5 2

Potato1 5 2

Maize corn2 10 4

Potato2 12 5

Fieldbean2 4 2

Maize stalk2 5 2

Vegetables2 5 2

Grassland2 5 2

Second harvest crops

Grasland2 10 4

Field bean and pea2 10 4

Permanently corps

Grassland1 39 16

Grassland2 152 63

Not irrigated crops 49 20

Irrigated crops 213 88

Total irrigation area 193 80

Total cultivated area 262 108

Fallow (not cultivated) 0 0

Total area 242 100

Land use intensity 1.08

In this table you see the different crops that are cultivated and the respective area they occupy in hectares.

1 = not irrigated 2 = irrigated


Appendix C: Measurements of the canal

Measurements Cruzsacha canal

1,20

0,15 0,90 0,15

0.90 1,05

0,15

0,15

0,70 0,15

1,00

The surface area of the canal is: 0.435 m2. The total volume of 500 metre Cruzsacha canal is 500*0.435 = 217.5 m3. For 1 m3 concrete 10L self‐healing agent is needed. In total 217.5*10/1000 = 2.175 m3 is needed to make 500 metre self‐healing concrete. 1L self‐healing agent weights 1.5 kg, so in total 3,262.5 kg self‐healing agent is needed.

Appendix D: results of experiment with self‐healing concrete


Appendix E: Composition of the concrete used at the Cruzsacha canal Composition of the concrete used at the Cruzsacha canal ‐ Per m3 concrete mixture there is needed: Sand (sieve N°100 en N° 4) = 0.58 m3 Grit (½" tot 1") = 0.72 m3 Portland cement type I = 313 kg Water = 0.2035 m3,

Appendix F: Preparation and materials needed for experiment Bring all ingredients together (see materials for these ingredients). Stir the mixture using a concrete mixer afterwards. When making self‐healing concrete, the self‐healing agent will be added to the mixture after mixing, otherwise the capsules will break, and the self‐healing agent will not work anymore. Carefully oil each bucket, otherwise the concrete will adhere. Put the mixture into a bucket with a diameter of 18 cm and mark the buckets (type 1 or type 2). Vibrate the mixture for 15 seconds to make sure all the air bubbles are gone and to make the concrete smooth. Fix a lid on each bucket and cure the mixture for three weeks. We will make 80 discs, 40 discs of ordinary concrete and 40 discs of self‐healing concrete, so we have to make a total of 80 discs. ‐ 41L concrete mixture ‐ Self‐healing agent (in capsules), 5 Kg ‐ 80 buckets (+ lid) with a diameter of 18 cm ‐ Oil ‐ A concrete mixer

Appendix G: Empty table for the results

measurements

"raw" results "processed"

sample name

start time

time when empty

weight after 1 hour

sample name

time to empty

water permeated

[min] [min] [g] [min] [mL] subtracted:

ml/min

Control 1 0 Control 1

Control 2 +1 Control 2





Bacteria 1 +6 Bacteria 1







Appendix H: Calculation of costs experiment

We make 80 discs. Each disc has a volume of 0.509L, so in total we need 80*0.509L = 40.72L concrete. The cost for 1m3 concrete used for Cruzsacha is 82.5 euro (source: project document ; USD 112). The costs for 40.72L (0.0407m3) concrete are 82.5*0.0407 = 3.36 euro. However, minimum amounts of cement to be acquired commercially = 1 bag = 10 Euros.

The self‐healing agent is added in 40 discs so we need to add the self‐healing agent to 40*0.509L = 20.4L (0.0204m3) concrete. Per m3 concrete 15 kg self‐healing agent is needed. This means that 0.0204*15 = 0.306 kg self‐healing agent is needed. The price of 1 kg self‐healing agent costs 1 euro, so the costs of the self‐healing agent will be 0.31 euro. To account for several trials, however, we will bring with us 5 kg; costs = 5 euro. Appendix I: Costs Cruzsacha canal

RUBRO UNIDAD CANTIDAD P/UNIT. P/TOTAL

Revestimiento integral de canal (3502 metros)

.‐ Desbroce y limpieza (Cleaning) m2. 5253,00 2,19 11504,07

.‐ Nivelación y replanteo (Canal mapping) ml. 3502,00 0,17 595,34

.‐ Excavación a mano (Canal digging) m3. 1575,90 2,92 4601,63

.‐ Relleno compactado (Filling and compacting of concrete) m3. 1575,90 3,78 5956,90

.‐ Hormigón simple f`c= 180 kg/cm2. (Concrete mixing) m3. 1575,90 138,38 218073,04

Total 240730,98

These costs are in US dollars, in our outline of costs we use euros. The conversion factor: €/USD = 1/1,3155


Results experiment TU Delft

We did an experiment at the TU Delft. The results were not as good as we thought. There was a minimum decrease in leakage between self‐healing concrete and ordinary concrete. The experiment has not been performed accurately, because the self‐healing concrete had an healing time of 40 days, while after 70 days the difference between ordinary and self‐healing concrete is visible. The breaking of the disks has not been done accurately either. This experiment will be repeated to get accurate results.

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