Technical Report Draft 1

This proposal has been developed in response to the request for proposals on developing solutions to an engineering problem.

Water demand in Singapore uses approximately 430 million gallons a day. 45% of water usage is consumed by the domestic sector and the non-domestic sector takes up the rest. Singapore’s water supply is obtained from four water sources known as the Four National Taps. The Four National Taps consist of local water catchment, NEWater, desalinated water and Malaysia imported water. Local water catchment, NEWater and desalinated water contribute 40% of the water source, while Malaysia imported water contributes 60% of the water source. These water sources has helped with meeting the increase in water demand. According to Public Utilities Board (PUB) (2018), Singapore’s water demand is expected to double by 2060, with the non-domestic sector using about 70%. With the increase in demand of water usage, water prices are expected to increase gradually. Therefore, to keep up with the water demand in Singapore, planning and implementation of water saving strategy is required.

The geographical location of Singapore is located near the equator which results in higher precipitation. Based on figure 1, Singapore’s rainfall intensity is increasing over the years.

Figure 1: Annual Rainfall Total in Singapore (1980 - 2017)

As Singapore has high rainfall intensity, the practice of stormwater management is essential. Stormwater management is the control of surface runoff. As Singapore becomes more urbanised, there will be an exponential increase in surface runoff. Urban Redevelopment Authority states that the projected distribution by 2030, about 79% of the land in Singapore will be filled with infrastructure (Urban Redevelopment Authority, 2010).

Due to rapid urbanization in Singapore, more high rise buildings and infrastructure were being built which leads to the increase of surface runoff on rooftops. Therefore the implementation of rainwater harvesting on rooftop is regarded as a prefered method in Singapore context.

An ideal forward-looking campus should adopt implementation of rainwater harvesting on rooftop so as to be self sustainable and reduce dependency on external water sources. Nevertheless, rainwater harvesting has not been implemented in the new SIT@punggol. Without the implementation of rainwater harvesting, the reliance on using external water sources will increase the incurred cost of water. Having the SIT@Punggol campus planning committee adopt rainwater harvesting process, external water usage will be reduced and the campus would be self-sustained with the water supply.

The purpose of this report is to propose that the planning committee of SIT@Punggol campus to adopt rainwater harvesting on rooftop of the new campus to reduce the usage of water from external source so as to be self-sustainable.

Reader Response #Draft 3 #Final

This article, The Concrete Advantage, taken from Green Rooftops website, argues that hydrophobic concrete is a better choice for green rooftops as compared to membrane system concrete, which is high cost, unreliable, time wasting and ineffective.

According to the article, one of the tremendous disadvantages of having green rooftops is the membrane system concrete. Membrane system concrete increases the additional construction cost greatly and liability for the collaborators. With the elimination of membranes on the concrete, hydrophobic concrete makes designing, construction, and maintenance processes easier, faster and more manageable. The article also mentions that the perilous element will be eradicated by this hydrophobic technology while benefiting the stakeholders of the green roof. Hydrophobic concrete is durable, highly sustainable and able to detect any cracks and fix it without affecting neighboring plants and medium. 
The article also reports that hydrophobic concrete can remove the need of having the root barrier in green roof construction, where roots will not be able to absorb water from the concrete. However, no Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau (FLL) testing was done to justify and validate the content in the article. 

Overall, with the elimination of membranes on concrete, hydrophobic concrete has more advantages than membrane system concrete in terms of most aspects like time, cost, the life cycle of the concrete, and resources used. Therefore, hydrophobic concrete is a better option compared to membrane system concrete while reaping more benefits in the long run.

Firstly, concrete is one of the most sturdy and durable handmade material. However, when it hardens, the concrete will turn porous and eventually act as a hard sponge, absorbing fluid that seeps through the concrete surface, causing damage to the concrete 's chemical composition and steel reinforcement. To tackle this problem, a trusted company 'Hycrete' has come out a faster and cheaper solution which is to add special crystal admixtures into the standard concrete which react with the water and causes the crystal to grow and block the cracks. In the Article, WATERPROOFING ADMIXTURES FOR CONCRETE, states that  " crystalline products-proprietary active chemicals in a carrier of cement and sand. These are hydrophilic materials that increase the density of calcium silicate hydrate or generate crystalline deposits that block pores to resist water penetration." After the treatment the concrete will be hydrophobic, there it will be better than membrane system concrete.

Secondly, hydrophobic concrete helps to save cost and time.  From the statistic in the Hycrete website, Concrete That Fear Water No More, it states that the cost of membrane concrete and hydrophobic concrete is $6.00 per SF and $3..70 per SF respectively. The cost of hydrophobic concrete will be around 40% cheaper.  The article also mentions that " The approach virtually eliminated the need for waterproofing membrane on the foundation and slab portions of the project, saving up to two weeks of installation time and more than $150, 000 in membrane material cost." By looking at this statement and statistics from the trusted website, it proves that hydrophobic concrete saves a lot more cost and time compared to the membrane system. 

Thirdly, however, the admixture is used to enhance the concrete to increase its durability, workability, and strength, roots still may penetrate through the hydrophobic concrete over time causing water to seep in. Therefore, to repair and maintain the concrete, an injection can be done to the concrete to fix the cracks. For crystal admixture repair, the article states that " Unlike their hydrophobic counter-parts, crystalline systems actually use available water to grow crystal inside concrete. They block water from any direction because the concrete itself becomes the water barrier."  For normal admixture concrete, polyurethane is injected into the cracks and causing it to expand and block the pathway to prevent water from entering. The article also states that "non- flammable hydrophilic polyurethane resin designed to form a flexible gasket or plug joints and cracks in concrete." While membrane system requires to remove and reconstruct the concrete before repairing the cracks. Therefore, hydrophobic will be a better choice as it saves money and time to repair it.

With the above reasons and reliable sources, I can conclude that hydrophobic concrete has better benefits than membrane system concrete in terms of most aspects like time, cost, the life cycle of the concrete, and resources used. Therefore, hydrophobic concrete is a better option compared to membrane system concrete while reaping more benefits in the long run.

References

Green Rooftops. (n.d).  The Concrete Advantage. Retrieved from http://www.greenrooftops.org/advantage.html

Ken, H. (2012, August 13). WATERPROOFING ADMIXTURE FOR CONCRETE. Retrieved from https://www.concreteconstruction.net/how-to/materials/waterproofing-admixtures-for-concrete_o

Hycrete. (n.d). About Integral Waterproofing. Retrieved from https://hycrete.com/products/waterproofing/about-integral-waterproofing/

Barista D. (2007). Concrete That Fears Water No More.  Retrieved from http://hycrete.com/concrete-that-fears-water-no-more/

National Ready Mixed Concrete Association. (2001). Concrete in Practice.  Retrieved from https://www.nrmca.org/aboutconcrete/cips/15p.pdf

Building Trust Sika. (n.d). Waterproofing Injection. Retrieved from https://sgp.sika.com/en/solutions_products/02/02a007/02a007sa01.html

Smart Concrete. (2011, April 5). Understanding The Pros & Cons of Crystalline Waterproofing. Retrieved from https://www.kryton.com/in-the-news/2011/04/05/understanding-the-pros-cons-of-crystalline-waterproofing/

Reader Response #Draft 2

This article, The Concrete Advantage, taken from Green Rooftops website, argues that hydrophobic concrete is a better choice for green rooftops as compared to membrane system concrete, which is high cost, unreliable, time wasting and ineffective.

According to the article, one of the tremendous disadvantages of having green rooftops is the membrane system concrete. Membrane system concrete increases the additional construction cost greatly and liability for the collaborators. With the elimination of membranes on the concrete, hydrophobic concrete makes design, construction and maintenance processes easier and more manageable. The perilous element is eradicated by this hydrophobic technology while benefiting the stakeholders of the green roof. Hydrophobic concrete is durable, highly sustainable and able to detect any cracks and fix it without affecting neighboring plants and medium. Therefore, hydrophobic concrete is a better option while reaping more benefits in the long run.

With the elimination of membranes on concrete, hydrophobic concrete now has advantages in terms of most aspects like time, cost, the life cycle of the concrete, and resources used.  Another not proven benefit of having hydrophobic concrete is the elimination of root barrier in green roof construction where roots will not be able to absorb water from the concrete.  However, Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau (FLL) testing should be done to justify whether a root barrier can be eliminated as stated in the website, all green roof systems/ designs are compulsory to fulfill and meet the FLL guidelines and requirement, therefore this article is inaccurate.

The only improvement Green Rooftops shall improve is by doing a Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau (FLL) test. FLL should have done by Green Rooftops before publishing the article on the website. In the article, Green rooftops mention that "Thus far, there had been no FLL testing done to substantiate whether a root barrier can be eliminated. Roots do not seek water within the concrete because there is none in the waterproof concrete system."  However, based on the Green Roof Technology website, it states that "all green roof systems and green roof design must meet the FLL-Guideline and must last as long as the building where implemented." In my opinion, I strongly believe that the article shall be invalid and contain false information unless Green Rooftops have done and passed the FLL test before publishing the article on the website. Green Rooftops should also meet the requirements for root resistance of the waterproofing membranes. Green Rooftops should have done their FLL test at Center for Innovation and Technology Transfer (CRITT) Horticole and the Scientific and Technical Center for Building, European notified body for construction products (CSTB), CRITT horticole has greenhouses equipment to test the resistance to the root penetration of root protection membrane, roof and waterproof lining sheets and liquid surface treatment material according to the European standard EN 13948 and the FLL guidelines for the planning, construction and maintenance of green roofing. Without the root resistance testing evidence, I am unconvinced that the root barrier can be eliminated. When the plants are growing, there may be a chance that roots will grow towards the concrete causing it to crack and damage. After the concrete is cracked, there is a chance that water can sip in and trap the water causing damage to the concrete over time. With the above improvement, I believe that Green Rooftops will be a much more convincing website with test results and match requirement.


References

(2018). Epa.gov. Retrieved 30 September 2018, from https://www.epa.gov/sites/production/files/documents/IntroductiontotheGermanFLL2.pdf

Root resistance test EN 13948 - FLL - Critt Horticole. (2018). Critt Horticole. Retrieved 30 September 2018, from http://www.critt-horticole.com/activite/root-resistance-test-en-13948-fll/

Green Roof Systems | Green Roofing Solutions | Products, Materials. (2018). Greenrooftechnology.com. Retrieved 30 September 2018, from http://www.greenrooftechnology.com/greenroof-system

FLL Green Roof Guideline | German FLL Guideline | Green Roof Standard. (2018). Greenrooftechnology.com. Retrieved 30 September 2018, from http://www.greenrooftechnology.com/fll-green-roof-guideline

(2018). Ec.europa.eu. Retrieved 30 September 2018, from http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.showFile&rep=file&fil=GRO_Green_Roof_Code.pdf

Reader Response #Draft 1 

In this article, The Concrete Advantage, taken from Green Rooftops website argues, that concrete that undergone hydrophobic technology process will be a better choice for green rooftops as compared to membrane system concrete. This article also mentions the features of the hydrophobic concrete and stating how and why it can benefit the users. Although there are many advantages of having green rooftops on the building, there are some disadvantages too. One of the tremendous disadvantages of having green rooftops is the membrane system concrete. Membrane system concrete increases the additional construction cost greatly and liability for the collaborators. By using hydrophobic technology concrete by removing the membranes, it makes the design, construction, and maintenance processes easier and more effective, thus by eradicating the membranes, it also gets rid the most dangerous factor for the stakeholders. 

The five features of the hydrophobic concrete reported on the website are stated in the following below.

Firstly is the permanent "built-in" waterproofing, it is long lasting and does not need to worry about concrete from getting damage throughout the entire building and servicing phase.

Secondly is the elimination for the design and detailing of membranes, time used for designing, constructing phase and cost of the concrete green roofs project can be reduced greatly. 

Thirdly is the construction savings, when the membranes are removed, "water-proofing" sub

-contract works can be removed too.

Fourly is the lowering of square-foot cost, hydrophobic concrete is durable, long lasting thus it has higher sustainability rate and lower life cost cycle.

Lastly is that cracks can be quickly repaired with a simple injection from the underside of the green roof deck without affecting its neighbor growing medium or plants. While for the typical membrane system, it can be difficult to trace and expensive to repair.

Overall all these features have the similar benefits which as saving cost, resources and time. Another not proven benefit of having hydrophobic concrete is that it eliminates the use of root barrier in green roof construction where roots will not absorb water in the concrete. Based on the points and features elaborated, although Green Rooftops has stated that the concrete more sustainable, reliable and more efficient, Green Rooftops should have undergone the FLL test before publishing this article to make it valid and more convincing.

The only improvement Green Rooftops shall make is by doing a test, a Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau (FLL) test should have done by Green Rooftops before publishing the article on the website. In the article, Green rooftops mention that "Thus far, there had been no FLL testing done to substantiate whether a root barrier can be eliminated. Roots do not seek water within the concrete because there is none in the waterproof concrete system."  However, based on the Green Roof Technology website, it states that "all green roof systems and green roof design must meet the FLL-Guideline and must last as long as the building where implemented. "In my opinion, I strongly believe that the article shall be invalid and contain false information unless Green Rooftops have done and passed the FLL test before publishing the article on the website. Green Rooftops should also meet the requirements for root resistance of the waterproofing membranes. Green Rooftops should have done their FLL test at Center for Innovation and Technology Transfer (CRITT) Horticole and the Scientific and Technical Center for Building, European notified body for construction products (CSTB), CRITT horticole has greenhouses equipment to test the resistance to the root penetration of root protection membrane, roof and waterproof lining sheets and liquid surface treatment material according to the European standard EN 13948 and the FLL guidelines for the planning, construction and maintenance of green roofing. Without the root resistance testing evidence, I am unconvinced that the root barrier can be eliminated. When the plants are growing, there may be a chance that roots will grow towards the concrete causing it to crack and damage. After the concrete is cracked, there is a chance that water can sip in and trap the water causing damage to the concrete over time. With the above improvement, I believe that Green Rooftops will be a much more convincing website with test results and match requirement.


References

(2018). Epa.gov. Retrieved 30 September 2018, from https://www.epa.gov/sites/production/files/documents/IntroductiontotheGermanFLL2.pdf

Root resistance test EN 13948 - FLL - Critt Horticole. (2018). Critt Horticole. Retrieved 30 September 2018, from http://www.critt-horticole.com/activite/root-resistance-test-en-13948-fll/

Green Roof Systems | Green Roofing Solutions | Products, Materials. (2018). Greenrooftechnology.com. Retrieved 30 September 2018, from http://www.greenrooftechnology.com/greenroof-system

FLL Green Roof Guideline | German FLL Guideline | Green Roof Standard. (2018). Greenrooftechnology.com. Retrieved 30 September 2018, from http://www.greenrooftechnology.com/fll-green-roof-guideline

(2018). Ec.europa.eu. Retrieved 30 September 2018, from http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.showFile&rep=file&fil=GRO_Green_Roof_Code.pdf