The article “The Concrete Advantage” taken from the Green Rooftop website provides readers the advantages and disadvantages of concrete green roof. According to the article, the process of design, construction and maintenance will be shortened in projects using waterproof concrete as membranes are not required for the development. This in turn leads to higher work efficiency and reduces the overall cost of the project. On the other hand, the main downfall of projects involving the use of waterproof concrete would be additional construction cost.
The article mentions that the waterproof concrete contains permanent ""built in"" waterproofing elements that cannot be damaged or torn during service. This will improve project feasibility as regular maintenance are not required. Cracks can also be repaired quickly with a simple inoculation from the bottom side of the green roof deck, which does not disrupt growing medium or plants. With fewer exposure risk for owners and designers, such green roofs are more economical which boosts returns on investment and project value. In addition, this hydrophobic technology removes dangerous element for the designer and owner of a green roof, increases financial viability, and enhances owner acceptance. While I agreed that this article may be true, the lack of an analysis on the disadvantages of waterproof concrete and the different types of waterproof concrete admixtures makes the article less reliable and incomplete.
The first reason is because the article did not discuss the disadvantages of waterproof concrete. According to “The Concrete Advantage (2016), there is not a single admixture that offers 100% waterproofing. In addition, although this admixture may produce many positive results, it may still not be able to outperform under certain circumstances. For example, this product is not applicable to areas subjected to bending movement and vibrations as the materials used are not flexible (Cementitious Waterproofing, 1996). Research studies have also discovered that concrete produced with hydrophobic chemical admixtures could theoretically resist some hydrostatic pressure. However, as not all pores are uniformly coated with the waterproof material, such concrete is not classified as permeability-reducing admixture exposed to hydrostatic conditions (Hooker, 2012). Therefore, waterproof concrete has its disadvantages depending on its application and type.
This article is also incomplete as it did not mention the details on the different types of concrete waterproof admixtures. The benefits highlighted in this article could mainly be referring to a particular waterproof system. Research studies have shown that integral concrete hydrophobic systems generally consist of three kinds of admixtures, namely: densifiers, water repellents and crystalline (Yuers, 2011). Although these three waterproof materials might have the same functions, they each have their own limitations. By comparing all three, the article would leave the readers a better understanding of their characteristics respectively.
In conclusion, while this article provides the main advantages of waterproof concrete, it lacks of an analysis of the limitations and description of the system. It is important to know a product in detail so as to evaluate its efficiency and to allow for improvements. Generally, this system has more benefits than disadvantages. Hence, it is widely used worldwide.
References:
The Concrete Advantage. Retrieved September 20, 2016, from http://www.greenrooftops.org/advantage.html
Yuers.K. (2011). Understanding The Pros & Cons of Crystalline Waterproofing Retrieved September 22, 2016, from http://www.kryton.com/in-the-news/2011/04/05/understanding-the-pros-cons-of-crystalline-waterproofing/
Hooker.K. (2012). Waterproofing admixtures for concrete. Retrieved September 25, 2016, from http://www.kryton.com/in-the-news/2011/04/05/understanding-the-pros-cons-of-crystalline-waterproofing/
Cementitious Waterproofing. (1996). Retrieved September 25, 2016, from http://www.csibaltimore.org/index_files/Cementitious%20Waterproofing%20-%20Mar%201996.pdf
