Assignment 2 - Summary Reader Response

According to the article, "Scientists create living concrete from bacteria and sand", researchers from the University of Colorado Boulder have created living concrete from bacteria and sand. They have introduced a new living material, by combining sand, hydrogel and bacteria.

The article explains that photosynthetic cyanobacterium was biomineralized with a 3D sand-hydrogel scaffold, which produces new bricks from the original brick. The article also claims that biological viability and mechanical performance cannot coincide. Thus, additives are incorporated to enhance the quality of the material. Hence, it possesses properties that are comparable to cement-based mortar, which carries biological purposes. Corless interviewed Srubar (2020), the director of Living Materials Laboratory, and he said that this process will change people's thinking about the manufacturing industry and reusable materials. Corless further mentions that despite this technology being in its early development phase, it represents a new era in material manufacturing: a new grade of responsive materials “in which structural function is complemented by biological functions.”

The prospects of replacement materials for cement are still being explored. Considering other alternatives, such as sugarcane bagasse ash, 3D concrete printing, and microsilica (silica fume) for partial cement replacement.

As mentioned above, studies are conducted to find alternative methods for cement production. In a research article from Mehran University of Engineering and Technology, researchers study the use of sugarcane bagasse ash to replace cement in the making of cement concrete. Since SCBE can partially replace the clinker in cement production, it reduces the emission of CO2 into the atmosphere. The emissions reduction according to UNFCCC was 519.3-kilo tons of CO2 per year. In addition to this, researchers from Malaysia also reviewed seashell ash as partial cement replacement. By utilizing the waste products to produce the ashes and replacing cement, it will possibly decrease the carbon emissions of cement production. These waste products are economical and helpful in producing a sustainable environment and reducing the environmental pollution. 

An article from the Swinburne University of Technology writes about the progress of 3D concrete printing (3DCP) technology. The article stated that although 3DCP is still an emerging technology, it is rapidly progressing in such a way that 3D printing of large-scale concrete structures may become a reality in near future. With abundant carbon emission when producing Ordinary Portland Cement (OPC), geopolymer is a sustainable alternative to OPC. Geopolymer has superior mechanical, chemical and thermal properties and 80% lesser carbon emissions as compared to OPC. The article concludes that future works will focus on enhancing the properties of 3D printed geopolymer structures. 

The use of silica fumes as partial cement replacement can decrease air pollution. A research article states researchers of Arni University, India (2016) studied the use of silica fumes replacing 0% to 15% of cement. “The strength of concrete increases rapidly as we increases the silica fume content and the optimum value of compressive strength is obtained at 10% replacement.”  The results showed that partial replacement of cement with silica fumes had a significant effect on the compressive strength of the cube. This proves that SF can replace cement.

In conclusion, there are innovative researchers attempting to find alternative methods of cement production and these are just a few. Methods like the cyanobacteria have pushed beyond the structural boundaries of construction and even 3D concrete printing may not attain the qualities of traditional concrete. Nevertheless, it should not stop the never-ending search for new possibilities for alternative concrete production or substitute materials. 

References:

Corless, V. (2020). Scientists create living concrete from bacteria and sand. Retrieved 30 January 2022, from https://www.advancedsciencenews.com/scientists-create-living-concrete-from-bacteria-and-sand/ 

Use of Sugarcane Bagasse Ash as Cement Replacement Materials in Concrete. (2019). [Ebook]. Pakistan. Retrieved from http://icsdc.muet.edu.pk/wp-content/uploads/2020/05/12.pdf 

Current Progress of 3D Concrete Printing Technologies. (2017). [Ebook] (pp. 260-267). Melbourne, Australia. Retrieved from https://www.researchgate.net/profile/Behzad-Nematollahi/publication/318472250_Current_Progress_of_3D_Concrete_Printing_Technologies/links/5ec7d2df299bf1c09ad30508/Current-Progress-of-3D-Concrete-Printing-Technologies.pdf