CEMCON 2019: Conference on Modern Trends in Construction Technology & Concrete

CEMCON 2019, the two day conference on Modern Trends in Construction Technology and Concrete was organised at Pune (India), on 13-14 December 2019. 

Dr J D Bapat made a presentation on "Cement-Based Building materials". Four types of Cement-Based Building Materials were presented, namely Dry Mixed Mortar (DMM) Plaster, Cement-Based Fly Ash Bricks, Autoclaved Aerated Concrete (AAC) Blocks and Micro Concrete for Concrete Repair Work. 

The conference was attended by nearly delegates from construction industry. 12 experienced professionals from construction industry made their presentations. All presentations were followed by interesting q/a session, which saw very active participation. 

Visit Dr J D Bapat's website: Cement Manufacturing & Concrete

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A lesson for structural engineers

While researchers have long known of the incredible strength of spider silk, the robust nature of the tiny filaments cannot alone explain how webs survive multiple tears and winds that exceed hurricane strength.

Now, a study that combines experimental observations of spider webs with complex computer simulations shows that web durability depends not only on silk strength, but on how the overall web design compensates for damage and the response of individual strands to continuously varying stresses.

Engineered structures are typically designed to withstand large loads with limited damage, but extreme loads are more difficult to account for. The spider has uniquely solved this problem by allowing a sacrificial member to fail under high load. One of the first questions a structural engineer must ask is ‘What is the design load?' For a spider web, however, it doesn't matter if the load is just strong enough to cause failure, or one hundred times higher--the net effect is the same. Allowing a sacrificial member to fail removes the unpredictability of 'extreme' loads from the design equation."

For detailed information on NSF-supported research elsewhere in Massachusetts, see results for Massachusetts on Research.gov.

Ref: NSF Press Release 12-016:  A Spider Web's Strength Lies in More Than its Silk

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Self-cleaning Concrete: Applications

The Photocatalytic Cement is already being used for sound barriers, concrete paver blocks, façade elements. Other applications include:

* Precast and architectural concrete panels
* Pavements, road surfacing and sidewalks
* Portland cement-based plaster for finish coat applications
* Concrete masonry units, roof tiles and cement-based tiles
* Cement-based restoration products

The best applications, for cost effectiveness, include any product used in thin layers or produced in a two-stage manufacturing process (with structural and face mixtures).

In one of the more innovative applications, Italcementi has successfully partnered with lighting system makers to develop artificial lighting systems that generate enough ultraviolet light to activate the photocatalytic process. The lighting system and photocatalytic cement concrete have been used in the renovation of a heavily trafficked tunnel in Rome.

The Photocatalytic cement has already been used in North America. A white precast concrete carillon tower was constructed at Dalton State College in Georgia. The 23 m tall tower is the centerpiece of a new quadrangle project and is visible from a nearby freeway, so it is important that it remains pristine.
Hyacinth Place, an affordable “green” housing complex in Highland Park, IL, has courtyard areas with concrete pavers incorporating photocatalytic cement. The pavers help clean the air as well as store and filter storm water that would have normally been nuisance runoff. The photocatalytic cement was used to
produce two 9 m tall gateway elements at the entrances to the new I-35 W bridge in Minneapolis, MN. These gleaming white concrete sculptures represent the
international symbol for water and serve as markers to remind travelers they’re crossing the Mississippi River. With the help of advanced technology and energy from the sun, they will remain proud symbols for decades to come.

The rain washes away the pollution from the concrete surface, hence buildings stay cleaner and do not require chemical applications that are potentially harmful to the environment. Maintenance costs are reduced. This is true even for buildings in highly polluted locations. One noted application is the Air France headquarters at Roissy-Charles de Gaulle International Airport near Paris, a white concrete building that has remained white. Another is the Church of the Year 2000 in Rome.

Clean buildings are great. Perhaps even more astounding environmental benefit is the potential for cleaner air. Concrete products that are exposed to sunlight throughout their life, like precast building panels, pavers and roof tiles, are especially suited to manufacture with photocatalytic cement. For instance, city streets made with special pavers are capable of reducing the pollution at its source—where it comes out of the tailpipe.

Question:

Discuss techno-economic feasibility of using Photocatalytic Cement in a building project

Reference:

(1) Barbesta M. and Schaffer D, "Concrete that cleans itself and the air", Concrete international, February 2009, pp 49-51

Bacterial Concrete: Applications

Giancarlo Ranalli, an Italian researcher in Pesche, Italy, has already used bacteria to clean the base of Michelangelo's Pietà Rondanini in Milan and another kind of bacteria to remove harmful animal glue from frescos in Pisa. Ramirez also describes the use of forensic DNA techniques to identify burrowing insects in wooden pieces from just minuscule droppings or a tiny body part so that the precise species can be identified and properly eradicated, as well as the use of biomineralization process(same as that used in making the bacterial concrete) in which microbes, introduced to a crack in a stone sculpture, will deposit a calcium carbonate that picks up the color of the original while filling the gap.

"Science has finally set a solid foot in the art world," says José Luis Ramirez, co-author of a 2005 study of the use of biotechnology in art preservation and director of the United Nations University's Program for Biotechnology for Lain America and the Caribbean (BIOLAC), which is an interdisciplinary school that promotes the use of biotechnology in fields from agriculture to manufacturing.

Bibliography:

1. Bang, S.S., Galinat, J.K. & Ramakrishnan, V. Calcite precipitation induced by polyurethaneimmobilized Bacillus pasteurii, Enzyme and Microbial Technology 28 (2001) 404–409
2. Rodriguez-Navarro, C, Rodriguez-Gallego, M., Chekroun, K.B. and Gonzalez-Munoz, M.T. Conservation of Ornamental Stone by Myxococcus xanthus-Induced Carbonate Biomineralization, Applied and Environmental Microbiology, Apr. 2003, p. 2182–2193.
3. Ramikrishnan, V., Panchalan, R.K. and Bang, S.S. Improvement of concrete durability by bacterial mineral precipitation, in Proc. ICF 11, Torino, Italy, 2005.
4. Ramakrishnan V., Ramesh K. P., Bang S. S., “Bacterial concrete”, Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE), The International Society for Optical Engineering, Bellingham, WA, Vol. 4234, 2001, pp. 168-176
5. Stocks-Fischer, S., Galinat, J. K., and Bang, S.S., “Microbiological precipitation of CaCO3”, Soil Biology and Biochemistry, Vol. 31, 1999, pp. 1563-1571
6. Gollapudi, U.K., Knutson, C.L., Bang, S.S., and Islam, M.R., “A New method for Controlling Leaching through Permeable Channels”, Chemosphere, Vol. 30, No. 4, 1995, pp. 695-705
7. Zhong, L., And Islam, M.R., “A New Microbial Process and its Impact on Fracture Remediation”, 70th Annual Technical Conference and Exhibition of the Society of Petroleum Engineers, Dallas, Texas, Oct 22-25, 1995.
8. Harmon K.,"The Science of Saving Art: Can Microbes Protect Masterpieces?",
Scientific American, February 9, 2009

Question:

Discuss possible applications of bacterial concrete