Segregation in concrete

It is described by American Society for Testing and Materials as follows: "Segregation in concrete is commonly thought of as separation of some size groups of aggregates from cement mortar{{#tag:ref|Mortar is a mixture of fine aggregates and cement, that in concrete acts as a binder between particles of coarse aggregates.{{cite book|author=Ttti Chandigarh|title=Civil Engineering Materials|url=https://books.google.com/books?id=ruT2eiL8o-MC&pg=PA118|access-date=20 May 2012|date=1 July 2001|publisher=Tata McGraw-Hill Education|isbn=978-0-07-460431-1}}{{rp|119,120}}|group="nb"}} in isolated locations with corresponding deficiencies of these materials in other locations. Segregation results in proportions of the laid concrete being in variation with those designed.{{cite book|author=American Society for Testing Materials. Committee C-9 on Concrete and Concrete Aggregates|title=Significance of Tests and Properties of Concrete and Concrete Aggregates: A Résumé of Present Information on the Significance of the Properties of Concrete and Concrete Aggregates and the Tests by which They are Studied and Determined|url=https://books.google.com/books?id=plRnBOM30TEC&pg=PA38|access-date=20 May 2012|date=1 January 1956|publisher=ASTM International|id=GGKEY:SL4DFHZUPJ6}}{{rp|38}} Segregation could result from internal factors such as concrete that is not proportioned properly and not mixed adequately, or too workable a mix. It also could result from external factors such as too much vibration,{{#tag:ref|Compaction describes the process employed to obtain maximum density in concrete after it has been deposited in place. Compaction could be achieved by mechanical vibrators, devices that vibrate at various frequencies and which transfer these vibrations to concrete.{{rp|144}}|group="nb"}} improper transportation, placement, or adverse weather conditions.{{cite book|author1=Sybil K. Reinert|author2=Iowa State University. Civil, Construction, and Environmental Engineering|title=Optimizing Portland Cement Concrete Mix Design to Environmental and Construction Variables with the Aid of Computer Design Software|url=https://books.google.com/books?id=hVwb4wOCN0kC&pg=PA7|access-date=20 May 2012|year=2007|isbn=978-0-549-33432-3}}{{rp|7,8}} The corresponding increase in proportion of cement paste in upper areas would tend to make them susceptible to increased shrinkage and formation of cracks. These cracks could be 10 μm to 500 μm wide, formed perpendicular to the surface, and be in the form of map patterns."{{cite book|author1=Ravindra K. Dhir|author2=Mukesh C. Limbachiya|title=Utilizing Ready Mix Concrete and Mortar: Proceedings of the International Conference Held at the University of Dundee, Scotland, UK on 8-10 September 1999|url=https://books.google.com/books?id=nE6Yww-9wNIC&pg=PA148|access-date=20 May 2012|year=1999|publisher=Thomas Telford|isbn=978-0-7277-2823-4}}{{rp|149}}

The concrete should be free from segregation. It is defined as the breaking up of cohesion (separation of concrete aggregate) in a mass of concrete. It results in honey-combing, decrease in density, and ultimately loss of strength of hardened concrete. The effect of aggregate segregation on the mechanical and transport behavior of concrete has been the focus of both modeling as well as experimental investigation.

• Properties of concrete

{{reflist}}

• {{cite book | url=https://books.google.com/books?id=vU1tSqtMu6IC&q=concrete+segregation&pg=PA133 | title=The Contractor's Guide to Quality Concrete Construction | publisher=American Concrete Institute | date=2005 | page=133 | access-date=May 19, 2012 | author=American Society of Concrete Contractors| isbn=9780870311673 }} {{ISBN|0870311670}}
• [https://dx.doi.org/10.1016/j.compositesb.2015.06.024 Towards a realistic morphological model for the meso-scale mechanical and transport behavior of cementitious composites] Davood Niknezhad; Balaji Raghavan; Fabrice Bernard; Siham Kamali-Bernard; Composites Part A: Engineering, Volume 381, 72–83, 2015 Elsevier

• [https://www.civilexperiences.com/2021/08/concrete-segregation.html Segregation in concrete] - from Civil Experiences
• [http://freevideolectures.com/Course/86/Building-Materials-and-Construction/12 Lecture 12: Module 5 Lecture - 4 Fresh Concrete : Segregation & Bleeding]{{spaced ndash}} from the Indian Institute of Technology, Delhi

{{Concrete navbox}}

Category:Concrete

{{Civil-engineering-stub}}