Granolithic screed, also known as granolithic paving[1] and granolithic concrete,[2] is a type of construction material composed of cement and fine aggregate such as granite or other hard-wearing rock.[3] It is generally used as flooring, or as paving (such as for sidewalks). It has a similar appearance to concrete, and is used to provide a durable surface where texture and appearance are usually not important (such as outdoor pathways or factory floors).[3] It is commonly laid as a screed. Screeds are a type of flooring laid on top of the structural element (like reinforced concrete) to provide a level surface on which the "wearing flooring" (the flooring which people see and walk on) is laid.[4] A screed can also be laid bare, as it provides a long-lasting surface.[4]
The aggregate mixed with the cement can be of various size, shape, and material, depending on the texture of the surface needed and how long-lasting it must be.[5] The aggregate is usually sifted so that the particles are roughly the same size, which helps reduce air pockets in the material (which can weaken it).[1] Generally, the mix of aggregate to cement is 2.5 to 1 by volume.[1]
Granolithic screed or paving can be problematic. Because it is made with a high cement content and requires a great deal of water to mix, it may crack while drying.[3] It can also come loose from the material below (especially if the lower material is not properly prepared).[3] Pouring the material in layers is generally avoided.[6] Cracking and curling can be reduced by dividing the area to be covered into smaller sections and then pouring the material.[5] Debonding of the granolithic material can also be significantly avoided by using bonding agents like epoxy resins or polymer latex.
A high degree of skill in pouring and finishing the material is needed to prevent problems.[5] Sealers and hardeners can be added to the granolithic material to improve its resistance to wear.[1]
See also
edit- roughcast (pebbledash): visually somewhat similar, but used mostly on outer walls
Footnotes
editBibliography
edit- Emmitt, Stephen and Gorse, Christopher A. Barry's Introduction to Construction of Buildings. Chichester, U.K.: Wiley-Blackwell, 2010.
- Harris, Cyril M. Dictionary of Architecture and Construction. New York: McGraw-Hill, 2005.
- Ingham, Jeremy P. Geomaterials Under the Microscope: A Colour Guide. London: Manson, 2011.
- Ransom, W.H. Building Failures: Diagnosis and Avoidance. Florence, Ky.:Taylor & Francis, 1987.
- Snow, Dennis. Plant Engineer's Reference Book. 2d ed. Oxford: Butterworth-Heinemann, 2002.
- O'Brien, Chris "Joseet, Rueben" 2014.