The Evaluation of the Addition of Phosphatic Clay in Cement Paste and Concrete
2011 (English)In: International Journal of Materials Engineering and Technology, Vol. 5, no 2, 101-114 p.Article in journal (Refereed) Published
Phosphatic clay is a by-product of the phosphate strip mining industry, and disposal is particularly a problem in Florida, USA. This waste material occupies about 100,000 acres of land which could be utilized for other causes. Thus, its potential utilization as a supplementary cementing material added to the cement paste matrix of concrete to produce higher strength would be beneficial for both the mining and construction industries. The waste clay contains calcium montmorillonite, which should react pozzolanically with the calcium hydroxide produced from the hydration reactions to produce additional C-S-H, the building block of concrete systems, and thus enhancing the mechanical properties of cement paste and concrete. The effects of phosphatic clay addition on the bulk properties of cement paste and concrete are investigated, and it is shown that moderate additions (5% replacement of cement by mass) can indeed produce a significant increase in strength. The effect of the modified paste on the interfacial transition zone in concrete is also observed.
Place, publisher, year, edition, pages
2011. Vol. 5, no 2, 101-114 p.
phosphatic clay, waste material in concrete, modification of concrete, interfacial transition zone
IdentifiersURN: urn:nbn:se:kth:diva-84098OAI: oai:DiVA.org:kth-84098DiVA: diva2:499165
TSC import 1938 2012-02-10. QC 201204112012-02-132012-02-132012-04-11Bibliographically approved