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Investigation of effects of Portland cement fineness and alkali content on concrete plastic shrinkage cracking

Yang, Kai, Zhong, Mingquan, Magee, Bryan, Yang, Changhui, Wang, Chong, Zhu, Xiaohong and Zhang, Zhilu (2017) Investigation of effects of Portland cement fineness and alkali content on concrete plastic shrinkage cracking. Construction and Building Materials, 144 (30). pp. 279-290. [Journal article]

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DOI: 10.1016/j.conbuildmat.2017.03.130

Abstract

From a material viewpoint, modern concrete’s frequent propensity to plastic shrinkage cracking can be attributable to a combination of low water-binder ratio use and ever-changing properties of binding materials. To obtain a better understanding of this phenomenon, this paper explores the effects of cement fineness and alkali content on the plastic shrinkage cracking of concrete manufactured with two water-binder ratios. Results indicate that within the range 275–385 m2/kg, cement specific surface area is approximately directly and inversely proportional to hydration rate and evaporation rate respectively; a trend generally leading to higher plastic shrinkage and resulting areas of plastic cracking. Similar effects were observed for alkali contents which resulted in increased levels of plastic shrinkage. Furthermore, while decreasing crack tendency was noted as alkali content increased from 0.4 to 0.8% by mass of cement, further increases in alkali content caused significant decreases of compressive strength and slump; thereby lowering overall concrete performance. It is also found that plastic shrinkage cracking is closely related to the kinetics of plastic shrinkage. In summary, the experimental programme confirmed that cement with relatively low surface area (less than 340 m2/kg) and low alkali content (less than 0.8%) is preferred for modern concretes with minimal plastic cracking problems.

Item Type:Journal article
Keywords:Shrinkage; Concrete and cement; Concrete structures; Moisture loss
Faculties and Schools:Faculty of Art, Design and the Built Environment
Faculty of Art, Design and the Built Environment > School of the Built Environment
Research Institutes and Groups:Built Environment Research Institute
Built Environment Research Institute > Studies Allied to Built Environment Research (SABER)
ID Code:37468
Deposited By: Dr Bryan Magee
Deposited On:14 Apr 2017 08:37
Last Modified:03 Apr 2018 22:23

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