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Effect of Addition of Shrinkage Reducing Admixture on Properties of Cement Mortar(PDF)

《建筑科学与工程学报》[ISSN:1673-2049/CN:61-1442/TU]

Issue:
2012年03期
Page:
55-60
Research Field:
Publishing date:

Info

Title:
Effect of Addition of Shrinkage Reducing Admixture on Properties of Cement Mortar
Author(s):
REN Hui-tao;  GUO Lei
Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China
Keywords:
shrinkage reducing admixture;  surface tension;  cement mortar;  shrinkage;  compressive strength;  flexural strength
PACS:
TU528.042
DOI:
-
Abstract:
The effect of mixing with shrinkage reducing admixtures(SRA)only and compounding with superplasticizer(SP)on shrinkage, compressive strength and flexural strength of mortar were comparatively investigated. The microstructure of the cement was determined by scanning electron microscopy(SEM), and the effects of SRA on the microstructure of cement hydration production products were studied. Results show that SRA can obviously reduce the shrinkage of mortar. The addition of SRA results in a reduction in shrinkage of 50% and 35%(compounding with SP)at 28 d, as compared to the control mixture. The shrinkage reducing effect of SRA is particularly evident at early age. Mortar containing SRA have indicated an expansion at early age, it's about 20% of total shrinkage, and these expansion effectively compensate the specimen shrinkage. SRA has a certain negative effect on the compressive strength and flexural strength of mortar. Compounding with SRA and SP can reduce the negative effect within 10%. SRA retards hydration of cement pastes and has physical and chemical effects in cement paste. SRA has physical effects to reduce the surface tension of pore solution, also has chemical effects of the hydration of cement to affect cement hydration products and mechanical properties of cement pastes.

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Last Update: 2012-09-20