Influence of molecular weight of long side-chain of polycarboxylic acid type water-reducer on early-age cracking behaviour of mortars

Title: Influence of molecular weight of long side-chain of polycarboxylic acid type water-reducer on early-age cracking behaviour of mortars
Author(s): B. Ma, H. Tan, L. Li, M. Zhang
Paper category : conference
Book title: International Conference on Microstructure Related Durability of Cementitious Composites
Editor(s): W. Sun, K. van Breugel, C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-065-3
e-ISBN: 978-2-35158-084-4
Publisher: RILEM Publications
Publication year: 2008
Pages: 953 - 958
Total Pages: 6
Nb references: 10
Language: English

Abstract: Several polycarboxylic acid type water-reducing agents (KHs) with different molecular weight of the long side-chain were synthesized. Effect of KHs on the setting time, chemical shrinkage, strength and initial cracking time of the cement-based material has been researched.
The results show that retarding effect on the setting time weakens, inhibition on hydration of cement mineral reduces, the chemical shrinkage increases and the strength development accelerates with the increasing of molecular weight of the long side-chain of KHs. Comparing with molecular weight of the long side-chain of 2000, the KH with the 400 molecular weight of the long side-chain can prolong initial setting time by 1.5 h and the final setting time by 2-3 h, reduce the 12 h chemical shrinkage of 50%, and prolong the initial cracking time by 35 h.
Adjusting the molecular weight of the long side-chain can reduce the cracking sensitivity of cement-based material. With increasing the molecular weight of the long side-chain of the KH, the cracking sensitivity increases and the maximum crack width becomes wider.

Online publication: 2009-06-09
Publication type : full_text
Public price (Euros): 0.00