Effect of main and side chain length change of polycarboxylate‐ether‐based water‐reducing admixtures on the fresh state and mechanical properties of cementitious systems


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Özen S., Altun M. G. , Mardanı Aghabaglou A., Ramyar K.

Structural Concrete, vol.22, pp.607-618, 2021 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 22
  • Publication Date: 2021
  • Journal Name: Structural Concrete
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.607-618
  • Bursa Uludag University Affiliated: Yes

Abstract

In this study, the effect of both main and side chain length changes of the

admixtures on some properties of cementitious systems were investigated.

Three different polycarboxylate-ether-based water-reducing admixtures (WRA)

having constant molecular weights and different main and side chain lengths

were synthesized. Single type of raw material and carboxylate functional group

were used in all WRAs. The molecular weights, free nonionic contents, and

anionic/nonionic ratios of the admixtures were kept constant. Test results

showed that degree of fluidity was observed in cement paste and mortar mixtures

in case the admixture main and side chain length is more or less than a

critical value. This negative effect is thought to be due to the weakening of the

adsorption ability by the chain length change of the admixtures, the being tendency

of polymers to intertwine and the adsorbing of admixture on several

cement particles simultaneous. Admixtures having excessive long or short

main chain and side chain improved the time-dependent slump-flow retention

of the mortar mixtures. The admixtures with short main and side chains had

insufficient adsorption ability and the admixture with excessive long main and

side chains had the interlacing risk of polymers. In both cases, time-dependent

behavior improved because the amount of free admixture in solution

increased. The change in the chain lengths of the WRAs affected the 1-day

compressive strength of the mortar mixtures.