Influence of spraying on the early hydration of accelerated cement pastes

Journal Article · Sat Oct 15 04:00:00 EDT 2016 · Cement and Concrete Research

DOI:https://doi.org/10.1016/J.CEMCONRES.2016.06.005· OSTI ID:22697073

Cano, Miguel ^[1]; Figueiredo, Antonio D. ^[2]

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1. Industrias Químicas del Ebro, Poligono de Malpica, D 97, 50016 Zaragoza (Spain)
2. Department of Civil Construction Engineering, Polytechnic School of University of São Paulo, USP, Professor Almeida Prado, Trav 2, 83, 05424-970 São Paulo (Brazil)

In practice, most of the studies about the interaction between cement and accelerators is performed with hand-mixed pastes. However, in many applications mixing occurs through spraying, which may affect accelerators reactivity and the microstructure of the hardened paste. The objective of this study is to analyze how the mixing process influences the early hydration of accelerated cement pastes. Isothermal calorimetry, X-ray diffraction, thermogravimetry and SEM imaging were performed on cement pastes produced by hand-mixing and by spraying, using equivalent doses of an alkali-free and an alkaline accelerator and two types of cement. Results showed a great influence of the spraying process on the reactivity of accelerators and on the morphology of the precipitated hydrates. Variations in hydration kinetics caused by the mixing method are explained and the results obtained might have a significant repercussion on how future research on the behavior of accelerated mixes will be performed.

• OSTI ID: 22697073
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Vol. 88; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACCELERATORS
BIOMEDICAL RADIOGRAPHY
CEMENTS
HYDRATES
HYDRATION
MIXING
PRECIPITATION
SCANNING ELECTRON MICROSCOPY
THERMAL GRAVIMETRIC ANALYSIS
X RADIATION
X-RAY DIFFRACTION