Probabilistic functions of mechanical properties of plain cement pastes determined by a reduced-size test

Author(s)

Oliveira, Fabio C. ^[1] ; Kassab, Marcos P. ^[1] ; Silva, V, Natalia ; Angulo, Sergio C. ^[2] ; Tavares, Luis Marcelo ^[3] ; Lange, David A. ^[4]

Affiliation

^[1] Univ Sao Paulo, Escola Politecn, Sao Paulo, SP - Brazil

^[2] Silva, Natalia, V, Univ Sao Paulo, Escola Politecn, Sao Paulo, SP - Brazil

^[3] Univ Fed Rio de Janeiro, Dept Met & Mat Engn, Rio De Janeiro, RJ - Brazil

^[4] Univ Illinois, Civil & Environm Engn, Champaign, IL - USA

• Document type: Journal article
• Source: CONSTRUCTION AND BUILDING MATERIALS; v. 286, JUN 7 2021.
• Web of Science Citations: 0

Abstract

Knowledge of the mechanical properties of plain cement pastes, as well as their variability, is important to predict the properties of concretes. Pastes are very susceptible to critical defects that not only reduce the mechanical strength but also increase the variability. The paper proposes a method to evaluate the tensile strength and the elastic modulus of cement pastes, based on the Point Load Test and the Hertz Contact Theory, from experiments on reduced-size cubic samples (similar to 10 mm). Three cement pastes with w/c ratios of 0.30, 0.50 and 0.70 were produced and 40 samples were cast for each paste. A simple method of estimating the chemically combined water and the effective w/c ratio (after bleeding in the stationary stage) of each sample was proposed. Being an expedite method, it allowed obtaining more than 100 valid mechanical results in about 8 h of testing using less than 250 g of cement, with values of tensile strength and elastic modulus that approached the macroscale reference values from the literature. The tensile strength of cement pastes varied considerably, but in the range informed in the literature, whereas the elastic modulus was less variable. Probabilistic functions for the characteristic values of the mechanical properties were provided. (C) 2021 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 16/20420-2 - Strenght of aggregates: control and effect on mechanical behaviour of concretes
• Grantee: Sérgio Cirelli Angulo
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/07623-7 - Mechanical properties of cement pastes: microstructure, variability and probabilistic analysis
• Grantee: Fábio Cabral de Oliveira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 18/07423-8 - Mechanical properties of cementitious pastes: probabilistic analyses
• Grantee: Marcos Pires Kassab
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 14/50948-3 - INCT 2014: advanced eco-efficient technologies in cementitious products
• Grantee: Vanderley Moacyr John
• Support Opportunities: Research Projects - Thematic Grants