Long-term properties of cement mortar under compression, tension, and 3-point bending

• Main Authors: Sprince Andina, Gailitis Rihards, Pakrastins Leonids, Kozlovskis Tomass, Vatin Nikolai
• Format: Article
• Language: English
• Published: Peter the Great St. Petersburg Polytechnic University 2021-09-01
• Series: Magazine of Civil Engineering
• Subjects: long-term properties; creep; shrinkage; compression; tension; 3-point bending; digital image correlation; pva fibre; opc mortar
• Online Access: http://engstroy.spbstu.ru/article/2021.105.11/

Cement composite long-term property assessment usually is limited to the compression strain state due to the difficulty of performing long-term tests in tension and 3-point bending. This paper shows the difference in long-term properties in compression, tension, and 3-point bending for plain ordinary Portland cement mortar (OPC). The obtained results were compared to reinforced specimen results to determine whether the PVA refibres improve the long-term properties of OPC mortar in various stress-strain conditions. Cylinders, compact tension specimens (CT), and beams – plates were prepared to evaluate material properties and the role of fibre reinforcement in these different stress states. Additionally, to conventional surface-attached strain gauges, 2D-DIC was employed to observe the creep strain of specimens in tension. This paper aim to determine long-term property differences in compression, tension and 3-point bending and, also, to see if low amount PVA fibre incorporation improve long-term properties in previously stated stress-strain states. It was determined that the usage of 1 % of PVA fibres increases creep strains in compression on average by 15 % and reduced by 7 % in tension. It reduces shrinkage strain by 18 % in compression and 8 % in tension. The long-term deflection for the PVA fibre-reinforced specimens are, on average by 55 % higher than for plain OPC mortar specimens in 3-point bending.