An Influence of Interfacial Transition Zone on Local and Overall Fracture Response of Cementitious Composites

An Influence of Interfacial Transition Zone on Local and Overall Fracture Response of Cementitious Composites

Abstrakt

In this paper, the fracture properties of ITZ of fine-grained cement based composite with different types of rock inclusion – basalt, granite, marble and amphibolite – were studied. Specimens with the initial stress concentrator were tested in standard three-point bending configuration and overall macroscopic fracture response was assessed. Nominal dimensions of test specimens were 40 × 40 × 160 mm, the notch depth was approximately 1/3 of specimen depth. Rock inclusions were placed above the initial notch (in the middle of specimen depth) and dimensions of rock inclusions were 8 × 8 × 40 mm. After the fracture tests had been performed, microstructure of fracture surfaces were studied by means of light and electron microscopes. Local ITZ response was characterized by nanoindentation technique in the vicinity of rock inclusions. Local elastic modulus, hardness and viscous properties of ITZ were assessed. It has been shown the ITZ is mechanically weaker compared to the bulk matrix in the region of ca. 0–20 μm from the inclusion surface for all inclusion types. It exhibits gradual increase of elastic modulus and hardness, which can be approximately expressed by a power law. On the other hand, the creep in ITZ was found to be higher compared to the bulk matrix.

In this paper, the fracture properties of ITZ of fine-grained cement based composite with different types of rock inclusion – basalt, granite, marble and amphibolite – were studied. Specimens with the initial stress concentrator were tested in standard three-point bending configuration and overall macroscopic fracture response was assessed. Nominal dimensions of test specimens were 40 × 40 × 160 mm, the notch depth was approximately 1/3 of specimen depth. Rock inclusions were placed above the initial notch (in the middle of specimen depth) and dimensions of rock inclusions were 8 × 8 × 40 mm. After the fracture tests had been performed, microstructure of fracture surfaces were studied by means of light and electron microscopes. Local ITZ response was characterized by nanoindentation technique in the vicinity of rock inclusions. Local elastic modulus, hardness and viscous properties of ITZ were assessed. It has been shown the ITZ is mechanically weaker compared to the bulk matrix in the region of ca. 0–20 μm from the inclusion surface for all inclusion types. It exhibits gradual increase of elastic modulus and hardness, which can be approximately expressed by a power law. On the other hand, the creep in ITZ was found to be higher compared to the bulk matrix.

fine-grained cement-based composite, rock inclusion, interfacial transition zone, nanoindentation, microstructure

fine-grained cement-based composite, rock inclusion, interfacial transition zone, nanoindentation, microstructure

ZACHARDA, V.; NĚMEČEK, J.; ŠIMONOVÁ, H.; KUCHARCZYKOVÁ, B.; VYHLÍDAL, M.; KERŠNER, Z.

2018

06.11.2017

Institute of Materials Research of SAS

Košice

Book of abstracts 13th Conference on Local Mechanical Properties

26

27

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