Effect of coarse aggregate size and matrix quality on ITZ and failure behavior of concrete under uniaxial compression

2004-08-01
Akcaoglu, T
Tokyay, Mustafa
Celik, T
Effects of coarse aggregate size and water/cement (w/c) ratio of the matrix on the formation of interfacial transition zone (ITZ) and subsequently on the failure process of concrete under uniaxial compression were studied. For this purpose, a series of experiments were designed and carried out on mortars with two different w/c ratios containing single spherical steel aggregates of different sizes. The ITZ properties and the failure process of concrete were investigated through tensile strength tests both before and after compressive preloading, stress-axial strain, stress volumetric strain and stress-lateral strain measurements. It was observed that ITZ becomes critical for larger aggregates and lower w/c ratio mortar matrices. The negative effect of smooth surface texture of the aggregate and the large difference between aggregate and matrix moduli of elasticity on the properties of ITZ is of paramount importance for low w/c ratio composites. The effect of reduced bond properties of ITZ relative to its matrix was reflected in the lower critical stress levels for the low w/c ratio composites with larger aggregates.
CEMENT & CONCRETE COMPOSITES

Suggestions

Effect of coarse aggregate size on interfacial cracking under uniaxial compression
Akcaoglu, T; Tokyay, Mustafa; Celik, T (2002-12-01)
The effects of aggregate type and size are important parameters in the formation of interfacial transition zone (ITZ) structure and subsequently in the failure process of concrete. The influence of surface, rigidity and size of aggregates and water/cement (w/c) ratio of the matrix on bond strength at the ITZ and the interrelationship between the bond and the matrix in the failure process of concrete under uniaxial compression were studied. For this purpose a series of experiments were designed and carried o...
Assessing the ITZ microcracking via scanning electron microscope and its effect on the failure behavior of concrete
Akcaoglu, R; Tokyay, Mustafa; Celik, T (2005-02-01)
The influence of aggregate size and water-to-cement (w/c) ratio of the matrix on the structure of interfacial transition zone (ITZ) and the interaction between the ITZ and the matrix on the failure process of concrete under uniaxial compression were studied. The ITZ microcracking and the failure process of concrete were investigated experimentally by means of compressive and indirect tensile testing, stress-volumetric strain measurements and microscopic analyses on the model concrete containing single spher...
Effect of thermal induced flexural strain cycles on the low cycle fatigue performance of integral bridge steel H-piles
Karalar, Memduh; Dicleli, Murat (2016-10-01)
Close examination of the field measurement data for integral bridges revealed that the measured cyclic flexural strains in steel H-piles at the abutments due to thermal fluctuations consist of large amplitude, primary small amplitude and secondary small amplitude cycles. The effect of the small amplitude strain cycles on the low cycle fatigue life of these steel H-piles has not been extensively studied yet. Accordingly, to investigate the effect of the small amplitude strain cycles on the low cycle fatigue ...
Effect of approach channel shape on theformation of vortices at single-horizontal intakes
Sönmez, Can Metin; Göğüş, Mustafa; Department of Civil Engineering (2019)
In an experimental setup of a water intake structure composed of a reservoir-pipe system, the formation of air-entraining vortices under symmetric flow conditions were investigated for different approach channel shapes. In the first set of the experiments the approach channel walls were kept parallel to each other and be perpendicular to the head-wall of the intake structure. In the following sets of the experiments these walls were located at different angles to the head-wall. A series of experiments were ...
Effect of roughness on flow measurements in sloping rectangular channels with free overfall
Fırat, Can Ersen; Tiğrek, Şahnaz; Department of Civil Engineering (2004)
The characteristics of the subcritical, critical and supercritical flows at the rectangular free overfall were studied experimentally to obtain a relation between the brink depth and the flow rate. A series of experiments were conducted in a tilting flume with wide range of flow rate and two bed roughness in order to find the relationship between the brink depth, normal depth, channel bed slope and bed roughnesses. An equation was proposed to calculate the flow rate if only the brink depth, roughness, and c...
Citation Formats
T. Akcaoglu, M. Tokyay, and T. Celik, “Effect of coarse aggregate size and matrix quality on ITZ and failure behavior of concrete under uniaxial compression,” CEMENT & CONCRETE COMPOSITES, pp. 633–638, 2004, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/31909.