Factors influencing compressive strength of concrete masonry prisms

Khalaf, Fouad

doi:10.1680/macr.1996.48.175.95

Cited by 42 publications

(18 citation statements)

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“…As currently defined, the strength of masonry is governed by the strength of the blocks; i.e., the effects of mortar are underestimated, which explains why many authors have stated that the mortar does not significantly affect the strength of masonry [9,14,19,24].…”

Section: G Mohamad | F S Fonseca | a T Vermeltfoort | A Lubeckmentioning

confidence: 99%

“…In contrast, structural masonry is considered anisotropic and has not received the same attention as its concrete counterpart. Only a few studies have been conducted on the failure mechanism of masonry under a complex state of stresses and these studies have focused on the testing of the components [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. For concrete block masonry mortar is usually the soft component due to its high water-cement ratio and may actually control the deformation of the masonry [27][28].…”

Section: Introductionmentioning

confidence: 99%

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Stiffness plasticity degradation of masonry mortar under compression: preliminar results

Mohamad

Fonseca

Vermeltfoort

et al. 2018

Rev. IBRACON Estrut. Mater.

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ResumoThe main goal of this research is to determine the mechanical properties of bedding mortar by assessing the mortar damage onset, the stiffness plasticity degradation and the apparent Poisson´s ratio under compression. Two mortar types, 1:0.5:4 and 1:1:6 (cement:lime:sand ratio), were used and tested at 28 days; specimens had diameter-to-height (d/h) ratios of 0.3 and 1.0. These diameter-to-height (d/h) ratios were chosen to evaluate the effect of confinement caused by the friction between the steel plates of the testing machine and the sample. Numerical models were developed, and their response compared with the experimental results. From the experimental results, it was concluded that there are meaningful differences in their responses with weak and strong mortar types and different d/h ratios. The d/h ratio influences the relationship between the stress and strength and the apparent Poisson´s ratio of the specimen, which is defined herein as the ratio of the horizontal to vertical strain, regardless of cracking of the specimen. The mortar damage onset and stiffness plasticity degradation for both mortar types and d/h ratio are different and depend on the stress/ strength ratio level. All samples with a d/h ratio of 0.3 show a constant decrease in the volumetric strain until failure but with negligible expansion on the horizontal deformation. In contrast, samples with a d/h ratio of 1.0 present an increase of stiffness after development of the first crack, which causes the increase of the sample volume. Numerical simulation and experimental results for mortar 1:0.5:4 with a d/h ratio of 0.3 are similar until approximately 10 MPa, after which the numerical results diverge from the experimental results. For the d/h ratio of 1.0, the vertical strain results are also similar, but the horizontal strains results near failure are very different. The model can not represent the nonlinear increase of the horizontal strain near failure probably because the crack propagation and the stiffness plasticity degradation could not be controlled. For mortar 1:1:6, vertical strains from numerical and experimental results are similar, but again the model can not reproduce the nonlinear increase of horizontal strain near failure.Keywords: bedding mortar, damage onset, vertical strain, horizontal strain, strain difference, confinement effect.O objetivo principal desta pesquisa é determinar as propriedades mecânicas da argamassa de assentamento à compressão, avaliando o início do dano, perda de rigidez e variação do coeficiente de Poisson aparente. Foram testados dois tipos de argamassa, com traços em volume de 1:0,5:4 e 1:1:6 (cimento, cal e areia), testadas aos 28 dias, com corpos de prova de prova cilíndricos com duas relações diâmetro/altura (d/h), de 0,3 e 1,0. Estas relações diâmetro/altura foram escolhidas de forma a avaliar o efeito do confinamento causado pelo atrito entre os pratos de aplicação de carga da prensa e o corpo de prova. Foram desenvolvidos, também, modelos numéricos de maneira a confrontar os res...

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Section: G Mohamad | F S Fonseca | a T Vermeltfoort | A Lubeckmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stiffness plasticity degradation of masonry mortar under compression: preliminar results

Mohamad

Fonseca

Vermeltfoort

et al. 2018

Rev. IBRACON Estrut. Mater.

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“…En cuanto a la mampostería con concreto de relleno, aunque no se cuenta con suficientes datos nacionales, de un estudio realizado por Khalaf (1996) se concluye que aumentar f' mortero tiene un efecto insignificante sobre el valor de f' m .…”

Section: Resistencia a Compresión De La Mampostería De Concretounclassified

“…Estudios realizados referentes al efecto de f ' g sobre f ' m (Boult, 1979;Abril;Khalaf, 1996) señalan que igualar las características de deformación del concreto de relleno con las del bloque es más efectivo, en términos de f ' m , que aumentar f ' g . Según estos estudios, la situación anterior se logra al utilizar un concreto de relleno entre 45 % y 50 % más resistente que el bloque; sin embargo, su costo lo hace poco práctico.…”

Section: Resistencia a Compresión Del Concreto De Relleno F' Gunclassified

Propiedades a compresión de la mampostería de bloques de concreto

Carro

2011

Ingeniería

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“…al (2013), Hamid (1979 , 1983), Gayed et al (2004), Gaynor et. al (1987, Khalaf (1996), Khalaf et. al (1994), Maurenbrecher (1980), Mohamad et.…”

Section: Effect Of Unit Compressive Strength (F Bl )mentioning

confidence: 96%

The Size Effect and Strain Effect in Reinforced Masonry

Sarhat¹

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The research described in this thesis focuses on improving our understanding of the behaviour of reinforced concrete masonry subjected to shear. All shear design methods in current masonry building codes are empirically based, and have been shown to produce widely varying predictions of shear strengths of masonry walls, beams and columns. Furthermore, the research community acknowledges that there is little to no consensus on the exact mechanisms of shear transfer in masonry elements, thereby slowing the replacement of empirical design expressions with more rational approaches. Given that shear failures can be brittle and sudden, with little to no warning of impending failure; experimental research focusing on these two issues is of primary importance.An extensive experimental program consisting load-testing fifteen large-scale reinforced masonry beams is presented in this thesis. The results definitively show that principles that ix

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Factors influencing compressive strength of concrete masonry prisms

Cited by 42 publications

References 0 publications

Stiffness plasticity degradation of masonry mortar under compression: preliminar results

Stiffness plasticity degradation of masonry mortar under compression: preliminar results

Propiedades a compresión de la mampostería de bloques de concreto

The Size Effect and Strain Effect in Reinforced Masonry

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