Strength and deformability of hollow concrete blocks: correlation of block and cylindrical sample test results

Resistência e deformabilidade de blocos vazados de concreto: correlação entre os resultados experimentais de blocos e corpos-de-prova cilíndricos

Strength and deformability of hollow concrete blocks: correlation of block and cylindrical sample test results

Resistência e deformabilidade de blocos vazados de concreto: correlação entre os resultados experimentais de blocos e corpos-de-prova cilíndricos

C. S. Barbosa ^I ; J.b . Hanai ^{I I}

^IPh.D. Student, School of Engineering at Sao Carlos, Department of Structural Engineering, University of Sao Paulo, [e-mail] . Av. do Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos, Brazil

^IIProfessor, School of Engineering at Sao Carlos, Department of Structural Engineering, University of Sao Paulo, [e-mail] . Av. do Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos, Brazil

ABSTRACT

This paper deals with correlations among mechanical properties of hollow blocks and those of concrete used to make them. Concrete hollow blocks and test samples were moulded with plastic consistency concrete, to assure the same material in all cases, in three diferente levels of strength (nominally 10 N/mm², 20 N/mm² and 30 N/mm²). The mechanical properties and structural behaviour in axial compression and tension tests were determined by standard tests in blocks and cylinders. Stress and strain analyses were made based on concrete’s modulus of elasticity obtained in the sample tests as well as on measured strain in the blocks’ face-shells and webs. A peculiar stress-strain analysis, based on the superposition of effects, provided an estimation of the block load capacity based on its deformations. In addition, a tentative method to preview the block deformability from the concrete mechanical properties is described and tested. This analysis is a part of a broader research that aims to support a detailed structural analysis of blocks, prisms and masonry constructions.

Keywords: structural masonry, concrete block, mechanical properties, strength, deformability.

RESUMO

Este trabalho trata das correlações entre as propriedades mecânicas de blocos vazados e do concreto que o constitui. Foram moldados blocos vazados e corpos-de-prova com concreto de consistência plástica para que fosse garantido o mesmo material em todos os casos, para três diferentes níveis de resistência (10 N/mm², 20 N/mm² e 30 N/mm²). As propriedades mecânicas e o comportamento estrutural sob compressão axial e tração foram obtidos por meio de ensaios padronizados com blocos e corpos-de-prova. Uma análise de tensões e deformações foi realizada com base no módulo de elasticidade do concreto obtido no ensaio com corpo-de-prova e também por meio da medição da deformação nas paredes longitudinais e septos transversais dos blocos. Uma análise peculiar sobre a relação tensão-deformação, baseada na superposição dos efeitos, permitiu a previsão da capacidade de carga do bloco a partir dos valores de suas deformações. Além disso, um método de previsão da deformabilidade do bloco a partir das propriedades mecânicas do concreto e descrito e avaliado. Este estudo é parte de uma pesquisa mais ampla que objetiva estudar detalhadamente do comportamento estrutural de blocos, prismas e paredes.

Palavras-chave: alvenaria estrutural, bloco de concreto, propriedades mechanicas, resistência, deformabilidade.

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Full text avaliable only in PDF.

Received 06/06/2007

Accepted 16/01/2009

Available Online 03/04/2009

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Publication Dates

• Publication in this collection
  18 Sept 2014
• Date of issue
  Mar 2009

History

• Accepted
  16 Jan 2009
• Received
  06 June 2007