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Concrete strength reduction due to over compaction

Journal Article


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Abstract


  • The purpose of this study was to evaluate the effect of over-compaction on the strength of concrete with

    regards to commercial and industry practices. Normal concrete, which is commonly used in construction

    was chosen. Samples were cast using a varying vibration time and testing was performed to determine

    concrete compressive strength, air content, density and a measure for segregation. These parameters

    were used to determine the relative sensitivity of concrete to under- versus over-compaction. If segregation

    was present, it was hypothesized the results would indicate a mathematical relationship between

    the segregation and strength reduction. This relationship would allow for determination of an optimum

    vibration time range. It was found in this study there was no segregation or strength reduction in vibrated

    samples. This result proved the concrete was far more sensitive to under-compaction, with overcompaction

    not being a practical concern. It was also determined that concrete compressive strength

    and vibration time had a basically logarithmic relationship and 30 s of continuous internal vibration provided

    the most efficient result of approximately 92% of maximum strength. The study recommends

    adjustment of standard concrete vibration practice to accommodate the more efficient 30 s duration.

    Alternatively, a 1.4x ’vibration factor’ can be applied during design of compressive strength of concrete

    to accommodate the current 5–15 s vibration time window.

UOW Authors


  •   Howes, Ryan (external author)
  •   Hadi, Muhammad N. S. (external author)
  •   South, Warren J. (external author)

Publication Date


  • 2019

Citation


  • Howes, R., Hadi, M. N. S. & South, W. (2019). Concrete strength reduction due to over compaction. Construction and Building Materials, 197 725-733.

Ro Full-text Url


  • https://ro.uow.edu.au/context/eispapers1/article/3090/type/native/viewcontent

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/2085

Number Of Pages


  • 8

Start Page


  • 725

End Page


  • 733

Volume


  • 197

Place Of Publication


  • Netherlands

Abstract


  • The purpose of this study was to evaluate the effect of over-compaction on the strength of concrete with

    regards to commercial and industry practices. Normal concrete, which is commonly used in construction

    was chosen. Samples were cast using a varying vibration time and testing was performed to determine

    concrete compressive strength, air content, density and a measure for segregation. These parameters

    were used to determine the relative sensitivity of concrete to under- versus over-compaction. If segregation

    was present, it was hypothesized the results would indicate a mathematical relationship between

    the segregation and strength reduction. This relationship would allow for determination of an optimum

    vibration time range. It was found in this study there was no segregation or strength reduction in vibrated

    samples. This result proved the concrete was far more sensitive to under-compaction, with overcompaction

    not being a practical concern. It was also determined that concrete compressive strength

    and vibration time had a basically logarithmic relationship and 30 s of continuous internal vibration provided

    the most efficient result of approximately 92% of maximum strength. The study recommends

    adjustment of standard concrete vibration practice to accommodate the more efficient 30 s duration.

    Alternatively, a 1.4x ’vibration factor’ can be applied during design of compressive strength of concrete

    to accommodate the current 5–15 s vibration time window.

UOW Authors


  •   Howes, Ryan (external author)
  •   Hadi, Muhammad N. S. (external author)
  •   South, Warren J. (external author)

Publication Date


  • 2019

Citation


  • Howes, R., Hadi, M. N. S. & South, W. (2019). Concrete strength reduction due to over compaction. Construction and Building Materials, 197 725-733.

Ro Full-text Url


  • https://ro.uow.edu.au/context/eispapers1/article/3090/type/native/viewcontent

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/2085

Number Of Pages


  • 8

Start Page


  • 725

End Page


  • 733

Volume


  • 197

Place Of Publication


  • Netherlands