Rebound hammer test to estimate compressive strength of heat exposed concrete

Panedpojaman, Pattamad; Tonnayopas, Danupon

doi:10.1016/j.conbuildmat.2018.03.179

Cited by 39 publications

(15 citation statements)

References 18 publications

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“…Whereas FT specimens experienced a greater loss in surface hardness at 800°C temperature. The surface hardness values of PT specimens are in close agreement with the results of Panedpojaman and Tonnayopas (2018).…”

Section: Resultssupporting

confidence: 84%

Residual properties of normal-strength concrete subjected to fire and sustained elevated temperatures: A comparative study

Sachin¹,

Suresh²

2020

JSFE

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Purpose Concrete is a widely used construction material which can be prepared using locally available resources (aggregates, cement and water) by following relevant standard guidelines. The residual properties of concrete determined by heating in an electric furnace may not produce a similar effect of fire. The purpose of this paper is to compare the effect of a fire with that coming from the exposure of normal strength concrete to predetermined reference temperatures, for which two sets of specimens were heated in a fire furnace provided with gas burners and an electric furnace. Design/methodology/approach The concrete cubes and cylinders were subjected to 200oC, 400oC, 600oC and 800oC temperature in a gas-controlled fire furnace and an electric furnace for 2 h. The physical properties and mechanical properties of concrete were determined after cooling the specimens in air. The quality of concrete specimens was determined using the ultrasonic pulse velocity test, and surface hardness of the heat-exposed cubes was recorded using the Schmidt rebound hammer. Findings The fire-exposed specimens were found to have lower residual compressive strength, tensile strength and higher porosity/voids/internal cracks than the specimens heated in an electric furnace at the same temperature. Further, a good agreement with compressive strength and rebound numbers was observed for each of the two heating systems (flames coming from gas burners and electric furnace). Originality/value Normal strength concrete specimens exposed to heat in an electric furnace will not give the same effect of fire having the same maximum temperature. Further, it is noticed that concrete subjected to elevated temperature is sensitive to heating modalities, be it the flames of a gas furnace or the radiation of an electric furnace.

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Section: Resultssupporting

confidence: 84%

Residual properties of normal-strength concrete subjected to fire and sustained elevated temperatures: A comparative study

Sachin¹,

Suresh²

2020

JSFE

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“…According to standard [6] aggregate obtained from recycling is fully valuable material, which requires testing and assessment. It is also a good method for improving both ecological and economic aspects of the concrete production sector [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effect of High Temperatures on the Impact Strength of Concrete Based on Recycled Aggregate Made of Heat-Resistant Cullet

2020

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The article presents results obtained during testing of concrete based on CEM I 42.5R Portland cement, fine and coarse aggregate, glass, volatile ash, and superplastifier. The concrete mixture was modified using filler consisting of bromosilicate heat resistant cullet. Recycled aggregate was added to the batch. Samples for the need of testing were produced as (100 × 100 × 100) mm cubes. Before commencing proper tests, samples have been heated within the temperature range of 20–800 °C. Tests carried out during the proper testing procedure included tests of compressive strength, elevated temperature, impact strength, as well as macroscopic tests of the contact area. The obtained test results have provided proof of there being a possibility of producing special concrete, modified by products obtained from heat resistant cullet. This type of is generally characterized by satisfactory performance parameters. The average compressive strength for concrete modified by a 10% of heat resistant cullet was determined as 43.6 MPa and 48.3 MPa respectively after 28 and 180 days of curing.

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“…As with carbonation, high temperatures also affect surface hardness and compressive strength. Panedpojaman and Tonnayopas [23] found that high temperatures are detrimental to compressive strength. If concrete is exposed to fire, up to about 420 ∘C the rebound number does not change in any major way, but compressive strength is lost.…”

Section: Introductionmentioning

confidence: 99%

Characteristic Curve and Its Use in Determining the Compressive Strength of Concrete by the Rebound Hammer Test

2019

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During the construction of concrete structures, it is often useful to know compressive strength at an early age. This is an amount of strength required for the safe removal of formwork, also known as stripping strength. It is certainly helpful to determine this strength non-destructively, i.e., without any invasive steps that would damage the structure. Second only to the ultrasonic pulse velocity test, the rebound hammer test is the most common NDT method currently used for this purpose. However, estimating compressive strength using general regression models can often yield inaccurate results. The experiment results show that the compressive strength of any concrete can be estimated using one’s own newly created regression model. A traditionally constructed regression model can predict the strength value with 50% reliability, or when two-sided confidence bands are used, with 95% reliability. However, civil engineers usually work with the so-called characteristic value defined as a 5% quantile. Therefore, it appears suitable to adjust conventional methods in order to achieve a regression model with 95% one-sided reliability. This paper describes a simple construction of such a characteristic curve. The results show that the characteristic curve created for the concrete in question could be a useful tool even outside of practical applications.

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Rebound hammer test to estimate compressive strength of heat exposed concrete

Cited by 39 publications

References 18 publications

Residual properties of normal-strength concrete subjected to fire and sustained elevated temperatures: A comparative study

Residual properties of normal-strength concrete subjected to fire and sustained elevated temperatures: A comparative study

Effect of High Temperatures on the Impact Strength of Concrete Based on Recycled Aggregate Made of Heat-Resistant Cullet

Characteristic Curve and Its Use in Determining the Compressive Strength of Concrete by the Rebound Hammer Test

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