Determination of optimal process for microwave curing of concrete

Leung, Christopher Kin Ying; Pheeraphan, Thanakorn

doi:10.1016/s0008-8846(97)00015-x

Cited by 61 publications

(21 citation statements)

References 4 publications

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“…5 and 7 shows that the percentages of compressive strength and bond strength reduction with microwave curing are similar for each repair material. Reduction in long term compressive strength due to microwave curing is previously reported by other researchers [10,31,32]. It is due to the effect of the short period of high temperature exposure at early age on long-term strength development.…”

Section: Effect Of Microwave Curing On Compressive Strengthsupporting

confidence: 59%

Bond of steel reinforcement with microwave cured concrete repair mortars

2017

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This paper investigates the effect of microwave curing on the bond strength of steel reinforcement in concrete repair. Pull-out tests on plain mild steel reinforcement bars embedded in four repair materials in 100 mm cube specimens were performed to determine the interfacial bond strength. The porosity and pore structure of the matrix at the steel interface, which influence the bond strength, were also determined. Test results show that microwave curing significantly reduces the bond strength of plain steel reinforcement. The reduction relative to normally cured (20°C, 60% RH) specimens is between 21 and 40% with low density repair materials and about 10% for normal density cementitious mortars. The corresponding compressive strength of the matrix also recorded similar reduction and microwave curing resulted in increased porosity at the interface transition zone of the steel reinforcement.A unique relationship exists between bond strength and both compressive strength and porosity of all matrix materials. Microwave curing reduced shrinkage but despite the wide variation in the shrinkage of the repair mortars, its effect on the bond strength was small. The paper provides clear correlations between the three parameters (compressive strength, bond strength and porosity), which are common to both the microwave and conventionally cured mortars. Therefore, bond-compressive strength relationships used in the design of reinforced concrete structures will be also valid for microwave cured elements.

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Section: Effect Of Microwave Curing On Compressive Strengthsupporting

confidence: 59%

Bond of steel reinforcement with microwave cured concrete repair mortars

2017

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“…Optimisation of the process is clearly required, tailored to the material to be heated, both in terms of applied power and residence time within the cavity to avoid such outcomes. Indeed by optimising the curing regime, the same workers later reported that early strength gains could be achieved, without affecting long-term strength [40].…”

Section: Accelerated Curingmentioning

confidence: 99%

Microwave processing of cement and concrete materials – towards an industrial reality?

Buttress

Jones

Kingman

2015

Cement and Concrete Research

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Each year a substantial body of literature is published on the use of microwaves to process cement and concrete materials. Yet to date, very few if any have lead the realisation of a commercial scale industrial system and is the context under which this review has been undertaken.The state-of the-art is evaluated for opportunities, and the key barriers to the development of new microwave-based processing techniques to enhance production, processing and recycling of cement and concrete materials. Applications reviewed include pyro-processing of cement clinker; accelerated curing, non-destructive testing and evaluation (NDT&E), and end-of-life processing including radionuclide decontamination.

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“…The temperature can be controlled to provide optimum curing and minimise deleterious effects on hydration products and microcracking. It reduces setting time and increases early age strength of cement based repair materials [4,[8][9][10][11][12][13][14][15][16][17] thereby preventing disruption and delays by shortening the required curing time of patch repairs in concrete structures such as bridge decks and airport runways.…”

Section: Introductionmentioning

confidence: 99%

Bond between microwave cured repair and concrete substrate

2017

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The bond strength between a concrete substrate and repair patch is critical to its durability. This paper investigates the effect of microwave curing the freshly applied repair, for 45 min at 132 Watts, on the 28 day bond strength between substrate concrete and different commercial repair materials. The repairs were applied at different ambient temperatures of 20, 10, 2 and -5°C. Tensile split tests on repaired cube specimens were performed to determine the interfacial bond strength. The ability of microwave curing to prevent the detrimental effects of freezing at early age on the bond and compressive strength of repair patches is investigated. Experimental results show that microwave curing prevents loss of long term (28 day) repair/substrate bond strength of repair materials applied at freezing temperatures (-5°C), relative to the repairs applied at higher temperatures (2-20°C), except one lightweight repair formulation. In comparison, the control samples (non-microwave cured) of repairs applied at -5°C suffered severe loss of bond strength and compressive strength due to early age freezing. In addition, no adverse effects on the bond strength and a small reduction of 6.75% in the 28 day compressive strength are observed in the early age microwave cured repairs applied at ambient temperatures of 2-20°C. The repair/substrate bond strength is independent of the compressive strength of the repair material at all temperatures of repair application. Microwave curing can accelerate the concrete repair process and facilitate construction activity in cold weather.

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Determination of optimal process for microwave curing of concrete

Cited by 61 publications

References 4 publications

Bond of steel reinforcement with microwave cured concrete repair mortars

Bond of steel reinforcement with microwave cured concrete repair mortars

Microwave processing of cement and concrete materials – towards an industrial reality?

Bond between microwave cured repair and concrete substrate

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