Very high early strength of microwave cured concrete

Leung, Christopher Kin Ying; Pheeraphan, Thanakorn

doi:10.1016/0008-8846(94)00121-e

Cited by 68 publications

(22 citation statements)

References 2 publications

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“…This concrete attains sufficient strength in short curing time, so the moulds can be reused, and the final products can be rapidly delivered to the site [7]. For the conventional heating technique, heat is distributed in the specimen from the exterior to the interior leading to the non-uniform and long heating period to attain the required temperature.…”

Section: Introductionmentioning

confidence: 99%

Role of microwave radiation in curing the fly ash geopolymer

Chindaprasirt

Rattanasak

Taebuanhuad

2013

Advanced Powder Technology

134

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Section: Introductionmentioning

confidence: 99%

Role of microwave radiation in curing the fly ash geopolymer

Chindaprasirt

Rattanasak

Taebuanhuad

2013

Advanced Powder Technology

134

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“…The optimum time between the start of mixing and application of microwave curing (delay time) for developing very high early strength concrete was found to be 30 min, within the investigated range of 20-61 min [9]. Similarly the results of Makul and Agrawal [11] produced optimum compressive strength with a delay time of 30 min.…”

Section: Casting and Curingmentioning

confidence: 56%

“…Less than 1 h of microwave exposure applied in the first stage of hydration is sufficient to achieve the desired curing temperature [5][6][7]. There is already considerable research [8][9][10][11][12] on the use of early age microwave curing to accelerate strength development of concrete. The expected advantages of microwave curing have led to research around the world on developing microwave prototype systems [13][14][15] for commercial use.…”

Section: Introductionmentioning

confidence: 99%

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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“…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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Very high early strength of microwave cured concrete

Cited by 68 publications

References 2 publications

Role of microwave radiation in curing the fly ash geopolymer

Role of microwave radiation in curing the fly ash geopolymer

Bond of steel reinforcement with microwave cured concrete repair mortars

Bond between microwave cured repair and concrete substrate

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