Estimating early-age in situ strength development of concrete slabs

Sofi, Massoud; Mendis, Priyan; Baweja, Daksh

doi:10.1016/j.conbuildmat.2011.10.019

Cited by 44 publications

(28 citation statements)

References 7 publications

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“…The latter is capable of estimating the strength evolution of conventional concrete as observed in various studies [1,12]. However, sprayed concrete often has particular characteristics that are not considered in Plowman's equation.…”

Section: (2)mentioning

confidence: 99%

Maturity method to predict the evolution of the properties of sprayed concrete

Galobardes

Cavalaro

Goodier

et al. 2015

Construction and Building Materials

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The maturity method provides a simple approach for assessing the strength evolution of concrete.Although it is already used in the precast industry, no reported applications with sprayed concrete may be found in the literature. Such concrete presents singular characteristics due to the spraying process and, in some cases, due to the introduction of accelerators that modify the kinetics of cement hydration.Consequently, the traditional equations that relate the evolution of mechanical properties and the maturity index might not apply in this case. The objective of this study is to adapt the maturity method to sprayed concrete. An experimental program was conducted with 24 concrete mixes sprayed in laboratory and tested for the evolution of temperature and compressive strength. An alternative equation was proposed to relate the maturity index and the mechanical properties. Subsequently, finite element models were developed to generalize the maturity curves considering the local design parameters.

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Section: (2)mentioning

confidence: 99%

Maturity method to predict the evolution of the properties of sprayed concrete

Galobardes

Cavalaro

Goodier

et al. 2015

Construction and Building Materials

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“…As a result, the strengthmaturity models established from the NSC test data using standard cylinders are frequently pointed out to overestimate the in situ strength of HSC, particularly under a cold temperature at an early age (Parsons and Naik 1985;Hulshizer 2001). However, the strength-maturity relationship for HSC is still an equivocal issue because of the limited available data, although the maturity method is used as an effective means of estimating strength development of in situ concrete (Sofi et al 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Construction schedules for concrete structures significantly depend on the minimum stripping time for the concrete form work and shoring and the minimum concrete strength for applying a prestressing force to a structural element (Sofi et al 2012;Vázquez-Herrero et al 2012). Thus obtaining a higher strength gain of concrete at an early age is one of the most critical concerns for shortening the construction time for concrete structures.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Strength–Maturity Models Accounting for Hydration Heat in Massive Walls

Yang

Mun

Kim

et al. 2016

Int J Concr Struct Mater

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The objective of this study was to evaluate the capability of different strength-maturity models to account for the effect of the hydration heat on the in-place strength development of high-strength concrete specifically developed for nuclear facility structures under various ambient curing temperatures. To simulate the primary containment-vessel of a nuclear reactor, three 1200-mm-thick wall specimens were prepared and stored under isothermal conditions of approximately 5°C (cold temperature), 20°C (reference temperature), and 35°C (hot temperature). The in situ compressive strengths of the mock-up walls were measured using cores drilled from the walls and compared with strengths estimated from various strength-maturity models considering the internal temperature rise owing to the hydration heat. The test results showed the initial apparent activation energies at the hardening phase were approximately 2 times higher than the apparent activation energies until the final setting. The differences between core strengths and field-cured cylinder strengths became more notable at early ages and with the decrease in the ambient curing temperature. The strength-maturity model proposed by Yang provides better reliability in estimating in situ strength of concrete than that of Kim et al. and Pinto and Schindler.Keywords: high-strength concrete, in situ strength, mock-up, hydration heat, maturity, curing temperature. List of Symbols

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“…This problem can be more prominent for e.g. in building applications such as removal of formwork or post-tensioning of elements which require early age strength to a specified level for prestressing [5]. Replacement of a portion of cement by FA is equally known to reduce the later age strength properties.…”

mentioning

confidence: 99%

“…Therefore, numerous studies have been conducted to investigate the strength development of concrete containing FA to facilitate wider use of this environmentally-friendly material in the concrete industry [5] [7]. To improve the early age strength development properties and uptake of FA based concrete, it is important to know the reactivity of the binder material used in the concrete.…”

mentioning

confidence: 99%

From Hydration to Strength Properties of Fly Ash Based Mortar

Sofi¹,

Lumantarna²,

Zhou³

et al. 2017

MSCE

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Fly ash (FA) is important alternative or supplement to cement to reduce the environmental impact of concrete industry. However, early age strength development of FA is a concern due to the slower reaction rate of FA compared to cement. This paper examines the early age hydration properties of cement paste containing typical Australian FA and establishes correlations between the degree of hydration and the early-age strength development properties of mortar mixes. All mixes have the same mixture proportion of water to binder (w:b) ratio. FA sourced from different power plants are used for the tests. Cement replacement levels of 0%, 10%, 30% and 40% by mass are considered. The degree of hydration was established from the heat production of the mixes by using isothermal calorimetry. The hydration properties were characterized by hydration curve parameters obtained from curve fitting. The results show that both hydration rate and strength of the binder materials (FA and cement) were reduced with higher replacement levels of FA contributing to a reduced hydration rate at early ages. Linear relationship could be obtained between degree of hydration and strength at early ages for all the fly ash binders.

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Estimating early-age in situ strength development of concrete slabs

Cited by 44 publications

References 7 publications

Maturity method to predict the evolution of the properties of sprayed concrete

Maturity method to predict the evolution of the properties of sprayed concrete

Comparison of Strength–Maturity Models Accounting for Hydration Heat in Massive Walls

From Hydration to Strength Properties of Fly Ash Based Mortar

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