Early age fracture properties of microstructurally-designed mortars

Bella, Carmelo Di; Michel, Alexander; Stang, Henrik; Lura, Pietro

doi:10.1016/j.cemconcomp.2016.11.004

Cited by 8 publications

(4 citation statements)

References 20 publications

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“…However, at low temperatures, the third stage was not seen or was not notable because this study only investigated the age of up to 60 d, meaning that there was a lot of un-hydrated cement inside the concrete under these curing temperatures. This variation of concrete fracture parameters regarding the age was consistent with other independent investigations [34]. For example, Beygi et al [35] found that with the increase of test age from 3 to 90 d, G F and K IC increase from 0.961 MPam 0.5 to 1.448 MPam 0.5 and from 99.7 N•m −1 to 126.5 N•m −1 , respectively.…”

Section: Discussionsupporting

confidence: 89%

Fracture Properties of Concrete in Dry Environments with Different Curing Temperatures

et al. 2020

Applied Sciences

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This paper investigated the fracture properties of concrete in dry environments with different curing temperatures (5, 20, 40, and 60 °C). For each curing condition, the key fracture parameters of concrete were tested using wedge splitting specimens at five different ages (3, 7, 14, 28, and 60 d). The results show that in dry environments, the effective fracture toughness and fracture energy of concrete exposed to elevated temperatures increased at a relatively high growth rate at an early age. Nevertheless, the growth speed of effective fracture toughness and fracture energy decreased more quickly at elevated temperatures in the later stages. As a result, the concrete cured at higher temperature exhibited lower ultimate values of fracture parameters, and vice-versa. Namely, a temperature crossover effect was found in the effective fracture toughness and fracture energy of concrete under dry environments. Considering the early growth rate and ultimate values of fracture parameters, the optimum temperature suitable for concrete fracture properties development under dry condition was around 40 °C.

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Section: Discussionsupporting

confidence: 89%

Fracture Properties of Concrete in Dry Environments with Different Curing Temperatures

et al. 2020

Applied Sciences

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“…A negligible effect of the small differences of fineness between the cement and the filler on the mechanical behavior was assumed based on the original work by Termkhajornkit et al [29] who reported that the fineness had minor effect on the relation between hydration degree and porosity. This assumption is confirmed by the good agreement of the strength and elastic properties between the equivalent and real systems reported in the following sections and in the previous studies [30,32].…”

Section: Sem and Isothermal Calorimetry Measurements For MIX Design Osupporting

confidence: 85%

“…In the equivalent system, where all cement has hydrated (and the system is thus inert), the volumetric composition is similar to that in the real system. By using this approach, a static (non-aging) system is obtained that is capable of emulating specific characteristics of a real system at the corresponding age, e.g., porosity, strength, elastic properties, fracture properties [30,32,33]. Equivalent systems have been also used in [34] for assessing drying shrinkage of mortars at early ages.…”

Section: Introductionmentioning

confidence: 99%

Basic creep of cement paste at early age - the role of cement hydration

Wyrzykowski

Scrivener

Lura

2019

Cement and Concrete Research

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In this work, the uniaxial creep in compression during the first days of hydration is studied experimentally on cement pastes with w/c of 0.50. In order to assess the effect of the evolving microstructure on creep, the so-called equivalent systems are employed. In these systems, part of the otherwise unhydrated cement is replaced with inert filler (quartz powder). With this approach, non-aging systems are obtained that can emulate specific microstructural features of the real hydrating systems. Despite the very similar elastic Young's moduli of the real and their corresponding equivalent systems, the real hydrating systems experienced much higher creep in the first weeks after loading than the equivalent, inert systems. The differences in creep could be explained either by possibly different morphologies of the hydrates in the two types of systems, intrinsic aging or with the active role of the hydration process in increasing creep (dissolution theory of creep).

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“…These numerical results were successively confirmed in experiments with limestone filler [29,31] . Recently, similar considerations allowed to develop static equivalent systems to study hydration-related early-age properties, shrinkage and creep, by substituting parts of the cement with inert quartz filler [32][33][34][35]. Based on the previous considerations, it can be assumed that in general the production of low clinker high performance concretes (LCHPCs) should be possible and that these mixtures could contribute to reduce the CO 2 emissions.…”

Section: Introductionmentioning

confidence: 99%

Low clinker high performance concretes and their potential in CFRP-prestressed structural elements

Lämmlein

Messina

Wyrzykowski

et al. 2019

Cement and Concrete Composites

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Three novel low-clinker-high-performance concretes (LCHPC) with clinker replacement levels of 54, 58 and 70 % were developed to substitute high-performance concrete (HPC) in carbon-fiber-reinforcedpolymer (CFRP) prestressed structural elements. The clinker substitution was achieved by a high amount of limestone filler and smaller amounts of metakaolin and silica fume. After 28 days, the LCHPCs reached high compressive strength values, between 77 MPa and 88 MPa, and Young's moduli between 35 GPa and 44 GPa. The LCHPCs showed self-compacting properties and low creep and shrinkage in comparison to a reference HPC. A finite element analysis (FEA) of the internal stress development over time in CFRP-prestressed structural elements was performed, including creep and shrinkage. A higher prestress level was maintained in the LCHPCs compared to the reference concrete, thanks to their low shrinkage and creep. In contrast, the use of ultra-high-modulus CFRP prestressing tendons leads to increased pre-stress losses.

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Early age fracture properties of microstructurally-designed mortars

Cited by 8 publications

References 20 publications

Fracture Properties of Concrete in Dry Environments with Different Curing Temperatures

Fracture Properties of Concrete in Dry Environments with Different Curing Temperatures

Basic creep of cement paste at early age - the role of cement hydration

Low clinker high performance concretes and their potential in CFRP-prestressed structural elements

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