Stability and instability of foamed concrete

Jones, M. R.; Ozlutas, Kezban; Li, Zheng

doi:10.1680/macr.15.00097

Cited by 145 publications

(57 citation statements)

References 8 publications

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“…As compared with solids, it is a composite of air voids and hardened cement paste or mortar. In extremity, the air content can be higher than 85% [1]. Due to its high porosity, the foam concrete density ranges from 0.3 to 1.6 g/cm 3 [2], leading to a low strength ranging between 30 and 1500 psi [3,4].…”

Section: Introductionmentioning

confidence: 99%

Measuring Young’s Modulus of Low-Density Foam Concrete Using Resonant Frequency

Shen¹,

Lange²

2019

Preprint

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Foam concrete is a construction material with controllable low strength and untraditional physical properties. Its highly crushable nature leaves it a niche as an engineered energy-absorbing material in many value-added applications; however, fundamental understanding of the material properties is crucial. As foam concrete is highly cellularized and ductile, conventional concrete testing methods such as compression test are insufficient to characterize the key material attributes of foam concrete, especially when the foam density is low. The resonant frequency test (ASTM C215) is specified for evaluating dynamic Young’s modulus of normal concrete. Inspired by the non-destructive feature of this test, we investigate the possibility of using the resonant frequency test to continuously monitor the modulus build-up of foam concrete with age. For the representativeness of the samples, three variables are considered in material design—bulk density ranging from 0.4 to 1.2 g/cm3, water to cementitious materials ratio of 0.42 and 0.47, and fly ash replacement of 10 and 30% by weight of cement. After examining the different vibration modes, the fundamental transverse frequency is determined most suitable for interpreting the foam modulus. The experimental results demonstrate good accuracy of using this approach for the measurement of different samples. It is also confirmed that, for a given foam concrete, the foam modulus can be predicted by knowing the foam density and solid modulus of its base cement paste, which provides an important insight for the further studies and real applications of foam concrete.

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Section: Introductionmentioning

confidence: 99%

Measuring Young’s Modulus of Low-Density Foam Concrete Using Resonant Frequency

Shen¹,

Lange²

2019

Preprint

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“…It has been reported that foam concrete with fine aggregates shows a greater tendency of shrinkage, and ensuring good curing is critical [12,22]. It is generally understood that greater sand or particle content reduces the foam stability, which usually causes strength reduction in foam concrete [18,[23][24][25]. For most cases, a small amount of inclusion of finer particles results in a higher strength of foam concrete.…”

Section: Introductionmentioning

confidence: 99%

Crushing Performance of Ultra-Lightweight Foam Concrete with Fine Particle Inclusions

Shen

Lange

2019

Applied Sciences

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Foam concrete is a low-density controlled strength material that can potentially be used for accommodating different types of particles—recycled fine aggregate being an example. The paste matrix of this material has a cellular microstructure, and bulk performance is readily affected by the inclusion of fines. To study the effect of inclusion of fines on mechanical performance and foam structure of foam concrete, a group of 0.55 g/cm3 foam–sand composite mixtures with high-volume fly ash replacement are investigated. The elastic modulus is measured by a vibrational frequency test. The crushing mechanics are determined by the load-displacement response from a penetration test. The effect of particle inclusion on the foam concrete microstructure is characterized using micro computed tomography. The results indicate that use of fine-graded sand particles at a small dosage simultaneously reduces cement content and enhances the crushing performance, however poor material performance is observed for a high sand content. The cellular structure of the foam–sand composite, and thus its mechanical behavior, can be substantially diminished by larger sand particles, especially when the particle size is larger than the voids in foam.

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“…In contrast to addition of gas-forming chemicals, the use of foaming agents in producing the foam concrete has a higher potential for application in 3D-printing. This is mostly explained by the fresh and hardened properties' relative ease of adjustment by varying row materials and chemical admixtures [1,2,21,23,32,33].…”

Section: Introductionmentioning

confidence: 99%

Material Design and Performance Evaluation of Foam Concrete for Digital Fabrication

Markin

Nerella

Schröfl

et al. 2019

Preprint

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3D-printing with foam concrete, which is known for its distinct physical and mechanical properties, has not yet been purposefully investigated. The article at hand presents a methodological approach for the mixture design of 3D-printable foam concretes and a systematic investigation of the potential application of this type of material in digital construction. Three different foam concrete compositions with water-to-binder ratios between 0.33 and 0.36 and having densities of 1100 to 1580 kg/m³ in the fresh state were produced with a pre-foaming technique using a protein-based foaming agent. Based on the fresh-state tests, including 3D-printing as such, an optimum composition was identified and its compressive and flexural strengths were characterised. The printable foam concrete showed compressive strength above 10 MPa and low thermal conductivity, which make it suitable for 3D-printing applications, while fulfilling both load-carrying and insulating functions.

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Stability and instability of foamed concrete

Cited by 145 publications

References 8 publications

Measuring Young’s Modulus of Low-Density Foam Concrete Using Resonant Frequency

Measuring Young’s Modulus of Low-Density Foam Concrete Using Resonant Frequency

Crushing Performance of Ultra-Lightweight Foam Concrete with Fine Particle Inclusions

Material Design and Performance Evaluation of Foam Concrete for Digital Fabrication

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