The influence of new and used formwork coated with different release agents on the appearance of the formed concrete surface

Savukaitis, Giedrius; Daukšys, Mindaugas; Juočiūnas, Svajūnas; Grinys, Audrius; Kriptavičius, Dalius

doi:10.1016/j.jobe.2021.102807

Cited by 5 publications

(2 citation statements)

References 26 publications

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“…When the sand mould is used to cast concrete, the sand particles on the mould surface may be absorbed by the fresh concrete or attached to the surface of concrete element, which may result in poor surface finish and difficulty in demoulding. The quality of the formed concrete surface finish mainly depends on the type of release agent and the type of form face material (Savukaitis et al , 2021). Thus, the selection of a proper release agent is particularly important for casting concrete using the proposed sand mould.…”

Section: Methodsmentioning

confidence: 99%

A sustainable formwork system based on ice pattern and sand mould for fabricating customised concrete components

Lin

Xie

2022

RPJ

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Purpose Optimised concrete components are often of complex geometries, which are difficult and costly to cast using traditional formworks. This paper aims to propose an innovative formwork system for optimised concrete casting, which is eco-friendly, recyclable and economical. Design/methodology/approach In the proposed formwork system, ice is used as mould pattern to create desired geometry for concrete member, then sand mould is fabricated based on the ice pattern. A mix design and a mixing procedure for the proposed sand mould are developed, and compression tests are also performed to ensure sufficient strength of the sand mould. Furthermore, surface preparation of the sand mould is investigated for easy demoulding and for achieving good concrete surface quality. Additionally, recyclability of the proposed sand mould is tested. Findings The proposed mix design and mixing procedure can provide sufficient strength for sand mould in concrete casting. The finished components exhibit smooth surfaces and match designed geometries, and the proposed sand mould can be fully recycled with satisfactory strength. Originality/value To the best of the authors’ knowledge, this is the first study that combines ice pattern and sand mould to create recyclable formwork system for concrete casting. The new techniques developed in this research has great potential to be applied in the fabrication of large-scale concrete structures with complex geometries.

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Section: Methodsmentioning

confidence: 99%

A sustainable formwork system based on ice pattern and sand mould for fabricating customised concrete components

Lin

Xie

2022

RPJ

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“…The standard techniques to obtain the samples (for example, cubes of side 5 cm prepared in steel molds) are suitable for the assessment of their mechanical parameters. The use of steel molds typically requires an application of a demolding agent such as a mineral oil to avoid the samples adhering to the molds [20,22,23]. This demolding agent necessarily contacts the concrete samples, so altering their surfaces.…”

Section: Introductionmentioning

confidence: 99%

Anti-adherent Molds Yield Hydraulic Concrete Samples Suitable for Assessments of Surface and Water Absorption

Mora¹,

Castellón²

2021

J. Civ. Eng. Constr.

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To assess several quality parameters of hydraulic concrete, cubic samples of this material are commonly assembled in engineering laboratories using molds. It is ubiquitous the use of cubic metallic molds of volume 125 cm3; these molds require the application of demolding substances (such as oils) on their surfaces to avoid the adhesion of the final hardened concrete sample to the molds. Despite this common practice suitable for evaluating mechanical traits of the materials, the use of a demolding agent spoils the concrete samples for the assessment of surface and water absorption parameters. To overcome this difficulty, we propose a new anti-adherent cubic mold that requires no demolding agent. The construction of the new mold based on anti-adherent polytetrafluoroethene (PTFE, Teflon®) is described with its use. To assess the claimed advantages of the new anti-adherent molds in testing surface and water diffusion traits of concrete samples, experiments on water contact angles, rates of water absorption and drying were performed on concrete specimens obtained with the classic and the new PTFE molds. It was proved the advantage of the anti-adherent mold over common metallic molds. The use of an oil as demolding agent in the concrete samples assembled in metallic molds produced conspicuous differences of water contact angles and absorption in comparison to clean concrete samples produced with PTFE molds.

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Effect of double-layer formwork curing on the early temperature field and properties of precast concrete components in environments with large diurnal temperature variations

Tong,

Kong,

Duan

et al. 2024

Low-carbon Mater. Green Constr.

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An efficient double-layer formwork curing method using an “inner supporting formwork + outer insulation formwork” was proposed in this study to address the early cracking of precast concrete components in high altitude regions. Steel and plywood formwork were designed as inner support formwork, while polystyrene (PS) and polyurethane (PU) were used as outer insulation formwork. Indoor experiments and two finite element methods (The complete simulation method focuses on computational accuracy, and the equivalent simulation method emphasizes computational efficiency) were employed to analyze the evolution of the concrete temperature field under different double-layer formwork curing methods throughout the curing period, combined with compressive strength and pore structures testing. The results show that steel + 5-mm-thick PU insulation formwork curing method can significantly mitigate the impact of large diurnal temperature variations on the internal temperature of concrete. Unlike traditional steam-curing, this method does not deteriorate the pore structure or compressive strength of the concrete. This study is of great significance in addressing the problem of early cracking of precast concrete components exposed to large diurnal temperature vriations in high altitude regions.

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The influence of new and used formwork coated with different release agents on the appearance of the formed concrete surface

Cited by 5 publications

References 26 publications

A sustainable formwork system based on ice pattern and sand mould for fabricating customised concrete components

A sustainable formwork system based on ice pattern and sand mould for fabricating customised concrete components

Anti-adherent Molds Yield Hydraulic Concrete Samples Suitable for Assessments of Surface and Water Absorption

Effect of double-layer formwork curing on the early temperature field and properties of precast concrete components in environments with large diurnal temperature variations

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