Plastic viscosity of fresh concrete – A critical review of predictions methods

Chidiac, S.E.; Mahmoodzadeh, Fathollah

doi:10.1016/j.cemconcomp.2009.02.004

Cited by 97 publications

(25 citation statements)

References 27 publications

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“…The water to powder ratio Vw/Vp and SP% were adjusted to change the rheological properties of paste. Equations and show rheological characteristics developed by Toutou and Roussel and Chidiac and Mahmoodzadeh that satisfy both flowability and segregation resistance requirements; excellent workability was achieved by SCC, a maximum for τ paste and a minimum for η paste are essential to ensure the flowability and segregation resistance of SCC.

τ_{paste} \leq \frac{\frac{\sqrt{2} Δ ρg r^{2}}{3 δ_{mortar}}}{{((), 1 - \frac{φ}{φ_{\max}})}^{- n}},

η_{paste} \geq \frac{\frac{2 r^{2} gΔ ρ T_{f}}{9 H}}{{((), 1 - \frac{φ}{φ_{\max}})}^{- [n] φ_{\max}}},

…”

Section: Scc Mixture Design Methodsmentioning

confidence: 95%

An overview on mixture design of self‐compacting concrete

Ashish

Verma

2018

Structural Concrete

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Self-compacting concrete (SCC) was developed in 1988 and introduced by Professor H. Okamura to achieve durability of structures with low skilled laborers. The three properties of SCC that differentiates it from traditional concrete are passing ability, filling ability and segregation resistance. The present study highlights the developments concerning SCC in the period from 1995 to 2017. This information is important for researchers and professionals working in this area. SCC can be optimized to a larger extent to find the best alternative either by use of additives or tailor-made mix design. Based on different principles and parameters, design methods can be categorized into six classes namely empirical design method, statistical factorial design method, strength-based design method, rheology of paste method, particle packing method and Eco-SCC mixture design method. To develop SCC with high quality a suitable method can be chosen depending upon the situation and application.compressive strength, design mixture method, empirical, particle packing method, rheology of paste method, self-compacting concrete 1 | INTRODUCTION SCC flows into every corner of a mold, passes reinforcement and fill gaps without any need of internal or external vibration and compaction simultaneously maintaining stability without segregation and bleeding of concrete. It has the ability to compact itself only by means of its own weight. [1][2][3][4] In the early 1990s, SCC was introduced in concrete technology. 5 The properties of SCC depend on the source and the type of constituent materials and their properties. 6 The use of SCC eliminates the compacting effort and this results in reduced costs of placement, moreover, a decrease in the duration of construction improves productivity. 7 SCC is a concrete type with high workability, a high flowability and superior resistance to segregation. 8 The property of SCC to completely fill a formwork by filling gaps and to flow around reinforcement without the need of vibration or bleeding makes it significant to use. 9 A good balance between deformability and stability resulted in the successful development of SCC. Different mix design procedures were proposed for SCC that include (a) combinations of a higher volume of mineral additives and water-reducing admixture, (b) combination of water-reducing admixture and viscosity modifying agent. 10 The use of SCC reduces the noise during casting and provides better working conditions. 7,11 The applications of SCC in densely reinforced sections, that is, columns and beams in moment-resisting frames in seismic areas is necessary to ensure that all gaps in a formwork are filled. 7 The use of limestone powder as a fine additive can improve the rheological behavior of cement pastes and the combination of both limestone powder and fly ash can result in a higher packing density. 12 Eco-SCC is a SCC with a maximum total binder content of 315 kg/m 3 which can include cement, silica fume, fly ash and/or limestone filler. 13 Air-entrained SCC was designed with the u...

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τ_{paste} \leq \frac{\frac{\sqrt{2} Δ ρg r^{2}}{3 δ_{mortar}}}{{((), 1 - \frac{φ}{φ_{\max}})}^{- n}},

η_{paste} \geq \frac{\frac{2 r^{2} gΔ ρ T_{f}}{9 H}}{{((), 1 - \frac{φ}{φ_{\max}})}^{- [n] φ_{\max}}},

…”

Section: Scc Mixture Design Methodsmentioning

confidence: 95%

An overview on mixture design of self‐compacting concrete

Ashish

Verma

2018

Structural Concrete

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“…Herschel-Bulkley equation contains three parameters, one of which does not represent a physical entity. It has been shown by de Larrard et al [11] [20], Chidiac and Mahmoodzadeh [21].…”

Section: Introductionmentioning

confidence: 94%

Mathematical Modelling in Placing of Fresh Concrete

Bilgil¹

2011

ENG

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The main problem in working with fresh concrete is the aggregate segregation during filling of formwork. The segregation is strongly related to W/C (Water/Cement) ratio. The fresh concrete is usually considered as a Non-Newtonian fluid since it is a mixture of aggregate, cement and water. The flow behavior of the fresh concrete to W/C ratio plays a crucial role in the quality of the high performance concretes by affecting the flow behaviour of the fresh concrete. The aggregates in the fresh concrete usually cause segregation in the final product depending on the flow condition. In this study, the mechanism of segregation in such systems was theoretically investigated. The mould filling of fresh concrete was numerically investigated and aggregates were considered as Lagrangian particles and segregation was identified from trajectories of such particles. It was found that the aggregates were trapped at the dead zones leading to segregation in the system. The particle size and geometry of the mould was found to have significantly affect the segregation in the system.

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“…Therefore, the continuum approach is suitable to model the SCC flowing. The Bingham or Herschel-Bulkley (H-B) fluid has been widely used to describe flows of SCC and SCM [19][20][21]. In this study, the H-B model which has been implemented in OpenFoam is adopted.…”

Section: Numerical Model For Sccmentioning

confidence: 99%

Filling Capacity Evaluation of Self-Compacting Concrete in Rock-Filled Concrete

Liu

Pan

2019

Materials

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The good filling performance of self-compacting concrete (SCC) to pre-placed assembly of rocks is essential for quality of rock-filled concrete (RFC). In this study, a theoretical model is proposed to evaluate the filling capacity of SCC in porous media that is simplified to approximate the assembly of rocks. Numerical simulation of SCC flow in the porous media is carried out based on the computational fluid dynamics. The effects of yield stress of SCC and size and shape of grains in the porous media on the filling capacity of SCC are considered. The inclination of the free surface of the distribution of SCC at flow stoppage is defined to evaluate the filling capacity of SCC in the porous media. According to the theoretical model, the inclination is directly proportional to the yield stress of the SCC and the blocking effect of grains, while inversely proportional to the grain size. The numerical simulation provides consistent results with the theoretical model. The results suggest the use of rounded large rocks and SCC with low yield stress to ensure good quality of RFC.

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Plastic viscosity of fresh concrete – A critical review of predictions methods

Cited by 97 publications

References 27 publications

An overview on mixture design of self‐compacting concrete

An overview on mixture design of self‐compacting concrete

Mathematical Modelling in Placing of Fresh Concrete

Filling Capacity Evaluation of Self-Compacting Concrete in Rock-Filled Concrete

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