Role of demoulding agents during self-compacting concrete casting in formwork

10.1617/12670 ◽  
2005 ◽  
Vol 35 (252) ◽  
Author(s):  
C. Djelal
Keyword(s):  
Self Compacting Concrete ◽  
Concrete Casting

Role of demoulding agents during self-compacting concrete casting in formwork

2002 ◽  
Vol 35 (8) ◽  
pp. 470-476 ◽  
Author(s):  
C. Djelal ◽  
Y. Vanhove ◽  
P. De Caro ◽  
A. Magnin
Keyword(s):  
Self Compacting Concrete ◽  
Concrete Casting

scholarly journals SELF-COMPACTING CONCRETE USE FOR CONSTRUCTION WORK ENVIRONMENT SUSTAINABILITY

2012 ◽  
Vol 18 (5) ◽  
pp. 724-734 ◽  
Author(s):  
Romuald Rwamamara ◽  
Peter Simonsson
Keyword(s):  
Work Environment ◽  
Construction Industry ◽  
Musculoskeletal Injury ◽  
Construction Work ◽  
Casting Method ◽  
Self Compacting Concrete ◽  
Work Activity ◽  
Work Related ◽  
Work Tasks ◽  
Concrete Casting

Many of those working on construction sites are exposed to demanding work loads; construction workers lift and carry heavy materials and work in awkward postures. Occupational injuries and accidents due to poor ergonomics are more common in the construction industry and many times lead to human tragedies, disrupt construction processes and adversely affect the cost, productivity, and the reputation of the construction industry. In Sweden, it is reported that concrete workers have the highest relative work-related musculoskeletal injury frequency. Therefore, the use of ergonomic production methods to prevent this can have a significant human, social and financial impact. Research introduced here presents a case study of comparative analyses of ergonomic situations for concrete workers performing concrete casting processes. Three different ergonomic risk assessment methods were used to assess the physical strain, hand-arm vibration and noise affects risks involved in concrete casting work tasks. The combination of technical and managerial factors results in a system where workers are as efficient and safe as possible during their work tasks, and thus, makes the construction work environment sustainable. The aim of our research is to find practical methods to evaluate and compare two different concrete casting methods from an ergonomic perspective. The focus is on the production of cast-in-place concrete bridge constructions where the traditional concrete casting method is compared with the SCC (Self-Compacting concrete) casting method. To be able to identify work-related musculoskeletal injury risks due to concrete casting work tasks, QEC (Quick Exposure Check for musculoskeletal risks), PLIBEL (Checklist for identification for Ergonomics Hazards) and ErgoSAM (Ergonomic production technology method) methods were used. Ergonomic risks analysis methods QEC, PLIBEL and ErgoSAM have all shown capabilities to evaluate construction work activities and thus determine whether a construction work activity constitutes a musculoskeletal risk to the worker or not before any ergonomic intervention is introduced. As a result the present ergonomic risks emanating from work methods used in the traditional concrete placing can be significantly reduced with the use of self-compacting concrete (SCC) that eliminates awkward work postures, noise and hand arm vibration, thereby reducing if not eliminating musculoskeletal injuries among concrete workers during their concrete casting work tasks.

scholarly journals Bond-Slip Mechanisms of Hooked-End Steel Fibers in Self-Compacting Concrete

2008 ◽  
Vol 587-588 ◽  
pp. 877-881 ◽  
Author(s):  
Vítor M.C.F. Cunha ◽  
Joaquim Barros ◽  
José Sena-Cruz
Keyword(s):  
Analytical Model ◽  
Steel Fibers ◽  
Experimental Results ◽  
Self Compacting Concrete ◽  
Fiber Pullout ◽  
Bond Slip ◽  
Pullout Tests ◽  
Embedment Length ◽  
Frictional Bond

The experimental results of hooked-end steel fibers pullout tests on a self-compacting concrete medium are presented and discussed in this work. The influence of fiber embedment length on the fiber pullout behavior is studied. The role of the end hook of the fiber on the overall pullout behavior is also investigated by carrying out tests with fibers without its end hook, in order to separate the contribution of the frictional bond component from those derived from the mechanisms provided by the end hook of the fiber. Finally, the experimental bond-slip relationships are modeled by an analytical model.

Investigation of bond between lap-spliced steel bar and self-compacting concrete: The role of silica fume

2010 ◽  
Vol 37 (3) ◽  
pp. 420-428 ◽  
Author(s):  
Mehmet Karatas ◽  
Kazim Turk ◽  
Zulfu C. Ulucan
Keyword(s):  
Bond Strength ◽  
Silica Fume ◽  
Full Scale ◽  
Reinforcing Bars ◽  
Self Compacting Concrete ◽  
Normal Concrete ◽  
Steel Bar ◽  
Normalized Bond Strength ◽  
Constant Moment

In this study, normal concrete (NC) and four types of self-compacting concrete (SCC), in which cement was partially replaced by 5%, 10%, 15%, and 20% of silica fume (SF), were used to evaluate the effect of SF content on the bond strength of tension lap-spliced bars embedded in NC and SCC specimens. Therefore, 15 full-scale beam specimens (2000 × 300 × 200 mm3) were tested and 20 mm reinforcing bars were used with a 300-mm splice length as tension reinforcement. Each beam was designed with bars spliced in a constant moment region at midspan. It was found that the bond strength of the reinforcement embedded in SCC beams was higher than that of the reinforcement in NC beams, whilst the bond strength increased with increase in the replacement of cement by SF from 5% to 10%. Moreover, the beam specimens produced from SCC containing 5% SF had the highest normalized bond strength of 1.07 followed by SCC beams with 10% SF, 15% SF, NC beams, and 20% SF.

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