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1
Experimental Study of Steel Fiber Concrete Slabs Part I: Behavior under Uniformly Distributed Loads

Ellouze, Ali,Ouezdou, Mongi Ben,Karray, Mohammed Ali Korea Concrete Institute 2010 International Journal of Concrete Structures and M Vol.4 No.2
- 원문보기
This article aims to study the effects of adding steel fibers to concrete on the mechanical behavior of steel fiber concrete (SFC) slabs. After formulating the SFC, an experimental work was, first, conducted on $160\;{\times}\;320$ mm cylindrical specimens and $70\;{\times}\;70\;{\times}\;280$ mm prisms. Then, this study was carried out on 20 rectangular $1,100\;{\times}\;1,100\;{\times}\;60$ mm small slabs submitted to a distributed load. Two types of fibers with hooked ends were used: long fibers (LF) of a length of 50 mm and short fibers (SF) of a length of 35 mm. The studied parameters are compressive and tensile strengths and Young's modulus. Plain concrete (PC) small slabs were also prepared to be compared to the SFC specimens. The results showed that the compressive strength of SFC increased up to 25% while the splitting tests showed an improvement of the SFC reaching 45%. Tests on SFC small slabs also showed that a smaller deflection is obtained with respect to PC, which indicates an improvement in strength (up to 100%), in ductility and in resistance to cracking. The LF gives a better improvement in strength than the SF for a 70% $kg/m^3$ of steel proportioning.
2
Experimental Study of Steel Fiber Concrete Slabs Part I

Ali Ellouze,Mongi Ben Ouezdou,Mohammed Ali Karray 한국콘크리트학회 2010 International Journal of Concrete Structures and M Vol.4 No.2
- 원문보기
This article aims to study the effects of adding steel fibers to concrete on the mechanical behavior of steel fiber concrete (SFC) slabs. After formulating the SFC, an experimental work was, first, conducted on 160 × 320 mm cylindrical specimens and 70 × 70 × 280 mm prisms. Then, this study was carried out on 20 rectangular 1,100 × 1,100 × 60 mm small slabs submitted to a distributed load. Two types of fibers with hooked ends were used: long fibers (LF) of a length of 50 mm and short fibers (SF) of a length of 35 mm. The studied parameters are compressive and tensile strengths and Young"s modulus. Plain concrete (PC) small slabs were also prepared to be compared to the SFC specimens. The results showed that the compressive strength of SFC increased up to 25% while the splitting tests showed an improvement of the SFC reaching 45%. Tests on SFC small slabs also showed that a smaller deflection is obtained with respect to PC, which indicates an improvement in strength (up to 100%), in ductility and in resistance to cracking. The LF gives a better improvement in strength than the SF for a 70% kg/m³ of steel proportioning.
3
Excellent Laundry Detergent Compatibility and High Dehairing Ability of the Bacillus pumilus CBS Alkaline Proteinase (SAPB)

Bassem Jaouadi,Semia Ellouz-Chaabouni,Mamdouh Ben Ali,Ezzedine Ben Messaoud,Belgacem Naili,Abdelhafidh Dhouib,Samir Bejar 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.4
The newly Tunisian soil-isolated bacterium, producing the alkaline proteinase termed SAPB that was already purified and characterized [1], was assigned as Bacillus pumilus CBS strain on the basis of biochemical properties and 16S rRNA gene sequencing. The maximum protease activity recorded after 24 h of incubation in an optimized medium at 37°C was 6,500 U/mL in shaking flask culture and 25,000 U/mL in fermentor. SAPB showed excellent stability and compatibility in laundry detergent retaining more than 98% of its initial activity after pre-incubation for 1 h at 40°C with Det, followed by OMO (97%), Dinol (94%), and Dixan (93%). Examination of various stained cloth pieces exhibited a remarkable efficiency in the removal of blood and chocolate stains. More interestingly, SAPB demonstrated powerful dehairing capabilities of hair removal from skin with minimal damage on the collagen and a nearly complete feather-degradation. Likewise, Bacillus pumilus CBS effectively degraded feather-meal (98.5%), chicken feather (92%), goat hair (80%), and bovine hair (68%) whereas sheep wool under went less degradation. Keratin-degradation resulted in sulfhdryl group formation (0.95~3.91 μM).