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RISS 인기검색어
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- 저자 : Nordine Leklou (검색결과 3 건)
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Nordine Leklou,Van-Huong Nguyen,Pierre Mounanga 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4
Delayed Ettringite Formation (DEF) is seen as a form of internal sulfate attack of cementitious materials, caused by early age heating to a temperature higher than 70°C. In this paper, the effect of fly ash on delayed ettringite formation of heat-cured cementbased mortars was investigated. To fulfil the aim of this study, a portion of cement was replaced by class F-fly ash, with three different dosages (10, 20 and 30%). The mortars were heat-cured at early-age, and the tests of expansion, mechanical strength, dynamic elastic modulus, mercury porosity and thermogravimetric analysis were carried on these mortars along a period of 650 days. Additionally, Scanning Electron Microscopy (SEM) observations were realized. The results obtained highlighted the mitigation effects of fly ash on DEF: A replacement of the cement used with 20% to 30% of fly ash was efficient to eliminate the long-term swelling due to DEF. This positive impact was explained by the combined effects of the high Al2O3 content of fly ash and the portlandite consumption induced by the pozzolanic reactions.
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Blast Furnace Slag Addition Effects on Delayed Ettringite Formation in Heat-cured Mortars
Walid Deboucha,Nordine Leklou,Abdelhafid Khelidj 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.9
Reducing expansion due to Delayed Ettringite Formation (DEF) is becoming an important issue that must be taken into account, when producing heat-cured concrete. Mineral additives used as partial cement replacement should help in achieving the desired aspect. Based on an ongoing experimental program, this research emphasizes on the effect of Blast Furnace Slag (BFS) on the expansion of cement mortars caused by DEF. For this purpose, mortar prisms in which Portland cement was replaced by BFS, with three different replacement levels (10,20 and 40%) and two finenesses degree (400 and 500 m2/kg) were tested in length change, dynamic elasticity modulus and compressive strength over more than 750 days. Results showed that the efficiency of blast furnace slag in controlling expansion related to DEF was conditioned by its levels of replacement.
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Armel B. Laibi,Philippe Poullain,Nordine Leklou,Moussa Gomina,Dominique K. C. Sohounhloué 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2
The association of natural fibers and raw land soil has many advantages (thermal control, sound insulation, mechanical behavior, etc.). However, the major issue with the use of these materials is the lack of knowledge regarding their reliability and durability. In this work, we have evaluated the influence of kenaf fiber length on the mechanical and thermal properties of Compressed Earth Blocks (CEB). Fibers with length 10, 20 or 30 mm were used at mixing rate of 1.2% dry weight of soil; with the aim to enhance the mechanical and thermal properties of CEB fabricated starting from a plastic clayey soil mined in Benin. Analysis of the mechanical behavior of different Soil/Fiber formulations in terms of flexural strength demonstrated the beneficial effect of the fibers. However, the mechanical strength of CEB obtained by immersing fibers till saturation prior to incorporation into the soil greatly diminished. The higher flexural strength was obtained with fibers 30 mm long. The thermal conductivity of CEB decreased when the fiber length was raised. The results showed the real possibility to improve CEB mechanical and thermal properties by using fibers for reinforcement.
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