A Study on the Mechanical Properties of the Hybrid Fiber-Reinforced Mortar Using the Macro Steel and Micro Carbon Fibers
Gwang Hee Heo,
Jong Gun Park,
Hyung Min Jun,
Dong Ju Seo,
Sung Gon Koh
Issue:
Volume 8, Issue 6, November 2020
Pages:
128-138
Received:
29 October 2020
Accepted:
12 November 2020
Published:
19 November 2020
Abstract: In the present study, an experiment was conducted to investigate the mechanical properties such as fluidity, compressive strength and flexural performance (flexural strength and toughness) of a single fiber-reinforced mortar (FRM) using only macro steel fiber (SF) or micro carbon fiber (CF) with different material properties and SF-CF hybrid FRM using a mixture of macro SF and micro CF. The specimens incorporated macro SF and micro CF in the mix proportions of 100-0%, 75-25%, 50-50%, 25-75% and 0-100% by volume at a total fiber volume fraction of 1.0%. Their mechanical properties were further compared and reviewed with the plain mortar at 28 days of age. The experimental results of fresh mortar showed that the table flow of mortar using only macro SF was slightly reduced compared to plain mortar, whereas the table flow of mortar using only micro CF and SF-CF hybrid mortar decreased significantly with increase of micro CF. It was revealed from the test of the hardened mortar that the SF-CF=75-25% (M3) specimen showed the highest compressive and flexural strength, and the SF-CF=50-50% (M6) specimen obtained the highest flexural toughness. Therefore, it was possible to confirm the synergistic reinforcement effect of that enhanced the strength and improved the flexural performance by hybrid of macro SF and micro CF. Based on the results of this experiment, the optimal mix proportion of SF-CF hybrid FRM is proposed in this paper to improve the compressive strength, flexural strength and flexural toughness.
Abstract: In the present study, an experiment was conducted to investigate the mechanical properties such as fluidity, compressive strength and flexural performance (flexural strength and toughness) of a single fiber-reinforced mortar (FRM) using only macro steel fiber (SF) or micro carbon fiber (CF) with different material properties and SF-CF hybrid FRM us...
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Evaluating the Effects of Watershed Characteristics on River Flow for the Case of Fetam River, Ethiopia
Solomon Bogale Aynalem,
Megersa Gemechu Liben
Issue:
Volume 8, Issue 6, November 2020
Pages:
139-149
Received:
29 August 2020
Accepted:
17 September 2020
Published:
23 November 2020
Abstract: Evaluating the effects of watershed characteristics have impacted on the stream flow of the watershed by changing the magnitude of surface runoff and ground water flow. This study is mainly focusing the effects of watershed characteristics on the stream flow by changing SURQ and GWQ for the wet months (June, July, August) and dry months (January, February, March) through satellite Remote Sensing (RS) and Geographic Information System (GIS) integrated with the SWAT model, climate characteristics on stream flow, slope and rainfall effects on stream flow. ArcGIS used to generate land use and cover maps from Landsat TM and ETM+ acquired, respectively, in 1995, 2005 and 2015. The result of this analysis showed that the cultivated land has expanded during the study period of 1975-2002. Using the three generated land cover maps, three SWAT models set up were run to evaluate the effects of watershed characteristics on the stream flow of the study area. The performance of the SWAT model was evaluated through sensitivity analysis, calibration, and validation. Ten flow parameters were identified to be sensitive for the stream flow of the study area and used for model calibration. The model calibration was carried out using observed stream flow data from 1975 to 1993 and a validation period from 1993 to 2002. Both the calibration and validation results showed good match between measured and simulated stream flow data with the coefficient of determination (R2) of 0.89 and Nash-Sutcliffe efficiency (ENS) of 0.78 for the calibration, and R2 of 0.91 and ENS of 0.88 of the validation period. The result of this analysis indicated that the mean monthly stream flow increased by 21.92m3/s for the wet months while for the dry months decreased by 13.1 m3/s. Generally, the analysis indicated that flow during the wet months has increased, while the flow during the dry months decreased. The SURQ increased, while GWQ decreased from 1975 to 2002 due to the increment of cultivated lands. The model results showed that the stream flow characteristics changed due to the land cover changes during the study period.
Abstract: Evaluating the effects of watershed characteristics have impacted on the stream flow of the watershed by changing the magnitude of surface runoff and ground water flow. This study is mainly focusing the effects of watershed characteristics on the stream flow by changing SURQ and GWQ for the wet months (June, July, August) and dry months (January, F...
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