Bendable Concrete for Engineered Cementitious - myassignmenthelp

Question: Discuss about theBendable Concrete for Engineered Cementitious Concrete. Answer: Introduction Engineered Cementitious Concrete is also the name of bendable concrete which is a mortar easily moulded having reinforced composite using chosen random fibres, mostly polymer fibres. Past research on ECC has mentioned the feature of conventional concrete being of low capacity in a strain of around 0.1%. This feature, therefore, makes it rigid and brittle. The missing bendability feature hence makes it susceptible to failure when strain is loaded. This was what made the basis for developing bendable concrete. Bendable concrete as its ingredients similar to conventional concrete with an added high-range agent that reduces water imparting good workability. The major components used in making ECC are; cement, fin aggregate and fibre. Other added materials include silica fume, fly ash, blast furnace slag which only increases the content of paste. ECC has the feature of using low amounts, relatively 2% volume lower with fibres that are short and discontinuous. The various ECC ingredients work in unison in sharing the applied load making It 50 times flexible than conventional concrete and lighter o about 40%. Its absorbing properties of energy also make it suitable for use in areas proven to seismic zones. This paper reviews the various literature on ECC and makes it conclusion on them. Literature Review (Alan, David, David, 2016) has performed a parametric study of ECC to find that the flexural strength, compressive strength and features of deflection of a number of fibre types for different beam depths. There is a compared study on fresh hardened concrete properties. The result is that steel fibre ECC has 5% more compressive strength than normal concrete while the use of hybrid fibres and PVA makes them 20% and 15% more than normal concrete. The ECC density is lower to 20% than normal concrete. The deflection and flexural strength are related inversely to the specimens cross-sectional area. As the fibre percentage increases, the energy absorption property also increases to 20% with an increase of specimen cross-section, an evaluated 10% energy absorption is observed. (Blaine, 2017) had an experiment on improving the distribution of fibre by changing the mixing sequence. Standard mixing sequence entails addition of fibre to liquid and solid materials for mixing. The unwanted plastic viscosity before the inclusion of fibre may lead to poor distribution of fibre rusting to unwanted hardened properties. When the sequence of mixing is adjusted, solid materials are mixed with materials that are liquid in two steps with fibre addition in these two steps. This study investigated the use of various mixing sequences with the experimental results of analyzed fibre distribution and tensile uniaxial test compared. It was concluded that adjustment in mixing sequence increased the capacity of tensile strain as well as it improving the tensile strength with better distribution of fire enhanced. (Edward, 2008) studied an experiment that seek to find out the effect of great micro-PVA and fly ash fibres on the resistance of cyclic freeze-thaw and the ECC microstructure. Various ECC mixtures were prepared with two different ratios of FA to cement. The sued ratios were 112 and 2.2 weights, with constant materials in water-cementitious matter. Of 0.27. The tests involved measuring the properties of residual mechanics, velocity of ultrasonic pulse and loss of mass. Outcome of the experiments confirmed mixtures of ECC having high FA volumes being more durable with indication of 2% more capacity of tensile strain after 300 thawing and freezing cycles. Hence the micro-PVA fibre improved the resistance to first. Outcomes from free-thaw tests showed the effect of reducing mechanical properties and physical properties with an increase in freeze-thaw cycle number was relatively more in ECC mix of 2.2 FA/C ratio than ECC mix of 1.2 FA/C ratio. (Jacques Franois, 2013) Performed an experiment that evaluated the study of feasibility with the use of ultra-ductile ECC for the purpose of enhancing performance of connection of type-2 interior beam-columns. The test of these interior connections at zone 3 with regards to uniform building code having great seismic with loading cycle that is reversed for excited seismic simulation. The results of the tests showed that these used ECC material in the plastic zone connections that replaced concrete as well as partial transverse reinforcement emplacement have enhanced resistance on the joint shear. Also, energy absorption has been enhanced and response in cracking. It was found that the ECC-enhanced specimens possessed higher capacity compared to the control experiment. The increased dissipated energy amount was gotten from using ECC having a range of 11-20%. These results indicated reasonable factor of safety against the stress-induced joint shear failure under loading cycle. (Konstantin Surendra, 2015) had an experiment on the study of ECC mechanical properties gotten form admixtures of high volume which include fly ash, silica fume and slag. The ratio of water-binder materials were kept to 0.25 for these mixtures. The result from the experiment showed that compressive strength was inversely related to deflection, fracture energy and toughness index. The EC ductility would have an obvious improvement in reducing the high volume slag and fly ash cement replacement. However, the compressive strength of the ECC slag and fly ash reduced to 14% and 40% respectively. The ternary binder material system having 70% cement, combined to slag and fly ash only keeps the excellent ECC ductility but also provides improved matrix strength. (Recep, Hediye,, Yusuf, 2017) performed an experiment on 36 ECC mixtures that were different for evaluation of combined effects of the factors that follow regarding rheological and workability properties: san-binder, water-binder, maximum aggregate size and super plasticizer-binder. The used evaluation was rational viscometer, March cone and mini-slump cone for the determination of rheological and workability properties. Results from the experiment indicated that s/b, w/b and SP/b affected the workability and rheological properties. Studies the aggregate size found this to not affect the rheological and workability properties significantly. Conclusion From the above-reviewed literature, the remarks that follow made an admirable conclusion that; As the fibre in ECC increases, the energy absorption property increase to 20% The ECC specimen have higher capacity when compared to normal concrete. The water-cementitious material ratio of 0.22 to 0.27 has the best outcome. The ECC compressive strength having steel fibres is 5% more compared to normal concrete and used hybrid fibres and PVA have 20% and 15% less strength. 4 FA/C ratio provides better residual tensile ductility after exposure to sub-elevated temperatures. However, gaps such as fly ash multi-cracking capability need to be further researched on to make an evaluation on the cracking under extreme temperature. It is therefore proven that researching on bendable concrete would increase its advantages making better building materials for future structures(Viktor, Volker, Petr, 2017). References Alan, J., David, A., David, P. (2016). Architectural Drafting and Design. Tyre: Cengage Learning. Blaine, B. (2017). Transmaterial Next: A Catalog of Materials that Redefine Our Future. Sidon: Princeton Architectural Press. Edward, G. (2008). Concrete Construction Engineering Handbook. Tyre: CRC Press. Jacques, R., Franois, T. (2013). Designing and Building with UHPFRC. Sidon: John Wiley Sons. Konstantin, S., Surendra, P. (2015). Nanotechnology in Construction: Proceedings of NICOM5. Tripoli: Springer. Recep, H., H. K., Yusuf, F. (2017). International Advanced Researches Engineering Congress 2017 Proceeding Book. Beirut: INTERNATIONAL WORKSHOPS. Viktor, M., Volker, S., Petr, K. (2017). Strain-Hardening Cement-Based Composites: SHCC4. Beirut: Springer.