Influence of PVA and PP fibers addition on the durability and mechanical properties of engineered cementitious composites blended with silica fume and zeolite (original) (raw)
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Journal of Science and Technology in Civil Engineering (STCE) - HUCE
Engineered cementitious composite (ECC) creates many potential civil engineering applications due to its outstanding ultimate tensile strain capacity (normally exceeding 2%) compared to conventional concrete and fiber reinforced concrete. The high tensile ductility of ECC is mainly influenced by fiber characteristics. In this study, the effect of polyvinyl alcohol (PVA) content, i.e. from 2 to 6% by vol. of concrete, on the flexural behavior of ECC with a desired compressive strength of over 60 MPa, in which fly ash and silica fume were selected as supplementary cementitious materials. The experimental results show that the addition of PVA fiber gives little influence on compressive strength but can significantly affect the flexural behavior of ECC. Besides the optimum fiber content, the ratio between the ultimate and first crack strength of ECC was also evaluated.
Effect of pozzolanic industrial wastes on durability of engineered cementitious composites (ECC)
2017
In this research 26 different compositions of an engineered cementitious composite with different percentages of Fly ash and Silica fume, as two pozzolanic industrial waste and by-product, were mixed. The effect of different percentage of the pozzolans on durability of ECC was studied. To evaluate the durability of the material, two tests, namely water absorption by immersion and water absorption by capillary, were performed. The results from both tests demonstrated the same trend regarding the influence of the wastes on durability. In other words, by increasing the amount of pozzolans, the water absorption after immersion and boiling, decreased more than 50% besides the significant reduction in the rate of absorption by capillary (sorptivity). The results also indicated that silica fume has a higher influence on the water-absorption reduction compared to fly ash however, in the case of absence of silica fume, fly ash plays a significant role on the improvement of durability of the ...
2016
This paper presents the outcome of a study conducted to exhibit the effect of micro-silica sand and mortar sand on fresh, mechanical and durability properties of Engineered Cementitious Composites (ECCs). ECC is a ductile concrete characterized by strain hardening and multiple-cracking behavior under tension and shear. This study used locally available aggregates instead of standard micro-silica sand to produce cost-effective, sustainable and green ECC mixtures to be used for construction applications. ECCs prepared by both types of sands exhibited almost similar behaviour in terms of fresh, mechanical and durability properties which indicated the viability of producing ECC mixtures with mortar sand. In addition, the behaviour of a standard ECC can still be achieved when producing ECCs made of high volume fly ash (up to 70% cement replacement) along with local mortar sand. By employing results of this research, correlations were derived between mechanical and durability properties.
International Journal of Engineering Research and Technology (IJERT), 2019
https://www.ijert.org/Effect-of-Polyvinyl-Alcohol-and-Steel-Fiber-on-Durability-Properties-of-Cementitious-Composites https://www.ijert.org/research/effect-of-polyvinyl-alcohol-and-steel-fiber-on-durability-properties-of-cementitious-composites-IJERTCONV7IS02006.pdf Traditional concrete is considered as brittle and rigid, also conventional concrete is not highly durable. The lack of durability of concrete is on account of the presence of calcium hydroxide and the transition zone, which represents the interfacial region between the particles of coarse aggregate and the hardened cement paste. Steel bars are used in concrete members to keep cracks as small as possible. But they are not small enough to heal, so water and deicing salts can penetrate to the steel, causing corrosion that further weakens the structure by affecting the durability. This result is development of engineered cementitious composites. The purpose of this project is to study the Durability properties of Engineered Cementitious Composites. To verify that, in this project Steel fiber and polyvinyl alcohol fiber with various proportions of mineral admixtures such as rice husk ash and silica fume has been used in ECC to study its structural performance and durable properties.
Cement & Concrete Composites, 2006
The influence of the matrix formulation and different amounts of synthetic fiber on physical and mechanical performance of asbestos free fiber cement was evaluated. Polyvinyl alcohol (PVA) fiber was tested as reinforcement in combination with mechanical and kraft cellulose pulps. Silica-fume, metakaolin and fly ash were used as pozzolanic additions in proportions up to $14% by mass in combination with ordinary Portland cement and carbonatic filler. Bulk densities of composites varied from 1.5 to 1.7 g/cm 3 . Synthetic fiber contents higher than 2% by mass (from 4% to 5% by volume of the composite) were unable to promote any further improvement in the mechanical performance of the composites at the age of 28 days. Formulations with silica fume showed better strength performance for the composites after accelerated aging test. The toughness measurements of composites after exposition to soak and dry cycles also showed that silica fume seems to prevent cellulose fiber degradation.
Materials
This study investigates the mechanical and durability properties of fly ash-based engineered cementitious composites (ECC). The effect of various mineral additions, such as wheat husk ash (WHA), rice husk ash (RHA), glass powder (GP), and fibrillated polypropylene (PP) fibers, on mechanical performance, water absorption, and porosity was investigated. Furthermore, the durability of ECC specimens was assessed in terms of sorptivity, acid/sulfate attacks, electric resistivity (ER), rapid chloride penetration (RCPT), and ultrasonic pulse velocity (UPV). The results revealed higher mechanical strength, UPV, and ER values for RHA-based ECC. After 180 days of immersion in acid and sulfate solutions, RHA-based ECC showed a lower loss in compressive strength (23.21% and 1.07% in HCl and Na2SO4, respectively) relative to the control mix (44% and 7% in HCl and Na2SO4, respectively). Moreover, analytical characterizations such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scan...
For each ton of Cement produced, one ton of CO 2 , a greenhouse gas, is released into the atmosphere. Worldwide, the Cement industry produced about 1.4 billion tons in 1995, which caused the emission of as much CO 2 gas as 300 million automobiles. Our industry has a responsibility and societal duty to make a contribution towards taking the steps necessary to achieve sustainable development. A scientific approach towards conserving natural resources involves increasing durability of structures, because more durable structures need to be replaced less frequently. Such increased durability can be achieved by choosing appropriate mix designs and selecting suitable Aggregates and admixtures. Development of Engineered Cementitious Composite (ECC) materials using High volume of Fly Ash and Polyvinyl Alcohol (PVA) fibers will produce the most promising construction materials with High durability. This Paper focuses on Development and study of Engineered Cementitious Composites using High Volume Fly Ash and Polyvinyl Alcohol Fiber, the use of which will increase the durability and hence lead to the Sustainable Development in Construction Industry.
Evaluation of Engineering Cementitious Composites (ECC) With Different Percentage of Fibers
Concrete is good in compression but if any type of strain applied to it, it starts to fail. Where the steel is good tension. It can bear the deflection up to its elastic limits. This project is based on behavior of engineered cementitious composited (ECC) when it is replaced with the different amount of Polyvinyl Alcohol (PVA) Fibers. As for research, PVA fibers is used with cementitious up to 2% to evaluate the optimum amount of fiber on which we can find the maximum compressive, tensile and flexural strength. PVA is basically an adhesive which is used to formulate glue [1]. Generally due to excessive loading, cracks develops which concludes to successive damage to the structural component. In research plasticizer is used to increase workability. With the help of optimum amount of PVA fibers, it can limit the crack widths up to 60µm to 100µm [2]. Also can be used to reduce resources and funds for rehabilitation of structure. At the starting this fiber concrete can be double the cost as compare to conventional concrete but as it can amplify the duration of structure, it will be less costlier than the conventional concrete.
The Effect of Nylon Fibers on Mechanical Properties of Engineered Cementitious Composites (ECCs)
The advantages of staple fibers as reinforcement in cement based composites are well known. The interaction between fiber and cementitious matrix is effective in mechanical properties of composites. Engineered cementitious composite (ECC), is a new type of high performance fiber reinforced cementitious composites with high ductility. It is used for seismic applications, impact and blast resistant structures. The flexural strength of these composites is very high. This is why they were named as bendable concrete. Polyvinyl alcohol fibers are introduced as the best reinforcement for ECCs, but unfortunately they are not produced in our country. In this paper, a commercial ECC mix design is used and the feasibility of application of low modulus polymeric fibers instead of PVA fibers is investigated. For this reason, the three point bending tests are carried out on ECC sheets containing 2% by volume of nylon 66 fibers with two different lengths. Results show that the flexural toughness of ECC specimens with 12mm nylon 66 fibers is increased more than 130 times in comparison to the control specimen. Furthermore, the flexural behavior of ECC samples is improved with increase in fiber length.
A disadvantage of conventional concrete is its low flexural strength and ductility in tension. Cracks form when the tensile strength of conventional concrete, which is limited, is exceeded due to various actions (loads, restrained shrinkage, temperature variation, chemical reactivity) accentuating the effects of carbonation and chloride-induced corrosion of concrete and reinforcement, thereby compromising the residual service life and strength of concrete members. Addition of fibers to enhance the flexural capacity of structural materials through crack control is an ancient idea that is now spearheading novel developments in the area of high-performance cementitious materials. Currently, the state of the art is focused on the use of synthetic fibers in self-consolidating, fine-aggregate cementitious mixes that demonstrate strain hardening properties in tension, outstanding crack control and improved durability performance. This paper deals with experimental characterization of the performance of a material of this class, reinforced with PVA fibers (polyvinyl alcohol with original hydrophilic surface properties). Parameter of study is the length of the fibers as well as the fiber surface properties which are chemically modified through pertinent surfactants. The parametric study compares the mechanical response of FRC to that of plain (unreinforced) cementitious material of the same composition, through tests of material samples in uniaxial compression, extension, splitting and flexure.