Papers by Keyword: ECC

Abstract: To explore the influence of different factors on the shear resistance of the fiber-reinforced Engineered Cementitious Composite (ECC) and ordinary concrete interface, the influence rule of rib width, rib height, and planting bars ratio on the interface shear strength of steel fiber-reinforced ECC and ordinary concrete was investigated by orthogonal experimental design. The experimental results show the rib width is the most important factor affecting the shear strength of the interface, and the ratio of planting bars minimally influences the shear strength of the interface. The order of main influence factors of shear resistance of interface can be arranged as follows: rib width→rib height→planting bars ratio. Experimental process and load-displacement curve show the failure of the double-sided shear specimen with ribs or planting bars has certain plastic failure characteristics, which extends the failure time of the specimens.

Abstract: This research aims to investigate the mechanical properties of engineered cementitious composites including compressive strength, splitting tensile strength, modulus of rupture, and load-deflection behavior. In addition, the abrasion test of concrete under water, which is recommended by ASTM C1138, was carried out and its results were compared with the splitting and modulus of rupture test results. Untreated low-cost polyvinyl fibers were used with different volume fractions of 0.5, 1.0, 1.5, and 2.0%. All tests were carried out at the standard age of 28 days. The experimental results showed that the use of 2% of low cost polyvinyl fibers with the engineered cementitious composites led to the increase of the splitting tensile strength and the modulus of rupture by 134% and 287%, respectively, compared to specimens incorporating no fibers. The results showed also that the deflection and the ultimate failure load increases as the fiber content increase.

Abstract: Corrosion of short steel fibers is one of the limit factors for using cement based UHPC material like an architectural concrete. The steel fibers corrosion is undesirable effect. PVA fibers and TRC reinforcement are nowadays used for facade elements. Structural elements reinforced by non-conventional reinforcement have lower tensile strength, also modulus of rupture is lower, due to low tensile strengths and deformation modulus of PVA and TRC. The tensile strength is determined by properties of mixture design. The potential of functionally layered thin slabs consist on the high ductility and tensile strength of UHPC matrix reinforced by short steel fibers. The load bearing part of functionally layered slabs is made by UHPC reinforced by steel fibers and the covering part is made by ECC reinforced by PVA fibers. Ductile and durable elements should be prepared by acceptable ratio between load bearing part and covering part of functionally layered thin slab. Functionally layered slabs should be used for architectural facade elements.

Abstract: Polyvinyl alcohol (PVA) fiber reinforced cementitious material (called PVA-ECC) has been intensively studied as a promising alternative to ordinary cement materials. While PVA-ECC has high stain capacity and ductility, its extreme high cost mainly caused by the high unit cost of used Japanese fiber has hindered its application in China. In order to reduce the cost of PVA-ECC, one type of inexpensive PVA fiber produced in China was used to develop a ductile ECC with deflection hardening and multiple cracking behaviors in this research. Compressive strength test, four-point bending test and uniaxial tension test were conducted to investigate the mechanical properties of the newly developed composites. The results show that ECC made with domestic ingredients exhibits large deformation and multiple cracking, revealing that it is feasible to produce low cost ECC material employing local PVA fibers.

Abstract: An increasing number of steel orthotropic bridge deck require repair due to fatigue cracking. For the rib to deckplate joint, a possible solution is to reinforce the fatigue prone deck plate by replacing the asphalt wearing surface with a reinforced high strength concrete overlay. However, this process has been proven very difficult to execute and consequently has some issues regarding durability. This paper reports on high performance fiber reinforced cement based overlay solutions with gritted epoxy interlayer for a typical orthotropic deck with inadequate plate dimensions. Material characterization of three mix designs includes determination of compressive and tensile strength, and post crack behavior by CMOD registration from 3PBT. Furthermore, the steel-concrete composite action in the positive and negative bending moment zone is investigated experimentally. The test results give insight into the concrete behavior, the steel-epoxy-concrete interaction, and are used as input for a 3D finite element model of the reinforced deck under fatigue loading. The results indicate that fiber reinforced cement based overlay solutions may be a viable option for orthotropic decks with inadequate deck plate thicknesses

Abstract: Engineered Cementitious Composite (ECC) is a material with high ductility, tensile strength and self-healing more than the standard concrete. Applications of ECC are beneficial due to its long life cycle, high strength, low cost in the long-term, low maintenance and environmentally friendly nature. Properties and hardened behavior of ECC highlights that ECC has a tight crack width development, which increases its ability to resist long-term effects of hot, frost and humid weather. Additionally, it results low water permeability coefficient and high steel corrosion resistance compared to other common alternative materials. One of the promising areas of application for ECC is in highway structures, especially highway bridges. Highway structures suffer constantly from adverse environmental loads and often require frequent repairing or replacing due to cracks; expansion; water and chlorides effects which cause steel corrosion or the slope between the pavement, slab and the support at the end of a bridge. Detailed review on different properties and characteristics of ECC and the current applications of ECC clearly highlights the motivation to enhance the use of ECC for bridge construction. In addition, ECC can be introduced in jointless bridges by putting an ECC link slab instead of the expandable mechanical joint.

Abstract: Upcoming infrastructure and maintenance focuses on sustainable infrastructure. To solve this, certain cement – based materials are developed. Engineered Cementitious composite (ECC) has been developed as an improved version of Fiber Reinforced Cement. The most outstanding properties of ECC are its high tensile ductility and fine multiple cracking. It is basically a composite similar to mortar added with fine fibers such as steel fibers and polymer fibers. A composite with high ductility is made retaining the original properties of normal concrete leads to a sustainable and serviceable construction. The materials used for ECC are cement, fly ash, fine cement, admixtures, fibers and water. Sand used in this mix is very fine which have 0.1mm dia. The fibers used in this study are polypropylene and steel fiber. Fibers are added at the rate of 0.5%, 1%, 1.5%, 2% volume of cement. This paper deals with the experimental investigation of compressive strength, tensile strength, and flexural strength of ECC made with polypropylene and a mixed proportion of polypropylene with steel fiber with different volume percentages i.e., 2%, 1.5%, 1% and 0.5%. It is observed that addition of fibers increased the ductile behavior. ECC with polypropylene fiber had shown significant improvement in tensile and flexural strength while ECC with hybrid fiber had given appreciable compressive strength development. These efforts will focus on the development of sustainable green material, which reduces the negative impact of existing concrete on the environment. The potential application of ECC to achieve structural sustainability has been observed from the results obtained.

Abstract: This paper is focused on a mechanical properties of fine-grained cement based composite materials reinforced by short PVA fibers. Cementitious materials are characterized by their fragile matrix. Reinforcing by fibers (e.g. steel fibers, PVA fibers, PP fibers, glass fibers) increase the tensile strength. The behavior of the elements after developing and spreading of micro cracks under load should be described as a strain-softening, strain-hardening, etc. The multiple cracking under load is typical deformations of composite materials reinforced by short PVA fibers, that is worldwide known as a ECC.

Abstract: This paper presents a series of experimental studies on the behaviour of engineered cementitious composites (ECC) under quasi-static and high strain rate loads. Potential enhancement of ECC to the resistance and ductility of structural members was evaluated under column removal scenarios and impact loading conditions. Besides, dynamic increase factors for compressive strength and critical strain were derived according to experimental results under high strain rates. Finally, conclusions and recommendations were made in accordance with the use of these materials for different structural performances.

Abstract: This article prepared a new type PVA fiber with large diameter by plasticizing melt spinning method, which instead of traditional wet-spinning or gel-spinning method. The mechanical properties and microstructure of fiber were characterized by tensile instrument respectively and SEM. Then, the PVA fiber was used in cementitious composites after surface sizing. The test result shown that: the melt-spinning PVA fiber could achieve stress-strain hardening in ECC system, and appeared multi-cracking phenomenon, the flexural deflection and strength is not worse than the Japan Kurary PVA fiber. Finally, the PVA has an advantage in price.