Influence of steel fiber corrosion on tensile properties and cracking mechanism of ultra-high performance concrete in an electrochemical corrosion environment

107

This review article proposes the identification and basic concepts of materials that might be used for the production of high-performance concrete (HPC) and ultra-high-performance concrete (UHPC). Although other reviews have addressed this topic, the present work differs by presenting relevant aspects on possible materials applied in the production of HPC and UHPC. The main innovation of this review article is to identify the perspectives for new materials that can be considered in the production of novel special concretes. After consulting different bibliographic databases, some information related to ordinary Portland cement (OPC), mineral additions, aggregates, and chemical additives used for the production of HPC and UHPC were highlighted. Relevant information on the application of synthetic and natural fibers is also highlighted in association with a cement matrix of HPC and UHPC, forming composites with properties superior to conventional concrete used in civil construction. The article also presents some relevant characteristics for the application of HPC and UHPC produced with alkali-activated cement, an alternative binder to OPC produced through the reaction between two essential components: precursors and activators. Some information about the main types of precursors, subdivided into materials rich in aluminosilicates and rich in calcium, were also highlighted. Finally, suggestions for future work related to the application of HPC and UHPC are highlighted, guiding future research on this topic.

Section: Hpc and Uhpc Containing Fibers: Composite Materialsmentioning

confidence: 99%

Section: Hpc and Uhpc Containing Fibers: Composite Materialsmentioning

confidence: 99%

Materials for Production of High and Ultra-High Performance Concrete: Review and Perspective of Possible Novel Materials

Marvila¹,

Azevedo²,

Matos

et al. 2021

107

“…Existing methods to improve the tensile properties of UHPC include increasing the fiber content, increasing the fiber aspect ratio, using anisotropic fibers, and modifying the fiber surface [ 2 , 5 , 6 , 7 , 8 , 9 , 10 ]. Most of these methods improve the tensile mechanical properties of UHPC by adjusting the fiber parameters, which has some shortcomings.…”

Section: Introductionmentioning

confidence: 99%

Enhancing UHPC Tensile Performance Using Polystyrene Beads: Significant Improvements and Mechanisms

Guo,

Chen,

Chen

et al. 2024

Self Cite

This study investigates utilizing spherical polystyrene (PS) beads as artificial flaws to improve ultrahigh-performance concrete (UHPC) tensile performance using a uniaxial tensile test and explains the corresponding mechanisms by analyzing the internal material structure of UHPC specimens with X-ray CT scanning. With a hooked steel fiber volume fraction of 2%, three PS bead dosages were employed to study tensile behavior changes in dog-bone UHPC specimens. A 33.4% increase in ultimate tensile strength and 174.8% increase in ultimate tensile strain were recorded after adding PS beads with a volume fraction of 2%. To explain this improvement, X-ray CT scanning was utilized to investigate the post-test internal material structures of the dog-bone specimens. AVIZO software was used to analyze the CT information. The CT results revealed that PS beads could not only serve as the artificial flaws to increase the cracking behavior of the matrix of UHPC but also significantly optimize the fiber orientation. The PS beads could serve as stirrers during the mixing process to distribute fiber more uniformly. The test results indicate a relationship between fiber orientation and UHPC tensile strength.

“…It has been reported that steel fibers, when added to concrete, can increase its porosity, allowing aggressive ions to enter deep into the concrete [33], which can further aggravate the corrosion problem. With the increase in steel fiber corrosion, a reduction in its ability to control cracks and a rapid increase in crack width has been reported [34]. Many research studies have been carried out on the durability of steel-fiber-reinforced concrete, and it is concluded that steel fiber bridging cracks wider than 0.5 mm have a significant risk of corrosion [31,35,36].…”

Section: Introductionmentioning

confidence: 99%

Durability Properties of Macro-Polypropylene Fiber Reinforced Self-Compacting Concrete

Chen,

Waheed,

Iqbal

et al. 2024

Concrete is one of the most commonly used construction materials; however, its durability plays a pivotal role in areas where the concrete is exposed to severe environmental conditions, which initiate cracks inside and disintegrate it. Randomly distributed short fibers arrest the initiation and propagation of micro-cracks in the concrete and maintain its integrity. Traditional polypropylene fibers are thin and encounter the problem of balling effects during concrete mixing, leading to uneven fiber distribution. Thus, a new polypropylene fiber is developed by gluing thin ones together, forming macro-polypropylene fibers. Thus, different amounts of fibers, 0–1.5% v/f with an increment of 0.5% v/f, are used in different grades of concrete to study their impact on durability properties, including resistance to freezing and thawing cycles, sulfate, and acid attacks. A total of 432 cube samples were tested at 28, 56, and 92 days. The results reveal that the maximum durability, in terms of compressive strength loss, is noted with a fiber content of 1% with improved resistance of 72%, 54%, and 24% against freeze–thaw cycles, sulfate attack, and hydrochloric acid attack, respectively, at 92 days. Thus, the resulting fiber-reinforced concrete may be effective in areas where these extreme exposure conditions are expected.