Multi-Scale Characterization of Corrosion Initiation of Preloaded Hybrid Fiber-Reinforced Concrete Composites

2016 ◽  
Vol 711 ◽  
pp. 195-202
Author(s):  
Wilson Nguyen ◽  
Jacob F. Duncan ◽  
Paulo J.M. Monteiro ◽  
Claudia P. Ostertag
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Damage ◽  
Fiber Reinforced Concrete ◽  
Matrix Cracking ◽  
Fiber Reinforced ◽  
Micro Computed Tomography ◽  
Hybrid Fiber ◽  
Multi Scale ◽  
Corrosion Initiation ◽  
Scale Characterization

Many reinforced concrete structures susceptible to corrosion damage are subjected to externally applied loads, causing cracking. These cracks increase the permeability of the material, accelerating the ingress of corrosion-inducing deleterious agents. In this paper, the effect of multiple microcracking and macrocrack formation on corrosion initiation was investigated. A hybrid fiber-reinforced concrete (HyFRC), which forms ductile, distributed microcracking prior to dominant crack localization due to multiple tiers of fiber reinforcement, is being studied for its performance against corrosion damage. The effect of matrix cracking on corrosion initiation was studied with beam specimens preloaded in flexure prior to long-term corrosion exposure. Reinforced HyFRC composites were found to have a delayed corrosion initiation response due to reductions in crack widths and suppression of splitting cracks, compared to conventional reinforced concrete. The influence of microcracks on corrosion is studied using X-ray micro-computed tomography (μCT) on reinforced fiber-reinforced cementitious composites and reinforced mortar preloaded in tension.

A novel multi-scale model for predicting the thermal damage of hybrid fiber-reinforced concrete

2019 ◽  
Vol 29 (1) ◽  
pp. 19-44 ◽  
Author(s):  
Yao Zhang ◽  
J Woody Ju ◽  
Hehua Zhu ◽  
Zhiguo Yan
Keyword(s):  
Reinforced Concrete ◽  
Cement Paste ◽  
Thermal Damage ◽  
Fiber Reinforced Concrete ◽  
Scale Model ◽  
Fiber Reinforced ◽  
Interfacial Damage ◽  
Hybrid Fiber ◽  
Multi Scale ◽  
Damage Degree

A multi-scale micromechanical model is proposed to predict the damage degree of hybrid fiber-reinforced concrete under or after high temperatures. The thermal degradation of hybrid fiber-reinforced concrete is generally composed of the damage of the cement paste caused by thermal decomposition and thermal incompatibility, the deterioration of aggregates and fibers, and the interfacial damage between aggregates and the matrix. In this multi-scale model, four levels of hybrid fiber-reinforced concrete structures are considered when the thermal damage degree is derived; namely, the equivalent calcium silicate hydrate (C–S–H) product level, the cement paste level, the concrete level, and the hybrid fiber-reinforced concrete level. At the cement paste level, thermal decompositions of C–S–H product and calcium hydroxide are taken into account. In addition, a dimensionless parameter of the crack density is introduced to represent the thermal cracking of the matrix. At the concrete level, the interfacial damage of aggregates is simulated by a spring–interface model, in which the interfacial parameters are assumed to be functions of temperature. Moreover, at the cement paste level and the hybrid fiber-reinforced concrete level, a sub-stepping homogenization method is proposed to determine the effective properties. Comparisons between previously published experimental data and predictions and discussions illustrate the feasibility of the proposed multi-scale model in predicting thermal damage of concrete and hybrid fiber-reinforced concrete.

Crack Resistance and Permeability of Hybrid Fiber Reinforced Concrete Application in Understructure Work

2013 ◽  
Vol 438-439 ◽  
pp. 257-261
Author(s):  
Shu Jin Li ◽  
Hong Ping Qian
Keyword(s):  
Reinforced Concrete ◽  
Cellulose Fiber ◽  
Fiber Reinforced Concrete ◽  
Matrix Cracking ◽  
Test Results ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Hybrid Fibers ◽  
Cracking Performance ◽  
Pva Fiber

An investigation of early anti-cracking performance and permeability of hybrid cellulose fiber and PVA fiber reinforced concrete is presented in this article. The test results show that, both cellulose fiber and PVA fiber effectively improve the splitting tensile strength. The early anti-cracking performance of concrete is obviously improved by PVA and cellulose hybrid fibers, and there exists the synergistic effect for restrain matrix cracking with hybrid fibers. Based on the practical application of a subway station project during two years, result shows the underground concrete wallboard containing hybrid fibers does not produce obvious cracks and leakage problem.

scholarly journals A review on hybrid fiber reinforced concrete pavements technology

2021 ◽  
Vol 1895 (1) ◽  
pp. 012053
Author(s):  
Hadeel M. Shakir ◽  
Ahmed Farhan Al-Tameemi ◽  
Adel A. Al-Azzawi
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Concrete Pavements ◽  
Fiber Reinforced ◽  
Hybrid Fiber

Experimental Study of Bending Toughness on Hybrid Fiber Reinforced Concrete

2013 ◽  
Vol 327 ◽  
pp. 201-204
Author(s):  
Jin Song Shi ◽  
Bo Yuan ◽  
Da Zhang Wang ◽  
Zhe An Lu
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Toughness Index ◽  
The Difference ◽  
Loading Methods ◽  
Index Value

In order to investigate the difference of current toughness index standards for fiber reinforced concrete, two main groups of specimens were made to take bending toughness test with the requirements of corresponded standards, loading methods and loading speeds, which are ASTM C1018 in America, ACI 544 and JSCE G552 in Japan. United with software Origin, the load-deflection curves gathered from bending test was calculated with relative standards. The results show that the calculated toughness index value with ASTM C1018-98 in America is more accurate with three grades but the requested deflection of testing is much longer than others while ACI 544 and JSCE G552 in Japan are quite the contrary.

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