The Challenges Related to Interface Bond Characterization of Ultra-High-Performance Concrete With Implications for Bridge Rehabilitation Practices

Abstract

Over the past decade there has been a significant increase in the number of concrete transportation structures reaching the end of their service lives, typically as a result of age and severe degradation. This deterioration is often the result of exposure to aggressive environments and substantial increases in vehicle loading. Rehabilitation is typically the most appropriate solution for these structures because of the high cost of full replacement, resulting in the need for cost-effective and suitable solutions for rehabilitation. Ultra-high-performance concrete (UHPC), one of the more recent advances in construction materials, appears to be a promising material for the repair of concrete structures. The potential benefit of UHPC is primarily derived from its negligible permeability, which prevents water or chemical penetration, and its high mechanical properties, which serve to increase the bearing capacity of the structure. Some of the primary challenges associated with the use of UHPC as a repair material are uncertainty in the bond performance and interaction with the existing substrate material. This paper focuses on the characterization of the interface bond and compatibility between UHPC and normal concrete. The testing program was conducted in the spirit of ASTM because no standard test methods currently exist for UHPC. In addition, a series of numerical models were developed to support the results obtained in the experimental investigations. The results highlight the exceptional performance of the bond, but they also demonstrate a number of challenges with respect to characterizing the bond. Specific challenges included characterization of surface roughness, premature specimen failure, material strength mismatch, and the quality and consistency of the testing methods used.

Multi-Scale Evaluation of the Interphase Zone between the Overlay and Concrete Substrate: Methods and Descriptors

“…Sci. 2017, 7, 893 3 of 11 splitting tensile [34,46,47,[60][61][62] or bi-surface shear strength [63,64]. Although the sand patch test [14,25] and the profilometric method [44,65] are still popular for evaluating the surface morphology of concrete, Tayeh et al [30], Siewczyńska [66], Hoła et al [67] and Sadowski et al [68] successfully used the 3D laser scanning method to evaluate the interphase zone between the overlay and concrete substrate.…”

Numerical Modelling of Concrete-to-UHPC Bond Strength

“…Although the bond strength between normal concrete and UHPC has been experimentally investigated by many researchers while using bi-surface, slant shear, push off, and pull-off tests [39][40][41][42][43][44], there is a gap knowledge that is related to the numerical modelling of the interfacial bond strength for repair design and evaluation. Harris et al, [45] and Azizinamini et al, [46] presented an approach to solve this challenge using simple fix contact surface or tie model between two layers. Such an approach might cause the overestimation of bond strength and global structural performance.…”

Influence of heat treatment regimes on mechanical properties of NSC-UHPC composite members

“…Ultra-high performance concrete usually is described as repair material with extraordinary mechanical properties and enhanced durability (AFGC-SETRA 2013, Harris et al 2015, Muñoz et al 2014. Service life of reinforced concrete structures is limited due to environment that exposes the structure, applied loads and etc., however partial use of UHPC has a potential to enhance exploitation time of reinforced concrete structures.…”

“…The absence of UHPC structural design standards is one of the main problems in order to use this type of material in reliable manner. Despite the fact that standardised bond strength measuring method between NSC and UHPC have not been developed yet, experiments were carried out by other researches (Harris et al 2015, Muñoz et al 2014, Tayeh et al 2013a, Tayeh et al 2013b in order to measure the bond strength between ordinary concrete and UHPC. The existing methods (slant-shear test, push-off test, and splitting tensile test) according to ASTM 882, ASTM C1583, ASTM C496 were used to measure the bond strength, respectively.…”