Large Scale Application of Self-Healing Concrete: Design, Construction, and Testing

Abstract

Materials for Life (M4L) was a 3 year, EPSRC funded, research project carried out by the Universities of Cardiff, Bath and Cambridge to investigate the development of self-healing cementitious construction materials. This paper describes the UK's first site trial of self-healing concrete, which was the culmination of that project. The trial comprised the in-situ construction of five concrete panels using a range of self-healing technologies within the site compound of the A465 Heads of the Valleys Highway upgrading project. Four self-healing techniques were used both individually and in combination with one another. They were: (i) the use of microcapsules developed by the University of Cambridge, in collaboration with industry, containing mineral healing agents, (ii) bacterial healing using the expertise developed at Bath University, (iii) the use of a shape memory polymer (SMP) based system for crack closure and (iv) the delivery of a mineral healing agent through a vascular flow network. Both of the latter, (iii) and (iv), were the product of research undertaken at Cardiff University. This paper describes the design, construction, testing, and monitoring of these trial panels and presents the primary findings of the exercise. The challenges that had to be overcome to incorporate these self-healing techniques into full-scale structures on a live construction site are highlighted, the impact of the different techniques on the behavior of the panels when subject to loading is presented and the ability of the techniques used to heal the cracks that were generated is discussed.

Bacteria-based self-healing concrete: evaluation of full scale demonstrator projects

“…Intermediate results indicate that particularly the sodium silicate-loaded microcapsule based panel show significant crack-width reduction and recovery of permeability [27]. Final results and conclusions on performance of also the other three investigated healing techniques is still pending and currently being monitored under the M4L follow up program 'Resilient Materials for Life (RM4L) program [27,31].…”

“…Although several mechanisms for enhancing the autogenous self-healing capacity of concrete have been investigated under lab conditions only few have been up scaled and applied on demonstrator scale in field trials. Besides the demonstrator projects executed by the Delft research group, as described in this paper, also UK-based research groups participating in the Materials for Life (M4L) research program recently reported on a larger scale outdoors demonstrator project [27,[31][32].…”

“…Monitoring of self-healing performance of the via mechanical loading pre-cracked panels comprising the four incorporated self-healing techniques was done by following crack width-and permeability decrease in time. Crack width variations were monitored by ultrasonic pulse velocimetry and optically by camera and microscopy, and permeability quantified by quantification of in situ air permeability [31]. Intermediate results indicate that particularly the sodium silicate-loaded microcapsule based panel show significant crack-width reduction and recovery of permeability [27].…”

Microcapsule‐Based Visualization Smart Sensors for Damage Detection: Principles and Applications

“…Because of the endless safety accidents caused by concrete fracture, it is crucial to find the fracture of concrete structure in time . Therefore, researchers monitor the concrete cracks by mixing visual microcapsules to concrete or as coatings . In 2017, Hu et al prepared visual coatings embedded with nanocapsules that can self‐report and self‐heal the microcracks via the color change ( Figure ).…”

Development of 3D Printed Networks in Self-Healing Concrete

“…Recently, researchers at Cardiff University [27] have developed a method for creating 2D vascular networks using removal polyurethane tubes to create hollow interconnected channels within cementitious matrices and proven the viability of this healing system in a set of full-scale site trials [28,29]. However, despite these successes, vascular networks are not favoured by contractors because network forming operations are disruptive to the concrete manufacturing and casting process.…”