Report of RILEM TC 281-CCC: outcomes of a round robin on the resistance to accelerated carbonation of Portland, Portland-fly ash and blast-furnace blended cements

Many (inter)national standards exist to evaluate the resistance of mortar and concrete to carbonation. When a carbonation coefficient is used for performance comparison of mixtures or service life prediction, the applied boundary conditions during curing, preconditioning and carbonation play a crucial role, specifically when using latent...

Self-Healing Materials are Coming of Age

Volume fraction, thickness, and permeability of the sealing layer in microbial self-healing concrete containing biogranules

Autonomous repair systems in construction materials have become a promising alternative to current unsustainable and labor-intensive maintenance methods. Biomineralization is a popular route that has been applied to enhance the self-healing capacity of concrete. Various axenic microbial cultures were coupled with protective carriers, and their...

Design of polymeric capsules for autonomous healing of cracks in cementitious materials

Now, most of the capsules used to contain polymeric healing agents in self-healing concrete, are made of glass. However, glass capsules cannot be mixed in concrete and are therefore placed manually into the moulds during concrete casting in laboratory tests. This represents a major drawback for an eventual industrialisation. In this study,...

Non-destructive testing techniques for the observation of healing effects in cementitious materials: An introduction

To develop an appropriate method of self-healing for cementitious materials including the right composition and amount of suitable healing agents it is required to investigate the healing efficiency for certain material mixtures. While some researchers evaluate the regain in compressive strength by means of destructive load tests, this method is...

Microfibres and hydrogels to promote autogenous healing in cementitious materials

Cementitious materials are sensitive to crack formation and it would be beneficial if the material could stop the crack propagation, repair the damage and reach again the original liquid-tightness and/or strength. Therefore, a cementitious material with synthetic microfibres and superabsorbent polymers (SAPs) is proposed. Upon crack formation,...

Healcon: Self-healing concrete to create durable and sustainable concrete structures

Within the theme ‘Self-healing materials for prolonged lifetime’ (NMP.2012.2.1-3) of the Seventh Framework Programme, self-healing concrete is an important topic. The project HEALCON, which deals with self-healing concrete to create durable and sustainable concrete structures, is funded by EU-FP7 and started in January 2013. The coordinator of...

Hydrogel encapsulated bacterial spores for self-healing concrete: Proof of concept

Self-healing concrete is regarded as a promising solution to reduce the high maintenance and repair cost of concrete infrastructure. Due to the limited autogenous healing capacity of concrete as such, additives are needed to enhance its self-healing properties. Among various strategies, microbial-based self-healing has gained increasing...

Investigation of the fracture cracking behavior of self-healing systems by use of optical and acoustic experimental methods

Nowadays the self-healing process efficiency in loaded structural materials is evaluated by studying the damage mechanisms. Based on fracture mechanics theories, the resistance to damage and the cracking recovery can be an indication of healing performance. Experimentally, the cracking behavior is quantified by measuring the fracture energy of...

ICSHM 2013: Proceedings of the 4th International Conference on Self-Healing Materials, Ghent, Belgium, 16-20 June 2013

Symposium organised by Ghent University, Department of Structural Engineering and Delft University of Technology, Aerospace Structures & Materials. Materials play an extremely important role in our lives. These materials may be of a very different nature ranging from metals over concrete to polymers and composite materials. They all have in...

Most recent advances in the field of self-healing cementitious materials

While the Japanese researchers Ohama et al. [1] already mentioned in 1992 that a self-healing effect was noticed when polymer-modified concrete without hardener was made, the real pioneer in the research on self-healing concrete is Carolyn Dry from Illinois. The first time she proposed the use of encapsulated polymers to obtain self-healing...

SHE: The Flemish program on engineerd self-healing materials

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Resistance of cracked concrete healed by means of polyurethane against chloride penetration

A lot of damage is reported for constructions in marine environments. Marine environments are very aggressive, because of the high chloride concentration in sea water. Chlorides affect durability by initiating corrosion of the reinforcement steel. When cracks appear in the concrete structures, chlorides will penetrate faster and will initiate...

Self-healing of thermal cracks in sandwich panels

Sandwich panels are prefabricated, insulated concrete wall elements, which are sensitive to thermal cracking due to their composition (concrete outer cladding – insulation – concrete inner cladding). During hot days, the temperature of the outer concrete layer can rise up to ~ 60°C and the temperature difference between inner and outer layer...