Tunable chitosan-alginate capsules for a controlled release of crystallisation inhibitors in mortars

Plasters and renders used in historic monuments are vulnerable to degradation caused by salt weathering. Crystallisation inhibitors (molecules/ions that alter salt crystallisation) mixed into mortars have shown promising results in mitigating salt damage by inhibiting salt crystallisation, promoting salt transport to the evaporating surface, and...

Gel-mediated chemo-mechanical control of calcium carbonate crystal formation

The production of synthetic crystals with controlled shapes and properties is an enticing prospect, yet, the production of such materials is an ongoing challenge. Here, we present a strategy for chemo-mechanically directing the growth of crystals with non-equilibrium structures using a custom-designed double-diffusion cell. We combine...

Forming Anisotropic Crystal Composites: Assessing the Mechanical Translation of Gel Network Anisotropy to Calcite Crystal Form

The promise of crystal composites with direction-specific properties is an attractive prospect for diverse applications; however, synthetic strategies for realizing such composites remain elusive. Here, we demonstrate that anisotropic agarose gel networks can mechanically "mold" calcite crystal growth, yielding anisotropically structured,...

Implications of climate change for railway infrastructure

Weather phenomena can result in severe impacts on railway infrastructure. In future, projected changes to the frequency and/or intensity of extreme weather events could change weather–infrastructure risk profiles. Infrastructure owners and operators need to manage current weather impacts and put in place adequate plans to anticipate and adapt...

BioForm – learning at the intersection of science and design

Our future designers have much to learn from the complex and highly functional systems found in nature. Creating design products that are not only human-centred but also in tune with the natural world requires our designers to be exposed to natural phenomena and scientific principles. To provide design students with a starting point, we have...

Optimization of the calcium alginate capsules for self-healing asphalt

It has been demonstrated that calcium alginate capsules can be used as an asphalt healing system by pre-placing rejuvenator (healing agent) into the asphalt mix and releasing the rejuvenator on demand (upon cracking). This healing mechanism relies on the properties of capsules which are determined by the capsule preparation process. In this...

An Improved Test for Generating Rapid, Accurate, and Reliable Crack Permeability Data for Cementitious Materials

Presented is a modified test for generating crack permeability data for cementitious materials. Single-parallel cracks were generated in mortar specimens. The width of the cracks was analysed through stereomicroscope and computer tomography, and the water permeability of the cracks was determined. Reduction factors and crack flow models were...

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...

A cost-effective bacteria-based self-healing cementitious composite for low-temperature marine applications

Bacteria-based self-healing concrete is an innovative self-healing materials approach, whereby bacteria embedded in concrete can form a crack healing mineral precipitate. Structures made from self-healing concrete promise longer service lives, with associated economic benefits [1]. Despite concretes susceptibility to marine-based degradation...

ESEM-BSE coupled with rapid nano-scratching for micro-physicochemical analysis of marine exposed concrete

Ordinary Portland cement (OPC) mortar specimens submerged in sea-water were analysed through environmental scanning electron microscopy (ESEM) in back scattered electron (BSE) mode and nano-scratching. Results from both sets of analysis show the presence of distinct phases associated with aragonite, brucite and cement paste. Phases associated...

Microbially mediated carbonation of marine alkaline minerals: Potential for concrete crack healing

Concrete constructions in the marine environment suffer from chemical attack of sea salts which can induce damage to both the concrete matrix and embedded steel reinforcement. For example, ingress of sulfate and chloride ions can respectively result in detrimental ettringite formation and enhanced corrosion of the steel rebars. The first...

Bacteria-based self-healing concrete for application in the marine environment

Marine concrete structures are exposed to one of the most hostile of natural environments. Many physical and chemical phenomena are usually interdependent and mutually reinforcing in the deterioration of marine exposed concrete: expansion and microcracking due to physical effects increases concrete permeability paving the way for harmful...

Microbially mediated carbonation of marine alkaline minerals: Potential for concrete crack healing

Concrete constructions in the marine environment suffer from chemical attack of sea salts which can induce damage to both the concrete matrix and embedded steel reinforcement. For example, ingress of sulfate and chloride ions can respectively result in detrimental ettringite formation and enhanced corrosion of the steel rebars. The first...

Bacteria-based self-healing concrete for application in the marine environment

Marine concrete structures are exposed to one of the most hostile of natural environments. Many physical and chemical phenomena are usually interdependent and mutually reinforcing in the deterioration of marine exposed concrete: expansion and microcracking due to physical effects increases concrete permeability paving the way for harmful...