Combinatory approach of methacrylated alginate and acid monomers for concrete applications

Abstract

Polysaccharides, and especially alginate, can be useful for self-healing of cracks in concrete. Instead of weak electrostatic bonds present within calcium alginate, covalent bonds, by methacrylation of the polysaccharides, will result in mechanically stronger superabsorbent polymers (SAPs). These methacrylated alginate chains as backbone are combined with two acrylic monomers in a varying molar fraction. These SAPs show a moisture uptake capacity up to 110% their own weight at a relative humidity of 95%, with a negligible hysteresis. The swelling capacity increased (up to 246 times its own weight) with a decreasing acrylic acid/2 acrylamido-2-methylpropane sulfonic acid ratio. The SAPs also showed a thermal stability up to 200°C. Interestingly, the SAP composed of alginate and acrylic acid exerted a very limited decrease in compressive strength (up to 7% with addition of 1wt% SAP) rendering this material interesting for the envisaged self-healing application.

A Review of Self‐Healing Concrete for Damage Management of Structures

“…Although these hydrogels are biocompatible and biodegradable, they may feature disadvantages such as low mechanical strength and batch variation. Recently, Mignon et al modified alginates among others for use as self‐healing agent in concrete . These SAPs show a good stability in high pH cement filtrate solutions, are renewable, have a negligible effect on the compressive strength even upon addition of 1 mass% relative to the cement content, and result in a strong sealing capacity comparable to that obtained by commercial SAPs.…”

Photocrosslinked Alginate-Methacrylate Hydrogels with Modulable Mechanical Properties: Effect of the Molecular Conformation and Electron Density of the Methacrylate Reactive Group

“…All the samples were dissolved to 1% (w/v) in D 2 O. The G proportion in the ALG chain and the degree of methacrylation of the ALGMx macromers (also referred to as the degree of substitution or DS) were calculated from each corresponding spectrum according to Equations (1) and 2, respectively [25],…”

Crack Mitigation in Concrete: Superabsorbent Polymers as Key to Success?

“…Mignon et al [54,75] has developed modified alginate as a novel admixture for self-sealing and self-healing of mortar. For the same application, these alginates have also been tested with encapsulated carbonate producing bacteria [76].…”

“…To the best of our knowledge, the use of biopolymers for applications in mortar and concrete has only been reported scarcely. Nonetheless, these show great opportunities as they have proven to withstand high-pH cement filtrate solutions and are renewable [75]. Alginates can also be prepared at a reasonable cost.…”

“…On the other hand when cracks occur and water infiltrates the crevices, due to osmosis, the concentration of concentration of cations inside and outside the SAP will go to an equilibrium, as such increasing the swelling of the pH-responsive systems and making them more useful for the intended self-healing applications. This has already been tested for acrylate-based semi-synthetic SAPs based on methacrylated alginate combined with acrylic acid [75] but should definitely be a subject of further investigation.…”