Search

ABSTRACT To increase the recycling potential of concrete, Completely Recyclable Concrete (CRC) has been developed to be used as a raw material for cement clinker production. Sulfates may penetrate CRC [...]

ABSTRACT Service life predictions for concrete exposed to chloride-induced corrosion usually result from durability tests performed on uncracked concrete. Chloride migration coefficients for uncracked concrete should only be used if [...]

ABSTRACT To evaluate the global warming potential (GWP) of carbonation exposed high-volume fly ash (HVFA) concrete, its expected service life should be known. In the early stages of product development, [...]

In this work, the performance of mortar made with ferronickel slag (FNS) as cement replacement was investigated. The granulated FNS was ground to obtain a fineness higher than cement. To assess the performance of FNS in fresh and hardened mortar, the workability, flexural, and compressive strength were experimentally assessed. Based on the results obtained, the fluidity of mortar increased with increasing FNS content. It was found that FNS did not promote the compressive strength of mortar in the early days of curing, but at longer curing times the FNS starts to react. Although there is a decrease in flexural strength of mortar containing FNS, this result tends to be better than the compressive strength performance. The presence of FNS in mortar increased the porosity.

The service life of steel reinforced concrete in aggressive marine environments could be increased substantially by embedding a self-healing mechanism that ensures autonomous healing of cracks upon their occurrence. Previous proof-of-concept experiments have shown that the incorporation of encapsulated polymer-based healing agents (HAs) counts as a very appropriate way to achieve this goal. Over the years, several polymer-precursor-capsule systems have been developed in that perspective at our laboratory. Cementitious materials containing either commercial or in-house developed encapsulated HAs have been subjected to preliminary feasibility tests (water absorption, permeability tests, etc.). However, these experiments did not yet allow for a fast and straightforward assessment of the self-healing efficiency (SHE) in relation to the expected durability and service life performance of the material. This approach would have many advantages when having to select the most suitable polymer-precursor-capsule system for a particular concrete application. In this paper, a modified chloride migration test based on the one prescribed in NT Build 492 has been proposed to support the development of self-healing concrete for marine environments. Four polymer-based HAs have been screened that way, i.e. an in-house developed high-viscosity polyurethane (PU) precursor, a commercial low-viscosity PU precursor, the same commercial PU precursor with addition of accelerator and benzoyl peroxide (BPO), and an in-house developed 2-component acrylate-endcapped precursor + cross-linker. For now, a highly repeatable SHE value of 100% could only be obtained for the second option.