Building materials

The present work systematically investigates the influence of silica fume and organosilane addition on the hydration dynamics and the capillary pore formation of a cement paste. The cement samples were prepared with two water-to-cement ratios with increasing amounts of silica fume and of (3-Aminopropyl)triethoxysilane (APTES) organosilane. Low-field 1H nuclear magnetic resonance (NMR) relaxation measurements were performed …

The Effect of Silica Fume and Organosilane Addition on the Porosity of Cement Paste Read More »

Binders with large portions of carbon-intensive Portland cement replaced by supplementary cementitious materials (e.g. fly ash) are more susceptible to carbonation mainly due to their lower CO2 buffering capacity. This conclusion is usually drawn from accelerated experiments at elevated CO2 levels involving processes that seriously differ from natural carbonation. The resulting presence of H2O reactant in the …

Natural and accelerated carbonation behaviour of high-volume fly ash (HVFA) mortar: Effects on internal moisture, microstructure and carbonated phase proportioning Read More »

Moisture is a main cause for weathering effects in historical façades made of natural stones. If applied correctly, hydrophobic agents can successfully protect these façades without altering the appearance. The major challenge is to ensure the required surface penetration. In-situ measurements for quality assurance on historical façades are still mainly done destructively through the extraction …

Single-sided NMR as a non-destructive method for quality evaluation of hydrophobic treatments on natural stones Read More »

Quantitative determination of moisture with nuclear magnetic resonance is usually a simple task, since the initial amplitude is proportional to the moisture content. However, situations can arise where the combination of short relaxation times, low signal-to-noise ratio and the ill-posed nature of the inverse Laplace transformation lead to a significant bias of the initial amplitude impeding it being an …

Generalised NMR-moisture correlation function of building materials based on a capillary bundle model Read More »

In this study, single-sided proton nuclear magnetic resonance (1H NMR) was used to quantify the porosity of the concrete cover. Laboratory concrete samples were prepared with different formwork surfaces as well as varying fresh concrete pressures. Furthermore, to separate the influence of aggregates on porosity, hardened cement paste and mortar samples of otherwise similar composition …

Influence of fresh concrete pressure on cover porosity investigated by single-sided 1H NMR Read More »

Die AKR‐Schadensevolution von Betonfahrbahndecken ist in der Anfangsphase durch eine Dunkelfärbung der Oberfläche im Fugenbereich gekennzeichnet. Es wird vermutet, dass eine erhöhte Durchfeuchtung der Betonrandzone ursächlich für diese Erscheinung ist. Vor diesem Hintergrund wurde exemplarisch eine Fahrbahnplatte eines repräsentativen Bundesautobahnabschnitts systematisch mit verschiedenartiger zerstörungsfreier Prüftechnik vor Ort untersucht. Die Ergebnisse der zunächst erfolgten großflächigen Durchmusterung …

Dunkelfärbung der Betonfahrbahndecke im AKR-Kontext Read More »