The purpose of this international conference is to present the latest scientific and technical information in the field of supplementary cementitious materials and novel binders for use in concrete. The new aspect of this conference is to highlight advances in the field of alternative and sustainable binders and supplementary cementitious materials, which are receiving increasing attention from the research community. The conference was held in Montréal, Canada from October 2 to 4, 2017. The conference proceedings, containing 50 refereed papers from more than 33 countries, were published as ACI SP-320.

Although notable advances have been made in recent years in elucidating the relationship between the nature of the precursor and the activation conditions used for production of alkali-activated materials (AAMs), it remains largely unknown whether these materials can withstand various environmental threats during their service life. The interaction between a cementitious material and the CO2 present in the air is referred to as carbonation, and while this is largely a well understood phenomenon for portland cement systems, its long-term effects in AAMs are unknown. This is a consequence of the large number of variables controlling microstructural development and therefore macro-scale properties of AAMs, and the lack of standardized methodologies for testing their carbonation resistance. This study reports an overview of recently identified factors inducing microstructural changes in AAMs upon exposure to CO2, and the influence of carbonation on the corrosion resistance of some steel reinforced AAMs.

This paper presents results obtained from steel-reinforced concrete specimens retrieved after 25 to 27 years of exposure in a marine environment. The specimens included mixtures with various SCM blends (25% fly ash, 10% silica fume and 50% slag), as well as a mixture without any SCM, all at a W/CM of 0.50. Testing included chloride-ion depth determination, rapid chloride permeability test, bulk electrical resistivity test and electrochemical corrosion-monitoring. The chloride profiles revealed that SCM incorporation leads to a significant decrease in chloride-ion penetration, which was supported by rapid chloride permeability and bulk electrical resistivity tests. Electrochemical corrosionmonitoring showed passivity for all reinforcements at a cover depth of 70 mm or more for specimens incorporating SCMs, while for specimens not containing SCMs, all reinforcements, up to a cover depth of 140 mm, showed active corrosion. Finally, it was found that the reinforcement corrosion rate in SCM concrete was significantly lower than that for portland cement concrete.

In this paper, it is shown that Class F fly ash can be effectively used in high volumes as a supplementary cementitious material. High Volume Fly Ash (HVFA) use is of interest in promoting the development and application of green materials. In South Africa, there is little or no literature on high volume incorporation of locally available fly ash in concrete. In this investigation, six different concrete mixtures with water/cementitious ratios of 0.3 and 0.45, were used. The mixtures consisted of 0, 30, 50 and 70% fly ash. Tests carried out were workability, compressive strength and heat of hydration. Large 300 mm cubes were used to study hydration heat development in fresh concrete. As expected, concrete strength decreased as fly ash content increased owing to the slower rate of strength development in fly ash mixtures. It was found that heat of hydration generated in HVFA mixtures gave lower peak temperatures compared to mixtures without fly ash, producing reductions of 27% to 43.5% in peak temperatures for mixtures containing 50% and 70% fly ash respectively. Temperature simulation using ConcreteWorks gave predictions correctly depicting the measured temperature profiles but with slight under-estimation of peak temperatures.

The natural, e.g. autogenous, healing capacity of cementitious materials in concrete is a promising path to overcome the ecological problems and durability preoccupations inherent to civil engineering. But, recovery of mechanical from autogenous healing are due to ongoing hydration reactions highly dependent on the binder. In this study, the healing potential of different mixtures incorporating supplementary cementitious materials is discussed both from a mechanical and a permeability point of view. Mortars with a 25% cement mass substitution ratio by metakaolin or blast furnace slag were compared to reference ones. Healing performances were quantified after cracking at early age using three-point-bending tests. Recovery in mechanical properties were calculated from reloading curves while permeability recovery was estimated using a novel air permeability device. It appears that the blast furnace slag mixture exhibits very good performance compared to the reference and the one including metakaolin is relatively close to the reference.