Jean-Louis Cabiron

Bio: Jean-Louis Cabiron is an academic researcher from Lafarge. The author has contributed to research in topics: Cementitious & Calcium aluminate cements. The author has an hindex of 1, co-authored 1 publications receiving 237 citations.

High-performance concretes from calcium aluminate cements

Abstract: Calcium aluminate cements have a radically different chemistry to Portland cements. Due principally to their higher cost, they do not compete directly with Portland cements. Nevertheless, concretes based on these cements have very high performance in specific applications. Two of these are discussed in this article: resistance to acid attack and particularly biogenic corrosion and abrasion resistance in hydraulic structures. Such applications extend the range of applications for cementitious materials.

2 – Calcium aluminate cements

Abstract: In terms of the length of time it has been produced, the volume produced and the breadth of applications, calcium aluminate cements are by far the most important class of non-Portland cements. Calcium aluminate cements are a relatively large family with a range of compositions which varies much more widely than Portland cement. Today the two major markets for calcium aluminate cement are in castable refractories and in dry mix mortars for special construction applications, which together account for around 80% of consumption. The use in technical concretes, for example, sewer linings, rapid repair, etc. is rather small. Calcium aluminate cements are known for their rapid strength gain, especially at low temperatures, superior durability across several categories and high temperature resistance. Their ability to consume water rapidly during hydration makes them a preferred component in building chemistry applications as this contributes to construction expediency. CACs are highly versatile materials that can be used as the full binding material, or as is more common, a component of a blended system where the contribution is based on the final desired properties.

Corrosion resistance in activated fly ash mortars

Abstract: The question of whether reinforcing steel can be protected with activated fly ash cement as effectively as with Portland cement is explored in this study. Corrosion potential ( E corr ) and polarisation resistance ( R p ) values for steel electrodes embedded in Portland cement mortar and two fly ash mortars, respectively activated with NaOH and waterglass+NaOH solutions, are monitored. Chloride-free activated fly ash mortars are found to passivate steel reinforcement as speedily and effectively as Portland cement mortars, giving no cause to fear that corrosion may limit the durability of reinforced concrete structures built with these new types of activated fly ash cement. The polarisation curves and the response to short-term anodic current pulses (galvanostatic pulse technique) obtained further corroborate the full and stable passivation of the steel by the concrete manufactured with these binders.

Dehydration of a layered double hydroxide – C2AH8

Abstract: Thermal dehydration of dicalcium aluminate hydrate, C2AH8, has been investigated by simultaneous differential thermal and thermo gravimetric analysis (DTA/TGA), powder X-ray diffraction (XRD), temperature-dependent infrared spectroscopy (FT-IR), and BET method of surface area measurement. The temperature-dependent infrared measurements were studied by two-dimensional infrared (2D-IR) correlation spectroscopy. The structure of aluminum-oxide polyhedron, characterized by 27Al solid state NMR spectrum method and FT-IR, shows tetrahedron and octahedron as the main forms of aluminum-oxide polyhedrons in C2AH8 sample. From the results obtained a variety of structural transformations observed are explained as a consequence of the removal of loosely held interlayer water molecules at lower temperatures, followed by grafting process of the interlayer [Al(OH)4]− anion. Structural model of a grafting process of the interlayer [Al(OH)4]− tetrahedron onto hydroxylated octahedrons of [Ca2Al(OH)6]+ layers has been proposed in order to explain observed loss of one water molecule, shrinkage of interlayer spacing and qualitative changes of FT-IR spectra. At higher temperatures the dehydroxylation of the lattice and decomposition of the interlayer species occurs, yielding amorphous material that crystallizes into C3A and C12A7 at 885 °C. Those findings provide improvement in the interpretation of thermo-analytical results of calcium aluminate cements (CAC) hydration products, and better understanding of CAC conversion process.

Application of ultrasonic testing to describe the hydration of calcium aluminate cement at the early age

Abstract: Nondestructive and in situ characterisation techniques, such as ultrasonic measurements, permit to follow cement hydration at the early age from a few minutes to a few hours after mixing. The technique reported in this paper is based on measurements in reflection modes. Results concerning an aluminous cement, Secar71, are presented (water-to-cement weight ratio (W/C): 0.3 and 0.4; temperature of measurement: 20°C; duration: 0–24 h). Information deduced from ultrasonic measurements (longitudinal wave velocity, reflection coefficient) associated with other data obtained from X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetric (TG) measurements enable to propose a qualitative description of hydration's chronology. The sensitivity of these ultrasonic parameters to hydrates formation and structuring is underlined.

High temperature material properties of calcium aluminate cement concrete

Abstract: In this study, material properties of calcium aluminate cement concrete (CACC) were investigated at various temperatures of 23, 200, 400, 600 and 800 °C. Material properties namely compressive strength, splitting tensile strength, elastic modulus, stress–strain response, mass loss and compressive toughness were measured using unstressed and residual test methods. High temperature performance of CACC was compared with conventional normal strength concrete (NSC). Data from high temperature tests of CACC revealed that the presence of alumina as a binding agent showed considerable enhancement in the mechanical performance compared to NSC. At elevated temperatures, reduction in the stress–strain response was observed in both CACC and NSC; however, increase in axial strain was more in case of CACC. Compressive toughness was higher in case of CACC as compared to NSC which increases up to 200 °C, but decreases beyond this temperature. Scanning electron microscope (SEM) was used to differentiate the microstructural changes in both types of concrete at temperatures up to 600 °C. Visual investigations after high temperature exposure revealed that CACC exhibits low cracking with less color changes as compared to NSC. Data generated from material property tests was utilized to develop simplified relations for expressing material properties of CACC as a function of temperature.