Durability of Concrete Containing Calcined Clays: Comparison of Illite and Low-Grade Kaolin

TIRONI, ALEJANDRA; ZITO, SILVINA; IRASSAR, EDGARDO F.; CORDOBA, GISELA P.; RAHHAL, VIVIANA F.

RILEM Bookserie

Springer

Año: 2020 vol. 25 p. 631 - 640

2211-0844

In this paper, durability parameters (water sorptivity, water penetration, chloride penetration and natural carbonation) are studied on conventional mixtures (w/cm = 0.50). Concretes were elaborated with Portland cement (PC) and blended Portland cements, containing 25% replacement by illitic calcined clay (ICC) and low-grade kaolinitic calcined clay (KCC). They were characterized by slump, compressive and tensile strengths and bulk porosity. Water sorptivity (ASTM C 1585) was determined on concretes cured 2, 7 and 28 days; water penetration test (EN 12390) and chloride penetration (ASTM C 1556) were determined on concretes cured 28 days. Carbonation depth undergoing a good and very good curing was assessed using a phenolphthalein indicator at 3 and 6 months of natural exposition. Results show that water sorptivity is reduced when concrete is curing for 2, 7 and 28 days for all concretes. KCC has a significantly lower sorptivity than PCC and ICC. At 28 days, the water penetration is deeper for ICC and lower for KCC concrete. All concretes have similar apparent chloride diffusion coefficients. After six months, the natural carbonation of all concretes is less than 2 mm, with a slightly lower performance of ICC and KCC than PCC.