Some properties of concrete containing high fraction volume of metakaolin

الملخص EN

In this research, a study has been made on the effect of high fractional volume of replacement Metakaolin that results from grinding and burning the local kaolin from (Doeakhla zone / west of Baghdad / Iraq) with fineness of 18000 cm2 / gm., and with temperature 700°C for one hour, on some properties of concrete (compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, density, absorption and drying shrinkage).

Also, non-destructive tests have been made (Schmidt rebound hummer and Ultrasonic pulse velocity).

In this study, ten concrete mixes have been used in two Groups to get a compressive strength 40 N/mm2 at 28 days.

In Group A, the percentage replace of Metakaolin have been changed from (0-70) % by weight of cement with percent increment equal to 10 % for each mix, and change the maximum size of aggregates to determine the effect of changing the surface area of aggregate as variable on the properties of concrete-containing Metakaolin, The tests for all mixes were made at ages ranged from 1 day to 90 days after mixing and replacement a dosage of superplasticizer by water content of the mix to make a constant workability with slump 50 ± 5mm.

The aim of this research is to find a type of concrete that can be used in dams as one of the types of mass concrete, concluded from this research that replacing 70 % Metakaolin instead of cement mixing the compressive strength aged 90 days less than the 63%, splitting strength at 28 days less than 27 %, flexural strength at 28 days less than about 27 %, the modulus of elasticity at 28 days less than 54 %, density of less than about 8 % at 28 days, the absorption rate increases about 27 % and drying shrinkage 1.65 * 10-4 at 60 days when compared all these tests with the reference concrete.