Time dependency of chloride migration coefficient in self-compacting concrete

The chloride diffusion coefficient of concrete is strongly decreasing in time. Neglecting this aspect in the modelling of the diffusion process will overestimate the chloride penetration depth and thus lead to an uneconomic design. In order to get an accurate insight in this decreasing process, 16 self-compacting concrete mixes were made. Four types of cement (portland cement and blast furnace slag cement), three types of filler (fly ash and two types of limestone filler with a different grading curve) and two types of coarse aggregate are used and the influence of the amount of powder and the amount of water is studied. The chloride migration coefficient was experimentally determined with the non-steady state migration test, developed by Tang et al. and described in NT BUILD 492, and making use of an electrical field. This migration coefficient was determined at different concrete ages, up to 5 year. From the migration tests, the diffusion coefficients were deduced. The decrease in time of the diffusion coefficients is studied and modelled. Both the experimental and modelling results will be presented and discussed in the paper.

ISBN:978-2-35158-073-8

Jaar van publicatie:2009

Toegankelijkheid:Closed