DETERMINATION OF PORE STRUCTURE CHARACTERISTIC OF MORTAR USING A STEADY-STATE MIGRATION TEST

Pore structure characteristic of a hardened mortar is quantified as a pore structure coefficient (PSC) that is defined and calculated in this research using an effective diffusion coefficient obtained from a migration test. PSC is composed of porosity and tortuosity. PSC was found to be controlled partially by the amount of pores ranged from 100nm to 2μm in the diameter. Potassium ion as a tracer ion in the migration test provided reasonably consistent PSC as well as chloride ion. Larger tortuosity of fly ash mortar resulted in lower PSC despite larger porosity. The PSC for fly ash mortar appeared to account for part of micro pores that may reduce ionic diffusion. An electrical effect of the micro pores would seem to restrict the movement of diffusing ions.