Seminar Series February 2014 : How Drying Technique and Gel Chemistry Affect The Durability Indicator Of Alkali Activated Materials

seminar 02 06


Date: 12th February 2014 (Wed)
Time: 2.30 pm - 3.30 pm

Venue:  TMM, Level 1, FK

Speaker : DR IDAWATI ISMAIL

Title: HOW DRYING TECHNIQUE AND GEL CHEMISTRY EFFECT THE DURABILITY INDICATOR OF ALKALI ACTIVATED MATERIALS
 

The divergence between measured water uptake and chloride permeability in alkali-activated specimens is attributed largely due to the specified standard preconditioning (drying) of the samples prior to water absorption testing due to the difference in water environments as a function of slag/fly ash ratio. Drying is likely to be inducing desiccation and consequent microcracking of slag-based binding gels, while less disturbance occurs in a fly ash geopolymer gel. The chemistry of the binding gels in these alkali-activated systems significantly controls the mass and ionic transport in chloride-containing environments. Although higher porosity was measured by these standards, a denser Al-substituted calcium silicate hydrate (C–A–S–H) gel contributes to a higher mechanical strength, and durability under chloride exposure. The inclusion of fly ash promotes the formation of more porous sodium aluminosilicate (N–A–S–H) type gels, reducing the resistance to transport.

Click here to view abstract from previous Seminar Series.

By: Dr Md Rezaur Rahman

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