Effect of temperature on physico-mechanical properties of artificial pozzolana-cement pastes containing burnt water sludge

Abstract EN

An experimental investigation was conducted to evaluate the influence of elevated temperatures on the compressive strength, phase composition of blended cement pastes.

The blended cement used in this investigation consists of ordinary Portland cement (Cem.

1), raw and burnt sludge.

The blended cement pastes were prepared using the standard water of consistency.

The fresh cement pastes were first cured at 100 % relative humidity for 24 hours and then cured under water for 28 days.

The hardened pastes, thus produced, were thermally treated at 100, 200, 300, 400, 600 and 800 oC for 2 hours.

Compressive strength, phase composition and chemically combined water were measured on the fired specimens representing the studied blended cement pastes and compared with those of the neat ordinary Portland cement paste (Cem.I).

The obtained results showed that the addition of burnt sludge to OPC improved the performance of the produced blended cement pastes when exposed to elevated temperatures.

The results of this investigation showed also, an increase of compressive strength of the studied blended cement mixes with the exposed temperature up to 200oC, followed by a slight decrease gradual decrease up to 600oC and finally a sharp decrease at 800ºC.

It is also clear that, a recrystallization and deformation of CSH, C4AH13 were occurred as a result of thermal treatment.