| dc.description.abstract | This paper presents findings of an experimental investigation on sodium sulphate
(Na2SO4) activated calcined clay e Portland cement blends in sulphuric acid media.
Calcined clays were blended with Ordinary Portland Cement (OPC) at replacement
levels of 40% 45% and 50 % by mass of OPC to make blended cement labelled
PCC40, PCC45 and PCC50 respectively. Initially, pozzolanicity and setting time
tests were conducted. Mortar prisms measuring 40 mm 40 mm 160 mm were
cast using 0.5M Na2SO4 solution and their compressive strengths determined on the
2nd, 7th, 28th and 90 th day of curing. The 28th day cured mortar prisms were
subjected to porosity test. Moreover, 5 5 5 cm mortar cubes were also prepared
and their weight and strength loss was taken as a measure of their acid resistivity
after an immersion time of 7, 14, 28, 56, 84 and 120 days in 3 % of sulphuric acid
at 23 1 C. OPC, commercial Portland Pozzolana Cement (PPC) and PCC40,
PCC45 and PCC50 cement were cast using water and similarly investigated for
comparison purposes. The results obtained showed that chemically activated
cements exhibited higher pozzolanic activity, lower porosity, shorter setting times
and higher resistance to acid attack compared to non-activated cements. However,
OPC was found to be non-pozzolanic. | en_US |
