Abstract
The dispersing effectiveness of five commercial plasticizers; lignosulfonate (LS), naphthalene sulphonate–
formaldehyde polycondensate (NSF) and three polycarboxylate ethers (PCEs) were quantitatively
investigated in blended cements where ordinary Portland cement (OPC) was partly replaced by calcined
marl (CM) up to 60%. CM drastically viscosified and decreased the flow of the cement due to high absorption
of water. The performance of plasticizers mimics that in the OPC system except when PCEs were
added. PCEs possessing long side chains were less effective as dispersants due to the consumption of
these polymers via the ability of their PEO side chains to intercalate between the remaining layers in
the calcined clay. Higher dosages were thus needed for effective dispersion. The decrease in PCE–OPC
interaction led to little retardation in cement hydration except at high polymer dosages, whereas the
performance of NSF and LS in CM blended cement is driven by clinker content.
formaldehyde polycondensate (NSF) and three polycarboxylate ethers (PCEs) were quantitatively
investigated in blended cements where ordinary Portland cement (OPC) was partly replaced by calcined
marl (CM) up to 60%. CM drastically viscosified and decreased the flow of the cement due to high absorption
of water. The performance of plasticizers mimics that in the OPC system except when PCEs were
added. PCEs possessing long side chains were less effective as dispersants due to the consumption of
these polymers via the ability of their PEO side chains to intercalate between the remaining layers in
the calcined clay. Higher dosages were thus needed for effective dispersion. The decrease in PCE–OPC
interaction led to little retardation in cement hydration except at high polymer dosages, whereas the
performance of NSF and LS in CM blended cement is driven by clinker content.
