Characterisation of Limestone and Fly Ash for a Rational Use in Concrete

Magarotto, Roberta; Moratti, Francesca; Zeminian, Nicoletta

doi:10.1680/ccfdc.34013.0008

Cited by 2 publications

(3 citation statements)

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“…Sulfates are contained in every Portland cement, both as alkali sulfates originating from the combustion of sulfurous fuel which produces SO 3 , and from the addition of calcium sulfates for set control of cement. Depending on the manufacturer, significant variations in the sulfate contents of individual cement samples can occur, whereby high sulfate concentrations can severely impede the effectiveness of PCE polymers (“sulfate effect”) 10…”

Section: Resultsmentioning

confidence: 99%

“…Previous works have clearly shown the strong influence of alkali sulfates present in cement on the performance of PCEs as a result of their rapid dissolution and thus release of sulfate ions 7, 9, 10. First, some researchers found that the sulfate content present in cement can significantly impede the flowability of the slurries containing PCE 9, 10. Opposite to this trend it was demonstrated that a high dosage of K 2 SO 4 may in fact enhance the workability retention (“slump loss behavior”) of certain PCEs 10.…”

Section: Introductionmentioning

confidence: 99%

“…First, some researchers found that the sulfate content present in cement can significantly impede the flowability of the slurries containing PCE 9, 10. Opposite to this trend it was demonstrated that a high dosage of K 2 SO 4 may in fact enhance the workability retention (“slump loss behavior”) of certain PCEs 10. Consequently, some researchers believe that an optimum content of alkali sulfate exists for PCE performance 11.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and performance of a modified polycarboxylate dispersant for concrete possessing enhanced cement compatibility

Habbaba

Lange

Plank

2012

J of Applied Polymer Sci

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It is well established that the performance of polycarboxylate (PCE) superplasticizers can be severely affected by the composition of individual cements. Here, a novel allylether/maleic anhydride (APEG)-based PCE was synthesized using allyl maleate monomer as a new, additional building block. When polymerized into the PCE main chain, this building block was found to form a cyclic lactone structure. The resulting PCE molecule was tested with respect to the dispersing force in cements possessing different phase compositions and alkali sulfate (K 2 SO 4 ) contents. These data were compared with those from conventional APEG-and methacrylate ester (MPEG)-type PCEs. Results obtained from cement paste flowability and adsorption measurements suggest that the modified PCE disperses all cement samples well and hence is more robust against variations in cement composition. Apparently, the new building block induces a higher affinity of the polymer to the surface of cement and can form a denser polymer layer.

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Section: Resultsmentioning

confidence: 99%