Influence of Limestone Fillers on the Properties of Concrete
Can cement in concrete be reduced without having any adverse effects on the properties of concrete?
Saturation Dosages for Cement Pastes
1. Class 1 Cement Pastes (25% Cement Reduction)
The following observations were made:
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The limestone addition have an effect on the superplasticizer saturation dosage,
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The control achieved saturation at a very low dosage,
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The superplasticizer is more efficient on the cement particles and also the cement particles could have a higher affinity for the adsorption of the superplasticizer when compared to the limestone fines.
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The surface area induced in the mix has an effect on the saturation dosages. The finer the fillers, the higher is the surface area, and the lower is the saturation dosage.
2. Class 2 Cement Pastes (50% Cement Reduction)
As the replacement level increased, the following observations were made:
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The superplasticizer demand in some cases increased due to a possible decrease in the packing density of the mixes.
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In other cases, the superplasticizer demand remained the same as Class 1.
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A decrease can be found for some mixes, which could also be possibly due to the achievement of a better packing density in the mix.
Concluding Remarks
The limestone addition have an influence on the saturation dosage. However, it is difficult to determine the influence of the different sized fillers on the flow properties as the trend obtained from the Marsh cone test is not very clear.