Possibilities of K-Value Determination for Active Admixtures with Respect to Durability

journal article in Web of Science

English

This paper discusses the possibility of determining k-values for active admixtures concerning durability factors such as the depth of penetration of water under pressure and the depth of carbonation of cement mortars with fly ash. The k-value considers the use of active admixtures in concrete when calculating the water/cement ratio and the equivalent amount of binder. Currently, only the effect of the active admixture on the compressive strength of concrete and cement mortars is considered when determining the k-value, but not the effect of the active admixture on durability. To account for the influence of durability factors on the determination of the k-value, the mathematical functions of the property, dependent on the water/cement ratio and the age of the cement mortar, were constructed using regression analysis. From the determined functions, it was then possible to use an optimisation problem to determine the k-value so the difference between the actual measurement and calculated depth of pressure water seepage or carbonation was as small as possible. A high coefficient of determination of 0.9855 was achieved for the pressure water seepage depth function, but the coefficient of determination for the carbonation depth was lower.

k-value; activity index; supplementary cementitious materials; fly ash; durability

ŠPERLING, P.; HUBÁČEK, A.; HELA, R.; STARÁ, T.; DVOŘÁK, R.

12. 5. 2025

MDPI

BASEL

1996-1944

Materials

18

10

Swiss Confederation

25

https://www.mdpi.com/1996-1944/18/10/2227