G. Cygan

The Effect of Temperature on the Rheological Properties of Self-Compacting Concrete

In the paper the methodology and results of investigation of the influence of temperature and time on the rheological properties of cement paste and different in cement paste volume fresh self compacting concrete are presented and discussed. The influence of temperature on the rheology of mortar analogous to mortar that fills voids of coarse aggregate in the self compacting concretes was additionally the subject of investigation. It was found that the influence of temperature on rheological parameters of fresh cement paste and concrete may be significantly different, whereas on rheological parameters of fresh mortar and concrete is generally similar for both these materials. Discussion on the test results concern possible mechanisms of temperature influence on rheological properties of fresh cement paste, mortar and concrete. It is concluded that testing cement paste is not sufficient for designing and development of self-compacting concrete in respect to changing temperature. For predicting trends of changes in rheological behaviour of fresh self compacting concrete in changing temperature tests made on mortars are necessary.

Designing the composition of concrete mixtures based on properties of mortar

The research was nanced by the project No. 0842/B/T02/2011/40 from the National Science Centre and the project “DoktoRIS – Scholarship program for innovative Silesia” co- nanced by the European Union under the European Social Fund.

The influence of composition on thixotropic behaviour of cement mortar

This paper presents methods of measurement and results of rheological properties including the thixitropic stiffening of designed cement mortars. The aim of the study is to determine the effect of the type of cement, w/c ratio, and chemical admixtures on the selected rheological properties of mortars. It will allow a better understanding of the nature of previously observed decreasing formwork pressure when using self-compacting concrete.

Influence of Temperature on Workability and Compressive Strength of Ordinary Concrete with High Calcium Fly Ash

Abstract The rheological properties of fresh ordinary concrete are closely affected by temperature and time. The paper presents the study of consistency of fresh concrete mixtures made with Portland cement and cement with calcareous fly ash. Two types of admixtures were used. It was proven that the temperature has a clear effect on workability and compressive strength concrete. Influence on workability can be reduced by selecting the appropriate superplasticizer and cement.

Laser System for Testing Early Shrinkage of Concrete Elements in Conjuction with the Deterioration of the Setting Time

Abstract The paper presents a method for testing the shrinkage of concrete beams with dimensions of 10x10x50cm. Measurements followed from setting into the form until 24 hours after setting. It was used modified TLS system, which originally was meant for the determination of changes in the length of thin-mortar. Simultanously measured were the changes of speed propagation of sound waves by Vikasonic, what allows to specify the setting time of binders. It could be a base for determining the scratch resistance of the concrete in the first 24 hours after casting.

The effect of temperature on the properties of fresh self-compacting concrete

Abstract The rheological properties of self-compacting concrete are closely influenced by temperature and the time. Previous studies which aim was to research the effect of temperature on self-compacting concrete workability, showed that the behaviour of fresh SCC at varying temperatures differs from that of normal vibrated concrete. The paper presents the study of rheological properties of fresh self-compacting concrete mixtures made with portland, blast furnace and component cement. Two types of superplasticizers were used. It was proven that temperature has a clear effect on workability; it can be reduced by selecting the appropriate superplasticizer and cement.

The influence of temperature on thixotropic behaviour of cement mortar

This paper presents methods of measurement and results of rheological properties including thixitropic stiffening of designed cement mortars. The aim of the study is to determine the temperature rheological properties of selected mortars. It will help the industry to better understand and describe the nature of the previously observed decreasing formwork pressure using self-compacting concrete.