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2 Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

2 2009

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The properties of cement concretes modified with superplasticizers

Kapelko A., Kapelko R.

Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

2009

z. 53 [265]

85-94

The properties of grouts, mortars and concrete mixtures with four different superplasticizers have been investigated. We determined the plasticizing and setting time of cement, the plasticizing and shrinkage of mortars, the consistency change of concrete mixtures as a function of time using the slump and flow tests, and the compressive strength and water absorption of cement concrete. The investigations carried out show the significant impact of superplasticizers on the plasticizing of cement grouts and on the shortening of their setting time. The shrinkage of mortars depends on the type of superplasticizer. Furthermore, the consistency change as a function of time depends on the type of superplasticizer and indicates the possibilities of lengthening the time of workability maintenance of mixtures with those superplasticizers. The linear relationship was found between the values of the slump loss and the slump flow as a function of time. The superplasticizers used significantly lower the water absorption of concrete and increase the quality of those concretes by 1-2 classes as compared with the concrete without admixture. The investigations into cement concrete with superplasticizer indicate the possibilities of regulation of concrete mixtures consistency and selecting the adequate mean of transportation and placing, as well as some cement savings.

Effectiveness of complex modificators in concrete

Pozniak O., Marushchak U., Mazurak O., Medvedyk Z.

Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

2009

z. 53 [265]

125-130

The paper is devoted to obtain high performance concrete with complex modificators and investigation of its exploitative properties. It was shown, that improved characteristic of concrete are achieved by optimal granulometric composition of fine, coarse aggregates and complex modificators plastifying and accelerating on the basis of sulphonaftalin-formaldehydes, polycarboxylates and highly soluble electrolytes, such as sodium tiosulfate and rodanide. The optimal compositions of complex modificators due synergic action of their ingredients allowed to obtain concrete with improved properties durability and provided efficiency in monolithic building.