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Experimental assessment of the casting position factor of reinforcing bars in high performance concretes (HPC, HPSCC)

Dybeł Piotr, Kucharska Milena

Archives of Civil and Mechanical Engineering

2019

Vol. 19, no. 1

127--136

This paper concerns the problem of the experimental assessment of the casting position factor in comparison to the current normative guidelines. Our experiment was performed on three types of concrete: high-performance concrete (HPC), high-performance self-compacting concrete (HPSCC) and normal strength concrete (NSC) used as a reference. The HPC and the HPSCC were made in respectively, two and four different variants that differed in the content of silica fume. To assess the casting position factor, three types of elements with heights of 480, 800 and 1600 mm were used. In each element, a ribbed reinforcing bar with a diameter of 16 mm was embedded perpendicularly to the direction of concreting. The bond was examined using pull-out test. The test results showed that regardless of the type and composition of concrete, the linear change of the casting position factor with element's height was observed. No significant differences in the changes of the casting position factor with height were noted between the HPC and the HPSCC. The experiment revealed that the new generation concretes were characterized by a much lower value of the casting position factor in comparison to the current normative guidelines.

The effect of calcareous fly ash on selected properties of new generation of concrete

Gołaszewski J., Ponikiewski T.

Roads and Bridges - Drogi i Mosty

2013

Vol. 12, no. 2

209-222

The analysis of the effect of calcareous fly ash on selected properties of self-compacting and high performance self-compacting concretes is the subject of this paper. The investigation included the variable degree of grinding of calcareous fly ash and a different type of cement modified with calcareous fly ash. The results of tests on the SF class of flow and viscosity grade T500 of tested mixtures, as well as tests on concrete compressive strength e (F cm,28, fcm 90), flexural strength (fcf,28, fcf,90), absorption tests and tests on water penetration depth are presented. Concrete mixture was modified using a variable volume fraction of calcareous fly ash as a type I and type I I additive (10, 20 or 30%) . The studies confirmed the possibility of using calcareous fly ash in self-compacting and high performance self-compacting concretes, while maintaining the assumed workability.

Analiza wpływu zawartości popiołu lotnego wapiennego na wybrane właściwości betonów samozagęszczalnych i wysokowartościowych betonów samozagęszczalnych jest przedmiotem niniejszego artykułu. Zakres badań obejmował zmienny stopień domielenia popiołu lotnego wapiennego oraz rodzaj cementu modyfikowanego popiołem lotnym wapiennym. Przedstawiono wyniki badań klasy rozpływu SF oraz klasy lepkości T500 mieszanek betonowych oraz wytrzymałości na ściskani e (F cm,28, fcm 90) wytrzymałośc i n a zginani (fcf,28, fcf,90) nasiąkliwości betonu i głębokości penetracji wody. Popiół lotny wapienny stosowano w zmiennej ilości (10, 20 i 30%) jako dodatek typu I oraz dodatku typu II. Wyniki badań potwierdziły możliwość stosowania popiołu lotnego wapiennego w betonach samozagęszczalnych i wysokowartościowych betonach samozagęszczalnych przy zachowaniu zakładanej urabialności mieszanek.