Influence of the composition of powder-type SCC on conversion factors for compressive strength

Abstract

Depending on practical considerations and standards, different types of test specimens are used for the determination of the uniaxial compressive strength of concrete. Appropriate conversion factors, also referred to as shape factors, are needed to convert the compressive strength as determined on one type of specimen to the equivalent compressive strength of another type of specimen. As such shape factors for vibrated concrete are influenced by the composition of the concrete, questions arise concerning the factors that affect the shape factors for powder-type self-compacting concrete (SCC). This paper describes the findings of an extensive research programme performed by three laboratories on the influencing parameters of the shape factors for SCC. Concrete composition parameters such as powder content, cement/powder ratio, water/cement ratio and the type of coarse aggregates, cement, filler and plasticiser appear to have little effect on the experimentally obtained shape factors. Any possible influence on compressive strength was overshadowed by experimental scatter

Effect of ultra-fine fly ash on concrete performance and durability

“…Fifteen cubes (with side 100 mm or 150 mm) and four cylinders (with height 200 mm and diameter 100 mm) were produced per mix according to EN 206:2013+A1:2016 [39] and resulting in a total of 152 specimens to test mechanical properties and durability. According to research of Van Der Vurst et al [40], in case of high strength concrete, it is considered that the shape/size factor between cubes with side 100 mm and cubes with side 150 mm is more or less equal to one.…”

Predictive strength of ready‐mixed concrete: Exemplified using data from the Norwegian market

“…The compressive strength in the structure was thus represented by a log‐normally distributed variable with mean and coefficient of variation. assuming that Equations and are valid approximations. It should be noted that the ratio between the cylinder and cube strength also has a significant coefficient of variation which should be taken into account in Equation if a detailed strength prediction is necessary. However, for the present application examples, the nominal ratio was assumed sufficient.…”

“…Foster et al report from a study on a collection of strength recordings from Australia, and it can be shown that the 28‐day compressive strength of lab‐cured cylinders can be represented by a normally distributed variable with mean μ c =1.21 f ck and a coefficient of variation of V c =0.12. Correlation with other material parameters for concrete can be found elsewhere, and the relation between cylinder and cube strength is discussed in several contributions …”