70 years of measuring air content ­according to Boyle-Mariotte

It has been known since the 1940 s that deliberate air entrainment increases the frost and freeze-thaw resistance of hardened concrete. This is why the air content of fresh concrete and its correlation with the air content of hardened concrete must be determined prior to concrete pouring. Following the exclusive application of the volumetric measurement method (“rolling method”) in the early years, Klein published the option of measuring the air content of concrete by applying Boyle-Mariotte’s law and presented the first “pressure air meter”.

This device served as a basis from which Type A with...

Related articles:

Issue 02/2016 An innovative design concept for formwork systems

Fresh concrete pressure for free-form structural ­concrete components –

Structural concrete components with inclined and/or curved surfaces are becoming increasingly popular in contemporary architecture (Fig. 1). Such concrete structures have long been the state of the...

more
Issue 07/2024

Influence of hydration and water content on the brightness of hardened cement paste

Modern concrete construction elements are subject not only to wide-ranging requirements but must frequently satisfy demanding aesthetic expectations such as a defined color. In this context, the color...

more
Issue 09/2015 Woma

Cold water high-pressure cleaner for concrete formwork

Woma GmbH presents its cold water high-pressure EcoCold 500/30 Classic for use in a day-to-day rugged work environment. EcoCold features a Kärcher high-pressure lance, combining in this way Woma’s...

more
Issue 06/2011 Thixotropic grouting no more necessary

FDS air tube formwork of Pfeifer

As it is frequently not possible to fill the joints entirely with the plasticized mortar, the anticipated design resistance is lower in this case (Fig. 1). Competing systems even show larger...

more