Reinforced high-strength concrete can crack due to stresses that develop during the hardening process. However, this has been found to be surprisingly less quick than previously thought. Due to Dutch research, extra steps during the hardening process can be omitted. This will result in cheaper concrete.
Maya Sule from Delft University of Technology tested specimens of high strength concrete (concrete with little water) in a temperature stress testing machine (TSTM). Such tests indicate the progression of the stress development in the concrete specimens. They also predict the moment at which cracks will occur. Freshly poured concrete radiates heat during the hardening process and expands as a result of this. Upon cooling the concrete contracts again. If this so-called temperature contraction is prevented, for example due to the concrete being poured upon an existing foundation, cracks occur. As high strength concrete contains less water than normal concrete, the contraction is further increased due to the mix drying out on the inside.
The researchers assessed the nature of the crack formation by placing test specimens of non-reinforced high-strength concrete under tension. This led to a single through-crack. However, dependent on the reinforcement method used there were also some test specimens with shallow cracks which did not seriously weaken the test specimen. The non-reinforced test specimen with a single through-crack, completely cracked much more quickly than the reinforced test piece. In other words, reinforced high-strength concrete is less sensitive for cracks than non-reinforced high-strength concrete.
Nalinie Moerlie | alfa
Meter-sized single-crystal graphene growth becomes possible
22.08.2017 | Science China Press
Nagoya physicists resolve long-standing mystery of structure-less transition
21.08.2017 | Nagoya University
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences