Search results
Results from the WOW.Com Content Network
A fairly well-defined reaction front can often be observed in thin sections; ahead of the front the concrete is normal, or near normal. Behind the reaction front, the composition and the microstructure of concrete are modified. These changes may vary in type or severity but commonly include: Extensive cracking; Expansion
The curing of concrete when it continues to harden after its initial setting and progressively develops its mechanical strength is a critical phase to avoid unwanted cracks in concrete. Depending on the temperature (summer or winter conditions) and thus on the cement hydration kinetics controlling the setting and hardening rate of concrete ...
48-metre (157 ft) slab between the fifth and the sixth piers collapsed Structural failure was caused by improper welding of the steel trusses of the suspension structure beneath the concrete slab roadway. Kobe Route of the Hanshin Expressway: Kobe, Japan: Japan 17 January 1995: Elevated highway Earthquake - support piers failed 0 killed. 0 injured
Reinforced autoclaved aerated concrete (RAAC) is a lightweight form of concrete that was used in schools, colleges and other building construction from the 1950s until the mid-1990s, according to ...
When a reinforced concrete member is put in tension, after cracking, the member elongates by widening of cracks and by formation of new cracks. Figure 1 Formation of internal cracks. Ignoring the small elastic strain in the concrete between the cracks, we can relate the crack width to the strain of the member by:
The mechanical stresses induced by the thermal cycles create micro-cracks in the concrete matrix and so facilitate the accessibility to water of the reactive mineral phases in the treated samples. [48] The concrete microbar test was proposed by Grattan-Bellew et al. (2003) as a universal accelerated test for alkali-aggregate reaction. [49]
Fiber-reinforced normal concrete is mostly used for on-ground floors and pavements, but can also be considered for a wide range of construction parts (beams, pillars, foundations, etc.), either alone or with hand-tied rebars. Concrete reinforced with fibers (which are usually steel, glass, plastic fibers) or cellulose polymer fiber is less ...
AOL latest headlines, entertainment, sports, articles for business, health and world news.