Search results
Results from the WOW.Com Content Network
When the C-S-H gel is exposed to atmospheric carbon dioxide, it undergoes a rapid carbonation, and white or yellow efflorescences appear at the surface of concrete. When the relatively fluid alkali gel continues to exude below the hardened superficial gel layer, it pushes the efflorescences out of the crack surface making them to appear in relief.
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 ...
Concrete creep is essentially the sagging of concrete over time. Creep and shrinkage of concrete are two physical properties of concrete.The creep of concrete, which originates from the calcium silicate hydrates (C-S-H) in the hardened Portland cement paste (which is the binder of mineral aggregates), is fundamentally different from the creep of metals and polymers.
The concrete is aerated and “bubbly”, contains no “coarse aggregate” and is less dense than traditional concrete, being around a third of the weight, according to a building consultancy.
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
Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2] Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. [3]
When water is added to cement, each of the compounds undergoes hydration and contributes to the final state of the concrete. [2] Only calcium silicates contribute to the strength. Tricalcium silicate is responsible for most of the early strength (first 7 days). [3] Dicalcium silicate, which reacts more slowly, only contributes to late strength.
A 1924 issue of Concrete magazine said that the operation at 1000 La Brea Ave. appeared to be "the pioneer mixing plant in the West," the first of its kind offering "ready-mixed Portland cement ...