Search results
Results From The WOW.Com Content Network
Concrete tests can measure the "plastic" (unhydrated) properties of concrete prior to, and during placement. As these properties affect the hardened compressive strength and durability of concrete (resistance to freeze-thaw), the properties of workability (slump/flow), temperature, density and age are monitored to ensure the production and ...
A w/c ratio higher than 0.60 is not acceptable as fresh concrete becomes "soup" [2] and leads to a higher porosity and to very poor quality hardened concrete as publicly stated by Prof. Gustave Magnel (1889-1955, Ghent University, Belgium) during an official address to American building contractors at the occasion of one of his visits in the ...
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.
Air entrainment is beneficial for the properties of both fresh and hardened concrete. [7] In fresh concrete, air entrainment improves workability and makes it easier to handle and pump. It also helps prevent bleeding and segregation, unwanted processes that can occur during mixing.
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.
Listed below are some basic mechanical properties of ECC, or Engineered Cementitious Composite, a specific formula of HPFRCC, developed at the University of Michigan. This information is available in Victor C. Li 's article on (ECC)- Tailored Composites through Micromechanical Modeling. [ 1 ]
Stamped concrete is an architectural concrete that has a superior surface finish. After a concrete floor has been laid, floor hardeners (can be pigmented) are impregnated on the surface and a mold that may be textured to replicate a stone / brick or even wood is stamped on to give an attractive textured surface finish.
On the other hand, for completely dry concrete, the chemical reaction of carbonation cannot occur. Another influencing factor for CO 2 diffusion rate is concrete porosity. Concrete obtained with higher w/c ratio or obtained with an incorrect curing process presents higher porosity at hardened state, and is therefore subjected to a higher ...