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Fresh cement water has a pH of about 13.5 while evolved cement water pH ~ 12.5 is controlled by the dissolution of calcium hydroxide (portlandite). Carbon dioxide present in the air slowly diffuses through the concrete cover over the rebar and progressively reacts with the alkaline hydroxides ( KOH , NaOH ) and with calcium hydroxide leading to ...
The durability design of reinforced concrete structures has been recently introduced in national and international regulations. It is required that structures are designed to preserve their characteristics during the service life, avoiding premature failure and the need of extraordinary maintenance and restoration works.
ACI Code 7.10.4.2: For cast-in-place construction, size of spirals shall not be less than 3/8 in. diameter. ACI Code 7.10.4.3: Clear spacing between spirals shall not exceed 3 in., nor be less than 1in. Section 10.9.3 adds an additional lower limit to the amount of spiral reinforcement via the volumetric spiral reinforcement ratio ρ s.
(2) The thermal expansion coefficients of concrete and steel are so close (1.0 × 10 −5 to 1.5 × 10 −5 for concrete and 1.2 × 10 −5 for steel) that the thermal stress-induced damage to the bond between the two components can be prevented. (3) Concrete can protect the embedded steel from corrosion and high-temperature induced softening.
In new satellite imagery, Russia's military appears to be packing up equipment at a key airbase in Syria. The images show transport aircraft ready to load cargo at the Hmeimim Air Base on Friday.
More Fermentation, Fewer (Tummy) Problems. Fermentation has long been praised for its benefits on gut health, and you're more likely to encounter these benefits when leaving the U.S. for more ...
WASHINGTON (Reuters) -A massive winter storm moving across the United States will not keep the U.S. Congress from meeting on Monday to formally certify Republican Donald Trump's election as ...
3 Code of Practices for plain and reinforced concrete etc. IS 456 – 2000 4 Methods of sampling and analysis of concrete IS 1199 – 1959 5 Recommended Guide Lines for Concrete Mix Design IS 10262 – 1982 (F) Curing Compound; 1 Standard test method for water retention & daylight reflection test on concrete. ASTM-C-156809