Reinforced concrete structural repairs

Τίτλος

Reinforced concrete structural repairs

Θέμα

Reinforced concrete

Building materials

Δημιουργός

Passades, Anna

Πηγή

Higher Technical Institute

Το πλήρες κείμενο είναι διαθέσιμο από το Υπουργείο Ενέργειας, Εμπορίου Βιομηχανίας και Τουρισμού.

Εκδότης

Library of Cyprus University of Technology

Ημερομηνία

1990

Δικαιώματα

Απαγορεύεται η δημοσίευση ή αναπαραγωγή, ηλεκτρονική ή άλλη χωρίς τη γραπτή συγκατάθεση του δημιουργού και κάτοχου των πνευματικών δικαιωμάτων.

Μορφή

pdf

Γλώσσα

eng

Τύπος

text

Αναγνωριστικό

CED0069

Σύνοψη

Ever SInce portland cement was invented in 1824, the use of concrete has expended steadily. Today it is by far the most important building material of all, easy to produce handle, and shape; concrete is also very durable if construction is carried out property. The lime Ca(OH) 2, given off during hydratIon of the cement helps protect the reinforcing against rust.
The sharp increase in the consumption of fossil fuels over the last few decades has produced a level of pollutIon that is damaging not only our irreplaceable forests, but our buildIngs as well. The amount of acidIc pollutants, chiefly sulfur dioxide (S02), carbon dioxide (NO x ), released to the atmosphere by combustion has doubled In tIle past 20 years.
the carbonic and sulfuric acids produced when they come into contact wIth mOIsture In the air attack steel. stone, concrete. and many other materials even more Intensively. CO2 and S02 in the atmosphere react with the lime of the cement to form carbonates and gypsum, WhICh steadIly reduces the concrete1s alkalinity. When the pH falls below 9.5 the passivation effect that keeps the steel from corroding is lost. The speed with which this carbonation takes place depends on two factors, the acid concentratIon and the quality of the concrete (cement content, density, strength) when the carbonation reaches the reinforCIng steel, the steel starts to rust. The resulting increase in volume generates extreme pressure that eventually cracks and spalls the concrete. concrete damage can often be traced to other causes however.
some of the more common ones are faulty planning, errors in
production of the concrete, insufficlent coverage of the
reinforcing steel, extreme weather conditions, and attack
by thawing salts.