Result of Quiz 14 "Two faces of one shower of kommórka concrete and prefabricated concrete"
Thank you for numerous applications in the ninth quiz of the Educationz Industry series under the slogan TWO FACES, ONE FUTURE OF CELLULAR CONCRETE AND PREFABRICATED CONCRETE.
Below we present the correct answers.
- Which type of cement should be used in the production of prefabricated prestressed bridge beams to obtain the guaranteed concrete strength (approx. 70-80% of the final strength) after approx. 20 hours from forming, so as to safely tension the element (cut the ropes): a) CEM I 52.5N SR3 / NA? or b) CEM III / B 42.5L-LH / SR / NA?
ANSWER: a) CEM I 52.5N SR3 / NA - because the use of this cement (95% Portland clinker content) allows for a safe achievement of early strength after approx. 20 hours in such a short time, while the use of CEM III / B cement 42.5L -LH / SR / NA does not guarantee obtaining this strength due to the high content of blast furnace slag (66-80%) in the cement composition in relation to clinker (20-34%).
- Why is aerated concrete a material with one of the lowest content of natural radiation among building materials?
ANSWER: Because its production uses natural raw materials with a low content of radioactive elements and the production process itself does not contain steps that increase the content of natural radiation.