A vízzáró vasbeton szerkezetek készítésekor figyelembe kell venni, hogy a képlékeny vagy folyós konzisztenciájú keverékekből készített friss, bedolgozott beton – még gondos tömörítés után is – hajlamos zsugorodásra, és az emiatt keletkezett repedések csökkentik a vízzáróságot. Ez a hatás megszüntethető a bedolgozott beton pihentetés utáni újravibrálásával.

http://aktivitas-tiszk.hu/elearning/Kereszturi_Hajnalka/beto...

CURING TIME FOR CONCRETE
In standard industrial cases, full strength concrete is recognized at 28 days. At seven days, you should have concrete that is cured to 70% full strength or greater. But to answer the question of, “How long does concrete take to set?” concrete setting time is generally 24 to 48 hours. At this point the neighborhood dog will not leave his footprints in it, but you should keep it clear of heavy equipment during this time period. Most mixes are cured at 28 days.


Hőérlelés

The Concrete Maturity Method and Calculating Concrete Strength

In addition to cube manufacture, the strength of concrete can also be monitored in situ using thermal maturity monitoring. This involves the placement of temperature monitoring loggers in the concrete at key points to measure the temperature as the concrete hydrates. This data can detect problems with concrete curing and also warn of thermal issues in both hot and cold conditions. It can also be used to measure temperature differential between ambient and surface to prevent thermal cracking when striking formwork. Concrete maturity is calculated using the Sadgrove equation. Sadgrove first came up with the idea of concrete ‘equivalent age’ in 1971, and this method has been tried and tested before. It is a standard practice according to ASTM C1074.
https://help.converge.io/hc/en-us/articles/115000782751-The-...

3. oldal: periodically record the temperatre of the concrete as it cures
https://www.flir.eu/globalassets/discover/instruments/concre...

Amíg megköt:
https://www.becosan.com/how-long-concrete-take-set/#How_long...


Az se mindegy, hogy milyen beton...


TYPES OF CONCRETE
The most common types of concrete are:

High Strength Concrete: the most basic and important property of concrete is its compressive strength. Concrete with a compressive strength of 40Mpa (5,800 psi) is called high strength concrete.

High Performance Concrete: is a new term for some concretes being developed today. It is a fairly broad term that describes concretes that outperform "normal", everyday concrete in one or more characteristics such as lifespan, lifespan in corrosive environments, permeability, density, ease of placement, or many other parameters.

Lightweight Concrete: is made by using small, lightweight aggregates, such as small balls of styrofoam (thermocole) or by adding foaming agents to the mix of concrete. Lightweight concretes have low structural strength, and are used mostly in non-structural elements. The best is example is aerated autoclaved concrete (AAC) blocks used for making walls. Also called cellular concrete or aerated concrete.

Self Consolidating Concrete, also called Self Compacting Concrete:

Sprayed Concrete or Shotcrete: you can actually spray concrete onto a surface to form a thick, uneven coating. This process is different from other concreting methods in that the concrete is not poured into a form or mould. It is sprayed directly onto a surface, and is used in infrastructure projects and to repair old, cracked concrete surfaces. Shotcreting is also called guniting.

Water-resistant Concrete: normal concretes are permeable to water; that is, they allow water to pass through. Water resistant concretes are engineered to have fine particle cement replacements that do not allow water to pass through. These are very useful for construction below ground, like basements, as well as water retaining structures like water tanks and dams, and of course marine structures like jetties and bridges.

Micro reinforced concretes: are a new generation of high-tech concretes. They contain small steel, fibreglass or plastic fibres that dramatically alter the properties of concrete.

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Note added at 1 hr (2019-11-08 13:39:38 GMT)
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http://www.understandconstruction.com/concrete.html