Wat is Geopolymeerbeton?
In geopolymeerbeton zit helemaal géén cement, maar een combinatie van ‘cementvervangende minerale stoffen’ afkomstig uit bekende industriële reststoffen als hoogovenslak en vliegas en ook uit natuurlijke bronnen zoals biomassa-assen of sedimenten als rivierslib.
Wat is HK cement?
Hoogovencement is een type cement met een andere samenstelling dan portlandcement; bij de klinker wordt hoogovenslak gemengd, een afvalproduct van de ijzerproductie in een hoogoven. Een dergelijk cement bevat uiteraard geen ijzerverbindingen meer.
What is alkali in concrete?
Aggregate containing feldspars, some micas, glassy rock and glass may release alkali in concrete. Sea dredged sand, if not properly washed, may contain sodium chloride which can contribute significant alkali to concrete. 3. Admixtures Admixture in the context of AAR in concrete means chemical agents added to concrete at the mixing stage.
How do aggregates react with alkali hydroxides in concrete?
However, some aggregates react with the alkali hydroxides in concrete, causing expansion and cracking over a period of many years. This alkali-aggregate reaction has two forms: alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR).
How common is alkali-silica reaction distress in concrete?
Although potentially reactive aggregates exist throughout North America, alkali-silica reaction distress in concrete is not that common because of the measures taken to control it. It is also important to note that not all ASR gel reactions produce destructive swelling. Alkali-carbonate reaction (ACR) is observed with certain dolomitic rocks.
How does cold weather affect the alkali content of concrete?
In the areas of cold weather, de-icing salt containing sodium compounds which may increase the alkali content on the surface layer of concrete. Soils containing alkali may also increase alkali content on the surface of concrete.