What is Alkali-Aggregate Reaction (AAR). Alkali-aggregate reaction (AAR) is a chemical reaction between the alkali in Portland cement and reactive minerals in aggregate and additives that takes place when moisture is present.herefore with aggregates falling in deleterious zone, Use of low alkali cement is recommended to prevent any chances of ASR occurrence. 1  Alkali-silica, a reaction between the alkali hydroxides in concrete and reactive forms of silica in aggregate (e.g., chert, quartzite, opal, strained quartz crystals); 2  Alkali-silicate, a reaction between the ....
For solid hardwood flooring, both unfinished and prefinished, acclimation is a must. The same thing for laminate flooring. Keep it in the house for at least 48 hours prior to installation. The negative effects of not acclimating your hardwood floors before installation can be either buckling or gaps between the boards.
What the wood needs is acclimation, and it is the process of getting your new floors used to the conditions inside your house (temperature and humidity). Depending on the type of flooring the acclimation time can vary between 48 and 96 hours. This is an important step in the flooring installation process. There are flooring products which donât need to acclimate. Examples are tile, carpet and some engineered hardwood.