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.
A batch of wood floor is delivered to the home with proper 6 to 9 % MC inside a house with taping, mudding and painting on site. The manufacture recommends a minimum 1 week acclimation period prior to installation. 1 week later, the installer shows up to install the hardwood. 24 hours before the open house for potential home buyers, the builder notices large gaps in his hardwood floors. The Reason. You are acclimating your floor in the environment in which the RH is quite much higher than normal living condition.