Sika (Thailand) Limited confirms that Sikadur®-52TH is classified as non-toxic upon full curing (7 days) if instructions given in pertaining product data sheet and SDS are adhered to.
With regards to minimum age of concrete we would recommend 21 days in Thailand, because to our experience RMC attains the design compressive strength at this age.
Crack injection can be performed on all structural concrete.
The limitation is the maximum pressure applied during the injection process.
As a rule of thumb the following equation can be employed.