10KG RDP and 20KG RDP difference is in the pullout force, PVA can improve the initial adhesion, it has a certain viscosity, such as your 10 kg RDP can be replaced with 2 kg PVA with 8 kg RDP, 20 kg RDP content is no need to add PVA.
10 kg and 20 kg, the construction of the difference will not be too obvious, the more RDP content, tile adhesive'anti-slip more difficult to solve. the other is RDP content usually 15KG for C1, and then optimize the formula.
PVA generally do not have to add, water resistance is no effect, and the cost is not low, PVA is generally used in the low-end products without RDP