Gst on transporation charges

I am a GST regd. dealer. I order sand and stone chips from a UR dealer and pays him by bank transfer. Next day he send me the goods by a lorry for which transporation charge is paid by me to the driver directly in cash. Now my questions are:-

1) What is the tax rate of these product which I have to pay in RCM basis. What is the HSN code of these items?

2) Will I pay the tax in RCM basis on transporitng charges? If so what will be the rate and SAC ?