How much weigh a shield?

Depends on the materials used and the level of shielding. When we speak of an armor level 3 in steels, it could weigh around 500 additional kilos for a pickup truck.
That same truck blast under the same conditions but using average market made with Kevlar and steel armour, could end up weighing around 380 kilos.
This same armor level 3 but in ultralight system 3D-Shield and with armoured glass ultralight would reduce his weight to about 280 kilos.
Therefore, we can conclude:
Level 3 in steel armor: = approx. 500 Kilos.
Level 3 in Kevlar armor + steel: = 380 kg Aprox.
Armor level 3 in 3D-Shield: = approx 280 Kilos.