Experimental study on compaction effects on the ballistic resistance of sandbags

An experimental study was conducted to find out the effects of compaction of sand on the ballistic resistance of the sandbag. The implementation of various sandbag fabrics, namely, polyethylene, polypropylene, polyvinylchloride and Twaron, was also investigated. The sandbags were tested under various configurations - uncompacted, manually compacted, vacuum compacted and pneumatically compacted by inserting an inflatable airbag into the sandbag. Depending on their fabric strength, the sandbags were pneumatically compacted or pressurized up to different inflation pressures. Burlap, polyethylene and polypropylene sandbags were tested at 0.5 bar and polyvinyl sandbags at 0.5 and 1.0 bars while Twaron sandbags were tested at 0.5, 1.0 and 2.0 bars. All sandbag specimens were subjected to ballistic impact by a spherical steel projectile. The increase in inflation pressure led to the rise in shear resistance of the sand through compaction and the rise in fabric pretension as well, resulting in better ballistic resistances (higher ballistic limit and energy absorbed) of the sandbag specimens. With the aid of inflatable airbags, it is possible for sandbags of less expensive and lower strength fabrics to exceed the ballistic resistances of uncompacted and manually compacted high performance Twaron sandbags.