Is it possible to use aluminum rods as reinforcement, for example to reduce weight?
It is possible, but in general it is not advisable. Aluminum reinforcement is sometimes used for special structures where, for example, it is necessary to avoid the magnetic influence of steel. Aluminum has much less bonding strength with concrete than steel, and loss of bond also takes place more suddenly. Concrete in contact with aluminum may also be porous due to a chemical reaction leading to gas evolution.