If you ever look closely、you might wonder where this rust comes from.I asked for many comments on this point.As a result, I had come to a conclusion that in this case the rain had soaked into the concrete block so that the reinforced concrete block inside got decayed and the rust flowed out. Since I had not yet seen such state of the concrete block before, it was thought at first that the decay might have come out along the reinforcement or maybe the joint happened to be weak and the decay came out from the joint.But however,if you know since the concrete block is actually quite dense inside the decay might have occurred naturally in the gap.
At any rate the treatment is urgently required.
