Incompetent people passing comments on what they know nothing about. How can someone say there is no time frame for construction after reclaiming a site? Some are talking about concrete mix, some talking about paints. This is the territory of Structural Engineers who have the capability to do hollistic investigation of what went wrong. By the way you can have very strong concrete mix but if the beams and columns were not properly connected you will still have a collapse inspite of your strong concrete mix.