🧱 Concrete Mix Proportions – Strong vs Weak - Weak Column (1:6 – Cement:Sand) - Too much sand, too little cement. - Low binding strength → structure crumbles easily. - Short‑term savings, long‑term repair costs. - Cracked Column (1:2:2 – Cement:Sand:Gravel) - Common errors: excess water or missing gravel. - Water evaporation leaves voids → cracks form. - Reduced durability and unsafe load capacity. - Resistant Column (1:2:3 – Cement:Sand:Gravel) - Balanced mix: cement binds, sand fills gaps, gr