What is the meaning of the defect liability period?
Particulars OPC PPC Name Ordinary Portland Cement Portland Pozzolana Cement IS Codes OPC 33 Grade Cement is IS: 269, for 43 Grade Cement IS: 8112 is used and for 53 Grade Cement IS: 12269 PPC IS 1489 (part 1 & 2) 1991 Ingredients & Manufacturing process Cement is made by heating limestone (CRead more
| Particulars | OPC | PPC |
| Name | Ordinary Portland Cement | Portland Pozzolana Cement |
| IS Codes | OPC 33 Grade Cement is IS: 269, for 43 Grade Cement IS: 8112 is used and for 53 Grade Cement IS: 12269 | PPC IS 1489 (part 1 & 2) 1991 |
| Ingredients & Manufacturing process | Cement is made by heating limestone (CaCO3 & clay) to 1450oC in a kiln & grounded with gypsum. | Pozzolana materials like fly ash, volcanic ash are blended to OPC @ 15%-35% by wt. |
| Environmental impact | Uses limestone clay & gypsum which are natural stones & emits CO2 during making. | Consumes industrial wastes such as fly ash, bf slag, etc. & is environment friendly. |
| Grades available | 33, 43, 53 Grades | Don’t have any grade but attains strength of 33 grade cement on 228 days curing. After that its strength gain slows down. |
| Cost per unit | Costly compared to PPC due to limestone | Cheaper bcoz limestone replaced by pozzolana |
| Sulphate resistance | Less durable in aggressive weather & sulphate attack & hence not preferred for marine structures, hydraulic structures, sewages pipes, etc. | Highly resistant to sulphate & used & preferred for marine structures, hydraulic structures, sewages pipes, etc. |
| Permeability & Durability | Low fineness, permeability is less | Higher fineness, higher permeability, result high durability. |
| Setting time | Initial setting time: 30mins
Final setting time: 280mins |
Initial setting time: 30mins
Final setting time: 600mins |
| Construction speed | Faster construction speed as it gains strength early. | Gains strength with time. |
| Fineness | OPC has finiteness of 225 sq.m/kg. It has lower fineness than PPC. So, it has higher permeability resulting lower durability. | PPC has finiteness of 300 sq.m/kg. It has higher fineness than OPC. So, it has lower permeability resulting in higher durability. |
| Heat of Hydration | It contains active salt hence more Heat of Hydration. Don’t have blended material & it gains 95% early strength in 7 days. | Blended cement with flyash or slag, etc. Low heat of hydration. Gains 75% strength in 7 days & 90% strength in 14 days. |
| Shrinkage cracks | Will be more due to high heat of hyudration | Less shrinkage cracks |
| Workability | Lower | Lower |
| Mass concrete | Not preferred | Preferred for mass concreting |
See less
Emmyvin
Defect Liability period is a particular amount of time given to the contractor after the completion of a project to check if the project is delivered in good shape, whereby if any defects be detected, the contractor is to fix the defect for free during the defect liability period.
Defect Liability period is a particular amount of time given to the contractor after the completion of a project to check if the project is delivered in good shape, whereby if any defects be detected, the contractor is to fix the defect for free during the defect liability period.
See less