2024 · Q15
The surface of the concrete structure of a new construction is covered with straw/gunny bags by wetting. This is done to :
General KnowledgeChemistry
- Aprevent fast evaporation, until hydration has proceeded well
- Bprotect the concrete structure from contamination by dust particles
- Cprevent development of any fungus on the surface
- Dgive smoother and cleaner surface over cement structure
Explanation
Covering freshly laid concrete with wet straw or gunny bags is the curing process. Concrete gains strength through hydration, the chemical reaction of cement with water, which needs continuous moisture over several days. If the surface dried quickly by evaporation, hydration would stop prematurely and the concrete would be weak and cracked. Wet coverings keep the surface moist so hydration proceeds well. Hence option A is correct.