Effect of lowering water–cement (w/c) ratio on concrete performance Decreasing the water–cement ratio, while maintaining adequate workability by proper mix design/admixtures, generally leads to which set of improvements?

Introduction / Context:
The water–cement ratio (w/c) is the dominant parameter governing the porosity of hardened cement paste. Lowering w/c produces a denser microstructure that benefits almost every durability-related property, provided the mix remains sufficiently workable for full compaction and proper curing is ensured.

Given Data / Assumptions:

• Workability maintained via optimized grading and admixtures, not by adding water.
• Proper consolidation and curing.
• Ordinary Portland or blended cements.

Concept / Approach:
Lower w/c reduces capillary pore volume, increasing density and decreasing permeability. Reduced permeability improves frost resistance by limiting freezable water and eases internal hydraulic pressures. Denser paste and stronger interfacial transition zones (ITZ) enhance abrasion resistance and bond to reinforcement. With better paste quality and reduced moisture gradients, creep and drying shrinkage tend to diminish as well (though aggregate stiffness and paste volume also play roles). Thus, a holistic improvement across multiple properties follows from controlled reduction in w/c.

Step-by-Step Solution:

Verification / Alternative check:
Durability indexes (e.g., rapid chloride permeability, sorptivity) and abrasion tests consistently show improvements as w/c decreases, when compaction and curing are adequate.

Why Other Options Are Wrong:

• Selecting only one benefit ignores that multiple properties improve in tandem as w/c is lowered.

Common Pitfalls:
Lowering w/c without providing workability through admixtures/gradation; inadequate curing that negates potential gains; assuming zero creep/shrinkage regardless of aggregate and paste volume.

Final Answer:
All of the above