What is one effect of increasing the water-cement (W/C) ratio?

Increasing the water-cement (W/C) ratio has a significant effect on the strength and durability of concrete. When the W/C ratio is increased, the amount of water relative to cement also increases, leading to a higher porosity in the resulting concrete. This increased porosity contributes to a weaker concrete mix because the extra water creates voids and reduces the overall density of the concrete once it hardens.

With more water, the cement particles have more space between them, meaning the hydration process is less effective, and not all the cement can bond optimally. Consequently, the increased water content compromises the concrete's compressive strength, leading to weakened structural integrity. Lower strength correlates directly with an increase in the W/C ratio because the optimal ratio for achieving maximum strength is typically around 0.4 to 0.5 for most applications.

Understanding the relationship between the W/C ratio and the material properties is crucial for civil engineers when designing mixtures that need to meet specific strength requirements for various structural applications.