Final answer:
The negative effects of a high water to cement (w/c) ratio are decreased concrete strength, increased porosity, and reduced durability, leading to potential damage from freeze-thaw cycles, chemical attack, and steel reinforcement corrosion.
Step-by-step explanation:
When discussing the negative effects of a high water to cement (w/c) ratio, we are often referring to the impact on the quality and durability of concrete. A high w/c ratio can lead to several disadvantages in the concrete mixture:
- Decreased strength: A higher w/c ratio means that there is more water than necessary to initiate the cement's hydration reaction, resulting in a less dense concrete with lower strength.
- Increased porosity: Excessive water leaves behind pores in the concrete as it evaporates. These pores make the concrete more permeable and less durable.
- Durability issues: A porous structure in concrete can lead to greater susceptibility to freeze-thaw cycles, chemical attack, and corrosion of embedded steel reinforcement over time.
It is therefore essential to balance the water and cement in concrete to ensure optimal strength and durability while avoiding the aforementioned negative effects.