The document discusses how the gel/space ratio affects the strength of concrete. The gel/space ratio is the ratio of solid hydration products to available space in the concrete. A higher gel/space ratio reduces porosity and increases strength, while a higher water/cement ratio decreases the gel/space ratio, increases porosity and decreases strength. Power's experiment showed concrete strength has a specific relationship to the gel/space ratio.

1. Gel/Space Ratio
1. Since concrete is a brittle material, its porosity primarily governs
its strength. The compressive strength is found to be severely
decreasingwith increase in the porosity.
2. The porosity of concrete which governs the strength of concrete is affected
by the gel/space ratio inconcrete.
3. The gel/space ratio is the ratio of the solid products of hydration to the space
available for these hydration products.
4. A higher gel/space ratio reduces the porosity and therefore increases
the strength ofconcrete.
5. The gel/space ratio, which governs the porosity of concrete
affecting its strength, is affected by the water/cement ratio of
concrete.
6. A higher water/cement ratio decreases the gel/space ratio
increasing the porosity thereby decreases the strength of
concrete.

2. Gel/Space Ratio
1. Power’s experiment showed that the strength of concrete bears a specific
relationship with the gel/spaceratio.
2. He found the relationship to be 240 𝑥3, where x is the gel/space ratio and 240
represents the intrinsic strength of the gel in MPa for the type of cement
and specimenused.

3. Gel/SpaceRatio
Graph of Power’s experiment