Spread the Cement. You will need about three to four pounds of Portland cement for each square foot of your soil cement surface . Use a bit less for soils with a lot of sand or gravel, and a bit more for soils with more clay or organic matter. Watch the videos and then let's start building with this material Which product is better—portland cement or hydrated lime—in stabilizing clay soils? In 2003, an investigation was completed that evaluated the performance of portland cement and hydrated lime in stabilization and in improving engineering properties of several soils. Three soils were examined that had Plasticity Index (PI) values of 25, 37, and 42. The following general conclusions can be drawn based upon the investigation performed: 1. For the soil with a PI of 25, portland cement performed better than lime even at dosages as low as 3 percent. For the soils with a PI of 37 and 42, the performance increased significantly when the cement dosage was increased to...