This research aims to study a compressive strength. (A state saturated with water and dried) to absorb water. And contraction of the soil with sand. And the ratio of the sand used in the production block. The variables used in the study was from the gravel and sand from Ayutthaya Province. Each of the ingredients to be replaced with sand aggregate 20.40 percent and 60 sample and incubated for 7, 14 and 28 days when the test showed that the soil has a high viscosity index and therefore should not be used. production block And the need for improving the soil with sand. The study indicated that When replacing the Gross sand in the percentage higher. As a result, the density of the block is likely to increase. Water absorption and contraction is declining. A compressive strength of a block of dry weather is likely to increase as the incubation period and the amount of sand being replaced. Each ratio has a compressive strength criteria by TIS. 57-2533 and TIS. 58-2533 (not less than 70 kg / cm 2), since the incubation period of seven days, the changing conditions. dry conditions saturated with water to make a compressive strength decreases. While developing a resistance increases as the incubation period. And the benchmark 28 days and found that the ratio of sand to produce the block by replacing sand ratio of 1: 5 with sand instead of 60 percent.