The Ca-based solidification material has neutrality so that it would be expected to be new material to reduce environmental load instead of cement in the construction field. The concrete using this material, which is Ca concrete, is useful for construction material from past research. In previous researches, we showed that the compressive strength of Ca concrete and the compressive strength of AE concrete, which contains the entrained air, had nearly equal strength under same mixture condition, and the behavior under compression loading of Ca concrete showed a tendency similar to cement concrete. Also, the compressive strength of Ca concrete obtained the stable strength when it had the curing for four weeks. Therefore, Ca concrete would be used in the same way as cement concrete for construction field. This study investigates to consider further properties of Ca concrete. Particularly, it is paid attention to the water absorbability, water retentivity, and the compressive strength under natural environment. As a result, it is clear that the Ca concrete has the higher water absorbability and the water retentivity as compared with cement concrete and the compressive strength of Ca concrete under natural exposure does not decrease even if the length of natural exposure passes for 104 weeks. Hence, the Ca concrete would apply to construction material under natural environment as one of the measures against urban heat island phenomenon.