The evolution rule of immersion time on the concrete moisture content was investigated. The compressive and splitting tensile strengths of concrete under five different humidity conditions were observed with five different loading rates of compressive and splitting tensile strengths. From the analysis of the test data, predictive equations that relate the compressive and splitting tensile strengths to the loading rates were formulated. The effects of loading rates were identified and separated from those of the moisture content. The experimental results indicate that at the same loading rate, both the compressive strength and the splitting tensile strength decrease with increasing moisture content. However, for the same moisture content, they exponentially increase with increasing loading rates. Thus, when the loading rates grow at the same rate, the splitting tensile strength considerably increases compared with the compressive strength.