Portland cement has been utilized in the protection of historical sites. However, this usage is always controversial due to the high strength of the cement, its poor compatibility, ease of forming crystal deposits and inability to respond to the historical value of the original buildings. Many early repairs have demonstrated these problems.However, Portland cement is still used in China as an effective reinforcement material for rocks that are in danger of falling and breaking.Unfortunately, there is little research on the use and the possible problems of such mortar as applied for conservation purposes. For this reason, in this paper, the workability, mechanical properties and durability of different types of Portland cement and Portland cement with different additives were studied. The results revealed that organo silicones could control the ion release without affecting the workability and strength of the mortar. The strength, resistance to ion release and waterproofing properties of super fine cement are better than for common cement, although its rate of SO2-₄ ion release is 2 to 5 times higher than that for common cement, because the super fine cement contains more CaSO₄ than common cement does. For practical applications, it is suggested using super fine cement with low CaSO₄ and adding organo silicone.