A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement: SF:NP in the cementitious blend composition lies in the range of (24-63):(5-44):(32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water to the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

A cementitious blend composition and a concrete mix composition preferable for making concrete resistant to high temperatures and alkaline conditions, particularly for making durable concrete for constructing an alumina digester tank in an aluminum smelter. The cementitious blend composition includes at least one hydraulic cement, silica fume (SF), and natural pozzolan (NP), wherein a weight percent ratio of at least one hydraulic cement: SF:NP in the cementitious blend composition lies in the range of (24-63): (5-44): (32-40) with the sum of the weight percentages of the at least one hydraulic cement, the SF, and the NP not exceeding 100%. The concrete mix composition comprises water and the cementitious blend composition, wherein a weight ratio of the water the cementitious blend composition is 0.2-0.5, and wherein the concrete mix composition has a content of the cementitious blend composition of 400-550 kg/m.sup.3.

The present invention relates to a solution reaction apparatus and solution reaction method using the same, and more particularly a solution reaction apparatus and a solution reaction method using the same, wherein a reaction vessel is made by using a sealing member, a reaction vessel forming member, and a substrate serving as the bottom part of the reaction vessel so as to cause one side of a reaction solution only to contact the solution, thereby adjusting the temperature of the substrate differently from the temperature of the solution. The solution reaction apparatus of the present invention can control temperature of the substrate and temperature of the reaction solution separately, thereby it can control the temperature of the solution above the boiling point of the solution, and can react the solution while constantly maintaining the concentration of the solution by the solution circulatory device. Accordingly, it has an effect of freely forming various nanostructures on the substrate.