Considering the fact that Iran is one of the world's most seismically active countries, the use of lightweight concrete in constructions is reasonable which will reduce the seismic effective weight of the structures and therefore they will be less imposed to earthquake forces. So it is important to study about using lightweight concrete in construction in Iran. Considering the importance of the possibility of industrial production of light weight concrete, the cost effectiveness of design plays an important role in the approval or rejections of such plans. In this study the effect of the ratio of cement paste volume to the aggregate volume on the compression strength, density, viscosity and cost effectiveness of nine different mixture plans is studied. The cost effectiveness of the plans is adjusted by a cost factor based on the average price of materials. Due to the fact that the main goal of our examination is to observe the effects of the volume of binding materials in the plans under study, the water-cement ratio and type of cement (Portland 425-1) is kept constant while the total volume of the cement paste is varied and its effects on the factors noted above is studied. The aggregate materials of these designs include artificial aggregate (Lica) which are tested based on three different types of grading: 1-Light Coarse aggregate+s and 2-Light Fine aggregate+sand 3-Mixture of Coarse and Fine aggregate+sand.