Fly ash and silica fume are industrial by-products with pozzolanic properties.Therefore, they can be largely used in combination with lime to produce cementitious pastes so as to reduce the consumption of raw materials,energy, and the CO2 emission during the cement production.This study explored the compressive strengths of the lime-pozzolana pastes produced by high calcium hydrated lime, type F fly ash and silica fume.The water-binder ratio and curing conditions were varied, and the total pozzolana content was limited by 40% by weight.Results showed that the compressive strengths were increased by the decreased water-binder ratio and the early strengths were substantially increased by the addition of silica fume and water curing during the early ages.However, the specimens were unstable in water and lost some strengths between ages of 28-90 days if continuously wetted.In contrast, specimens exposed to air after the initial water curing of 28 days continued to gain strengths up to 32.6 MPa.Some researches in literature have shown that, when lime is wetted, its crystal structure undergoes changes and has negative impacts on the physical properties of the lime.Therefore, this study presumes that the pre-soaking lime in water can allow these changes to take place before the paste is made,thereby mitigating the negative effects on strength developments.Further investigations were conducted on the strength gains of the ternary pastes made with natural lime, or lime pre-soaked in water for 14 days before use.Two different paste mix proportions with varying amounts of lime were investigated at a water-binder ratio of 0.35 and cured in saturated lime water at 25 ℃ until the time of test.Results showed that the strengths of the pastes made by pre-soaking lime were continuously increased.In summary, the lime-pozzolana paste is a promising binder, which can be used in the absence of the Portland cement.With proper mix proportions, curing regimes, and high strength-to-weight ratios, the lime-pozzolana pastes are expected to reduce the weight and the overall cost of the structures.