The 2018 Structures Congress (Structures18) Songdo Convensia, Incheon, Korea, August 27 - 31, 2018 Strengths development of slag-based paste with CFBC fly ash under different curing conditions *Harry Hermawan 1) , Ta-Peng Chang 2) and Yu-Chen Wu 3) 1), 2), 3) Department of Civil and Construction Engineering, NTUST, Taipei 106, Taiwan 1) harzhermawan@yahoo.com, 2) tpchang@mail.ntust.edu.tw, 3) s880123456@gmail.com ABSTRACT The mechanical properties of hardened no-cement paste incorporated with utilization of circulating fluidized bed combustion (CFBC) fly ash, ground granulated blast furnace slag (GGBFS), and class F fly ash (FA) was investigated. The ratios of slag replacement by class F fly ash were 0, 0.2, and 0.5 with CFBC fly ash additions of 15% and 20% using water-to-binder ratio of 0.35. Curing conditions introduced as the specimens were cured at 20 °C, 30 °C, and 40 °C, respectively as initial curing condition, thus after 3 days, the specimens were subjected to the constant temperature of 20 °C. The result showed that curing in the high temperature tended to increase the strength and the addition of CFBC fly ash by 20% was chosen as the optimum amount to improve the compressive strength for later ages at higher temperature. 1. INTRODUCTION Consistently there have been many efforts from some researchers in the construction field due to the major concern over environmental problem related to global warming. Portland cement is the major problem due to the production in the large amount releases lot of carbon dioxide (CO 2 ) emissions. Thus, some researchers pay more attention to utilize the power plant residue such as fly ash owing to this residue can be classified as environmental-friendly material. Ground granulated blast furnace slag (S) and class F fly ash (F) were the most trendy pozzolanic material that can be used to partially replace ordinary Portland cement for the reason that these materials can improve the mechanical and durability properties of paste, mortar and/or concrete. Apparently, many researchers developed the recent waste material from the thermal power plant by using circulating fluidized bed combustion (CFBC) technology. This technology releases a lot of fly ashes that have good physicochemical properties. Reducing the SO 2 and NO x emissions is the main purpose of the application of the aforementioned method. The CFBC fly ash (C) mostly has the non-spherical form and contains high CaO and SO 3 content. When the CFBC fly ash dissolves with the water, 1), 3) Graduate Student 2) Professor