This paper provides information about the synthesis and mechanical properties of geopolymers based on 12 fluid catalytic cracking catalyst residue (FCC). FCC was alkali activated with solutions containing 13 different SiO 2 /Na 2 O ratios. The microstructure and mechanical properties were analysed by using several 14 instrumental techniques. FCC geopolymers are mechanically stable, yielding compressive strength about 15 68MPa when mortars are cured at 65ºC during three days. The results confirm the viability of producing 16 geopolymers based on FCC.

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Reuse of industrial and agricultural wastes as supplementary cementitious materials (SCM) in concrete and mortar productions contribute to sustainable development. In this context, Fluid catalytic cracking catalyst residue (spent FCC), a byproduct from the petroleum industry and petrol refineries, have been studied as SCM in blended Portland cement in the last years. Nevertheless, others environmental friendly alternative has been conducted in order to produce alternative binders with low CO 2 emissions. The use of aluminosilicate materials in the production of Alkali-Activated Materials (AAM) is an ongoing research topic which can present low CO 2 emissions associated. Hence, this paper studies some variables that can influence the production of AAM based on spent FCC. Specifically, the influence of SiO 2 /Na 2 O molar ratio and the H 2 O/spent FCC mass ratio on the mechanical strength and microstructure are assessed.Some instrumental techniques, such as SEM, XRD, pH and electrical conductivity measurements, and MIP are performed in order to assess the microstructure of formed alkali-activated binder. Alkali activated mortars with compressive strength up to 80 MPa can be formed after curing for three days at 65 ºC. The research demonstrates the potential of spent FCC to produce alkali-activated cements and the importance of SiO 2 /Na 2 O molar ratio and the H 2 O/spent FCC mass ratio in optimising properties and microstructure.

A. Pereira; Akasaki, JL.; J.L.P.Melges; Mitsuuchi Tashima, M.; Soriano Martinez, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.... (2015). Effect of sugarcane bagasse ash (SBA) added to alkali-activated blast furnace salg (BFS) AbstractSugarcane bagasse is an agricultural waste which can be transformed, for cementing purposes, into an interesting material by combustion. Specifically, the ash (SBA) obtained by autocombustion was used for preparing alkali-activated cements by blending blast furnace slag (BFS). SBA had a large amount of quartz; however, it reacted in high alkaline medium. Mixtures of BFS/SBA have been used for preparing alkali-activated mortars, by using NaOH (8M solution), sodium silicate (8M solution in Na + and SiO 2 /Na 2 O molar ratio of 0.5) and KOH (8M solution) as activating reagents. Replacements of 25, 33 and 50% of BFS by SBA were carried out and compressive strengths in the range 16-51 MPa were obtained after 90 curing days. Microstructural studies demonstrated that the hydration products formed in the activation of BFS are not significantly affected by the presence of SBA in the mixture. The durability of alkaliactivated mortars was compared to ordinary Portland cement (OPC) mortar in the following media: hydrochloric acid, acetic acid, ammonium chloride, sodium sulphate and magnesium sulphate. The behaviour of alkali-activated mortars with BFS and BFS/SBA was better than that found for plain OPC mortars, especially in ammonium chloride, acetic acid and sodium sulphate media. After 200 days of testing in ammonium chloride solution, the compressive strength loss for Portland cement mortar was about 83.3%. For the same test conditions, alkali-activated mortars presented a maximum reduction of 48.4%. The presence of SBA in alkali-activated BFS mortars did not produce any serious problems in durability. As a general conclusion, sugarcane bagasse ash (SBA) obtained by autocombustion showed good cementing properties as a mineral precursor blended with blast furnace slag (BFS) in alkali-activated systems.

Blast furnace slag (BFS)/sugar cane bagasse ash (SCBA) blends were assessed for the production of alkali-activated pastes and mortars. SCBA was collected from a lagoon in which wastes from a sugar cane industry were poured. After previous dry and grinding processes, SCBA was chemically characterized: it had a large percentage of organic matter (ca. 25%). Solutions of sodium hydroxide and sodium silicate were used as activating reagents. Different BFS/SCBA mixtures were studied, replacing part of the BFS by SCBA from 0 to 40% by weight. The mechanical strength of mortar was measured, obtaining values about 60 MPa of compressive strength for BFS/SCBA systems after 270 days of curing at 20 °C. Also, microstructural properties were assessed by means of SEM, TGA, XRD, pH, electrical conductivity, FTIR spectroscopy and MIP. Results showed a good stability of matrices developed by means of alkali-activation. It was demonstrated that sugar cane bagasse ash is an interesting source for preparing alkali-activated binders.