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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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13This study evaluated the influence of partial replacement of Portland cement by rice 14 husk ash (RHA) to enable the use of green coconut husk fiber as reinforcement for 15 cementitious matrix. The use of highly reactive pozzolanic ash contributes for 16 decreasing the alkaline attack on the vegetable fiber, originated from waste materials. 17The slurry dewatering technique was used for dispersion of the raw materials in aqueous 18 solution, followed by vacuum drainage of water and pressing for the production of pad 19 composites, as a simplified simulation of the Hatschek process for industrial 20 manufacture. Five formulations were evaluated, two of them without any mineral 21 additions. One of the mixtures served as a reference (without green coconut fibers) and 22 the remaining ones were reinforced with the green coconut fibers (5% by weight of 23 binder) and with the content of Portland cement replacement by RHA equal to 0, 30, 40 24 and 50%. The composites were analyzed at 28 days of age and after ageing by 25 immersion in warm water (65°C), which lasted for 28 additional days. Physical and 26 mechanical tests were applied for assessment of the performance of composites. 27Thermogravimetric analysis was used to observe the consumption of portlandite and 28 chemically combined water content in the hydrated products for pastes presenting the 29 same levels of Portland cement replacement by RHA (i.e., 0-50%) and with the 30 water/binder ratio kept constant and equal to 0.5. The mechanical performance 1 evaluated by bending test after 28 days reached the MOR of 15.7 MPa after the 1 accelerate ageing, for the composites reinforced with the green coconut fiber and with 2 high levels of Portland cement replacement by RHA demonstrating that the use of green 3 coconut fiber for reinforcement can be very promising for the production of binary 4 cement based matrix. The thermogravimetry showed that the replacement of Portland 5 cement by the RHA helped in maintaining the mechanical behavior of the green coconut 6 fiber in the composite subjected to the accelerated ageing tests, and resulted in improved 7 mechanical performance, providing a lightweight composite. 8 9

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.

Ceramic materials represent around 45% of construction and demolition waste, and originate not only from the building process, but also as rejected bricks and tiles from industry. Despite the fact that these wastes are mostly used as road sub-base or construction backfill materials, they can also be employed as supplementary cementitious materials, or even as raw material for alkali-activated binders. This research aimed to investigate the properties and microstructure of alkali-activated cement pastes and mortars produced from ceramic waste materials of various origins. Sodium hydroxide and sodium silicate were used to prepare the activating solution.The compressive strength of the developed mortars ranged between 22 and 41 MPa after 7 days of curing at 65ºC, depending on the sodium concentration in the solution and the water/binder ratio. These results demonstrate the possibility of using alkali-activated ceramic materials in building applications.