Ultra-high-performance concrete (UHPC) results from the mixture of several constituents, leading to a highly complex material in both, fresh and hardened state. The higher number of constituents, together with a higher number of possible combinations, relative proportioning and characteristics, makes the behavior of this type of concrete more difficult to predict. The objective of the research is to build four analytical models, based on artificial neural networks (ANN), to predict the 1-day, 7-day, and 28-day compressive strengths and slump flow. Recycled glass powder milled to different particle size, fluid catalytic cracking residue (FCC) and different particle size limestone powder was used as partial replacements for Portland cement and silica fume. The ANN models predicted the 1-day, 7day, and 28-day compressive strengths and slump flow of the test set with prediction error values (RMSE) of 2.400 MPa, 2.638 MPa, 2.064 MPa and 7.245 mm respectively. The results indicated that the developed ANN models are an efficient tool for predicting the slump flow and compressive strengths of UHPC while incorporating silica fume, limestone powder, recycled glass powder and FCC.

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In this study, the resistance of blended concrete containing catalytic cracking residue (FCC) to chloride ion penetration and carbonation was examined. FCC was added at the levels of 10%, 20%, and 30% as partial replacement for cement. Concretes with 10% of silica fume (SF), 10% of metakaolin (MK), and without additives were evaluated as reference materials. The rapid chloride permeability test (RCPT) performed according to ASTM C1202 standards and an accelerated carbonation test in a climatic chamber under controlled conditions (23 °C, 60% RH and 4.0% CO2), were used in order to evaluate the performance of these concretes. Additionally, their compressive strength was determined. The results indicate that binary blends with 10% FCC had similar compressive strength to concrete without additives and had lower chloride permeability. 10% SF and 10% MK exhibited better mechanical behavior and a significant decrease in chloride penetration when compared to 10% FCC. It is noted that there was an increase in concrete carbonation when FCC or MK were used as additives. It was also observed that with longer curing time, the samples with and without additives, presented higher resistance to carbonation. The accelerated corrosion test by impressed voltage was also performed to verify the findings and to investigate the characteristics of corrosion using a 3.5% NaCl solution as electrolyte. The mixtures that contained 10% FCC were highly resistant to chloride ion penetration and did not present cracking within the testing period.Keywords: fluid catalytic cracking, metakaolin, silica fume, pozzolanic additions, blended concrete, carbonation resistance, chloride ion penetration. RESUMENSe estudió la resistencia a la penetración del ión cloruro y a la carbonatación de concretos adicionados, con un residuo de catalizador de craqueo catalítico (FCC). El FCC fue adicionado en proporciones de 10%, 20% y 30%; como reemplazo parcial del cemento. Se evaluaron concretos como referencia con 10% de humo de sílice (HS), 10% de metacaolín (MK) y sin adición, así mismo, para evaluar el desempeño de estos concretos, se realizaron los ensayos de permeabilidad rápida a cloruros (PRC) de acuerdo con la norma ASTM C1202, y un ensayo de carbonatación acelerado bajo condiciones controladas (23 °C, 60% HR and 4.0% CO2). Adicionalmente, se determinó la resistencia a la compresión y de esta manera los resultados muestran que las mezclas binarias con 10% de FCC tuvieron una resistencia a la compresión, similar al concreto sin adición y más baja permeabilidad a los cloruros. Las mezclas con 10% HS y 10% MK, mostraron un mejor comportamiento mecánico y significativo, se evidenció menor penetración de cloruros comparado con FCC al 10%. Se observó también, un incremento en la carbonatación del concreto cuando se utilizó adición de FCC o MK y es claro que a mayor tiempo de curado, las muestras con y sin adición, presentan mayor resistencia a la carbonatación. El ensayo de corrosión acelerado por voltaje impreso, fue realizado para investigar y verif...

El objetivo principal de esta investigación es desarrollar una mezcla optimizada de concreto de polvos reactivos (RPC) que contenga materiales cementícios suplementarios (SCM), como la escoria siderúrgica de arco eléctrico (EASF) y el polvo de vidrio reciclado (RGP) entre otros, utilizando el diseño factorial. Se calcularon diferentes regresiones polinómicas para predecir con precisión las variables respuesta (flujo estático y resistencia a compresión a distintas edades) en función de los factores considerados. A través de un algoritmo multiobjetivo, se determinó la mezcla que alcance la resistencia y flujo estático adecuados con un contenido mínimo de cemento. La verificación experimental de esta optimización matemática mostró que con 621 kg/m3 de cemento ASTM Tipo HE, y un contenido máximo de 100 kg/m3 de humo de sílice, se puede alcanzar una resistencia a compresión superior a los 150 MPa en un concreto, además, autocompactante.

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Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.

Spent fluid catalytic cracking (FCC) catalyst is an oil industry by-product from fluidised-bed catalytic cracking units. This residue is mainly formed by an active component (faujasite type zeolite Y) in an amorphous aluminosilicate matrix. It mainly consists of up to 90% silica and alumina. This paper reports an extensive literature review regarding the characterisation and mechanical and durability properties of mortar and concrete added to this material. FCC has been studied lately due to its pozzolanic characteristics and the good performance of concrete mixtures using FCC as cement replacement.

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