Ingeniería Civil y Mecánica
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Item Análisis de la resistencia a compresión del hormigón simple con agregado grueso reciclado y craqueo catalítico fluidizado en reemplazo del agregado fino(Ingeniería Civil y Mecánica. Carrera Ingeniería Civil, 2025) Espinoza Castro María José; Navarro Peñaherrera Carlos PatricioThis experimental study evaluates the compressive strength of plain concrete by incorporating recycled coarse aggregate (RCA) and spent fluid catalytic cracking (FCC) catalyst as a replacement for fine aggregate. This research responds to the growing need to promote sustainable practices in construction, optimize resources, and reduce the environmental impact generated by the extensive use of natural materials. The methodology was developed in three phases: characterization of the physical and mechanical properties of recycled aggregates, comparison of the compressive strength of traditional concrete versus concrete with RCA and FCC, and an analysis of economic feasibility. Concrete mixtures with 100% recycled materials and 100% natural aggregates were prepared following regulatory techniques such as NTE INEN and ASTM and were evaluated using standardized tests. The results show that the use of RCA and FCC affects the workability and strength of concrete, but within acceptable ranges for certain structural uses. After 7 days, the concrete with natural aggregates reached a strength of 171.45 kg/cm², while the mix with recycled aggregates reached 37.75 kg/cm². After 14 days, the strengths were 196.55 kg/cm² and 47.47 kg/cm², respectively, and after 28 days, values of 239.74 kg/cm² were obtained for natural aggregates and 74.17 kg/cm² for recycled aggregates. These figures show that, although there is an approximately 70% decrease in the strength of recycled concrete compared to conventional concrete, it can meet structural parameters for certain non-critical applications. Furthermore, the use of recycled materials is considered not to significantly reduce the cost of concrete: the cost per cubic meter increased from $100.90 (traditional mix) to $291.77 (mix with recycled materials), which represents a significant contribution in economic terms. The study's conclusions indicate that incorporating AGR and FCC is not feasible from a technical or economic perspective, even if the proportions in the mix are optimized or the project's structural requirements are considered. However, for other uses, this approach contributes to reducing environmental impact, fosters the circular economy, and promotes responsible resource use in the construction sectorItem Análisis de resistencia a la compresión en columnas de hormigón armado elaborado con materiales reciclados(Ingeniería Civil y Mecánica. Carrera Ingeniería Civil, 2025) Matías Sebastian Shambi Ortiz; Wilson Santiago Medina RobalinoThis experimental study aimed to evaluate the structural behavior of reinforced concrete columns incorporating recycled materials, specifically by partially replacing fine aggregate with 5% spent fluid catalytic cracking catalyst (FCC) and coarse aggregate with 20% recycled coarse aggregate (RCA). The performance of these columns was then compared to columns made with conventional aggregates. A quantitative approach was developed through three main phases: physical characterization of the materials (sand, gravel, RCA, and FCC), design and fabrication of reinforced concrete columns with three types of mixtures (conventional, with RCA, and with FCC), and compression testing of the columns. The specimens were designed as columns measuring 15×15×100 cm, reinforced with four longitudinal steel bars of 7 mm diameter and 4 mm stirrups. The design considered the 20-ton capacity limit of the testing machine under axial compression. The characterization results indicated that the natural aggregates met normative requirements, whereas the RCA showed a lower density (2241.99 kg/m³) and higher water absorption (2.64%), attributed to its porosity. The FCC also presented high porosity but with acceptable particle size distribution. To ensure the quality of the concrete, control cylinders were prepared and tested at 7 and 28 days. These samples reached an average compressive strength of 252.74 kg/cm², within the expected experimental margin (±5%) for a target design strength of 240 kg/cm². The nominal axial strength of the designed column section was calculated at 53.37 Tn, with a design strength of 27.30 Tn, indicating that failure would not occur during testing due to equipment limitations. Under testing, the maximum load applied by the compression machine was 20 Tn. The measured strain values were 0.005 mm/mm for the natural aggregate columns, 0.003 mm/mm for those with 5% FCC, and 0.002 mm/mm for those with 20% RCA. These results show reduced ductility for the recycled material columns, as lower strain corresponds to more brittle behavior. It was concluded that the incorporation of FCC and RCA tends to reduce ductility despite increasing strain capacity. Therefore, further research using more robust testing equipment is recommended to validate the feasibility of applying recycled aggregates in reinforced concrete columns with greater reliability