DSpace Angular :: Browsing by Author "Silva Urrego, Yimmy Fernando"

Browsing by Author "Silva Urrego, Yimmy Fernando"

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Adobe mixtures reinforced with fibrillated polypropylene fibers: Physical/mechanical/fracture/durability performance and its limits due to fiber clustering
(2022) Burbano Garcia, Claudia Patricia; Silva Urrego, Yimmy Fernando; Araya Letelier, Gerardo Andres
This study assesses the feasibility of the incorporation of fibrillated polypropylene fibers (FPFs), an engineere multidimensional and multifilament fiber mostly used to reinforce concrete mixtures, into adobe mixtures (AMs), a traditional and manually-made material used to produce adobe blocks. The incorporation of FPFs was assessed using increasing dosages (0%, 0.25%, 0.5%, and 1% in wt% of clay soil) of FPFs. These fibers were gradually added and mixed with the clayey soil prior to incorporation of water to promote uniform mixtures with adequate fiber distribution to reduce the formation of fiber clusters. The impact of FPFs was evaluated in terms of its effects on the bulk density (physical), compressive and flexural strength (mechanical), flexural toughness indices (fracture) and water erosion resistance (durability) of AMs. Results indicate that increasing dosages of FPFs monotonically reduce average values of bulk density, as well as compressive and flexural strength of AMs. On the other hand, these increasing dosages of FPFs monotonically increase average values of water erosion resistance as well as flexural toughness indices, varying the flexural failure mode from brittle (unreinforced AM) to ductile (reinforced AMs) because of the adequate bonding and FPF-bridging effect after the crack generation as confirmed by instrumentation as well as digital image correlation evaluations implemented in this study. The significant reductions of bulk densities and compressive and flexural strengths obtained for fiber-reinforced AMs were related to the increasing number of fiber clusters found for increasing dosages of FPFs within the fiberreinforced mixtures, which was evaluated using scanning electron microscopy analyses. For example, positively the AM incorporating 1% of FPFs increased, on average, the flexural toughness by 674% and reduced the bulk density and water erosion depth by, on average, 9% and 64%, respectively, when compared to the unreinforced AM. However, this large dosage of FPFs also generated a significant reduction of the compressive strength (60% on average) and the flexural strength (43% on average) when compared to the plain mixture. On the other hand, a small dosage of FPFs (0.25%) generated less significant improvements in terms of flexural toughness, bulk density, and water erosion (on average, increment of 58% and reductions of 2% and of 38%, respectively, when compared to the unreinforced AM). Yet, the latter mixture presented reductions, on average, of compressive and flexural strengths of 24% and 16%, respectively, when compared to the plain mixture, and these reductions were significantly smaller than the reductions obtained by the largest FPF dosage, due to the significantly smaller number of fiber clusters presented by the 0.25% dosage when compared to the 1% dosage. Finally, the mechanical performance limitations exhibited by the incorporation of FPFs, especially in large dosages, are related to generated fiber clusters due to the inherent morphology of these FPFs as well as the traditional manual confection process of AMs. Therefore, this study recommends the implementation of FPFs in AMs, but in small dosages and/or suggests the implementation of a mechanical mixing/compaction process that guarantee a more uniform fiber distribution that reduces the generation of fiber clusters.
Durability of self-compacting concrete with addition of residue of masonry when exposed to carbonation and chlorides mediums
(2021) Silva Urrego, Yimmy Fernando; Delvasto, Silvio
This research studies the durability of self compacting concrete (SCC) with residue of masonry (RM) taken from construction and demolition waste (CDW) as partial replacement of Ordinary Portland Cement (OPC). For this purpose, three concrete mixes each with a different percentage of RM (0, 25% and 50% by volume). A control mixture with 100% OPC content was used as reference specimen to compare other two mixes. The fresh properties of SCC mixtures were performed using tests for slump flow, T50 cm slump flow, V-Funnel flow time, and L Box. The strength and durability properties were evaluated using a compressive strength test, water absorption, porosity, sorptivity, accelerated and natural carbonation test, and rapid chloride penetration test (RCPT). Further Scanning electron microscope (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TG-DTG) tests were also conducted for microstructure analysis. The results showed that the use of RM in SCC mixtures does not affect the properties in the fresh state. In the hardened state, the compressive strength of SCC with 25% RM showed an improvement of 3.6% and 9.1% after 180 and 720 days of curing respectively compared to reference mixture. However, the durability properties such as resistance to carbonation, the use of RM in SCC mixtures resulted in increased carbonation in both the accelerated and natural carbonation tests. On the other hand, the SCC with RM showed a better behavior to chloride penetration, locating in the low permeability zone at 180 and 360 days according to ASTM C1202.
Efecto de tratamientos en agregados reciclados sobre las propiedades en estado fresco y endurecido de concretos autocompactantes
(2022) Arcila Castro, Alejandro; Silva Urrego, Yimmy Fernando
La utilización de agregados reciclados provenientes de residuos de construcción y demolición (RCD) en nuevas obras civiles se considera el camino hacia la sostenibilidad. Esta investigación presenta la posibilidad del uso de agregado grueso reciclado (AGR) y agregado grueso tratado (AGT) de concreto en la elaboración de concretos autocompactantes (CAC). Para este propósito, dos métodos de tratamiento se realizaron a los AGR, uno de los tratamientos fue mediante desgaste mecánico en un molino de bolas y el otro fue mediante la inmersión en una solución acida (H2SO4) combinado con el desgaste mecánico. Para investigar el efecto de los AGR tratados sobre las propiedades mecánicas de los CACs, diferentes niveles de reemplazo (0%, 20% 40% y 100% en volumen) de agregado grueso natural (AGN) por AGR y AGT se realizaron. En estado fresco se evaluó capacidad de flujo, capacidad de paso y capacidad de llenado mediante el flujo de asentamiento con cono de Abrams, embudo en V y caja en L; y en estado endurecido se realizaron pruebas de resistencia a la compresión, tracción indirecta y flexión a los CACs. Los resultados muestran que los CAC con AGR presentaron una disminución en el desempeño de las propiedades en estado fresco y endurecido debido a la presencia del mortero adherido en este tipo de agregados, sin embargo, su trabajabilidad se encontró dentro de los parámetros establecidos por la EFNARC. Las propiedades mecánicas de los CAC con AGT presentaron un mejor desempeño en comparación a los CAC con AGR, debido al retiro del motero adherido mejorando la resistencia a la compresión todas las mezclas. Además, los CAC con AGT mostraron mejoras en las propiedades de permeabilidad presentando una reducción de porosidad de hasta un 6,06%.
Exploring the Potential of Alternative Materials in Concrete Mixtures: Effect of Copper Slag on Mechanical Properties and Carbonation Resistance
(2023) Silva Urrego, Yimmy Fernando; Villaquirán-Caicedo, Mónica A.; Izquierdo, Silvia
In this study, the effect on the flowability, compressive strength, absorption, sorptivity, and carbonation resistance of concrete with different copper slag (CS) replacement ratios was investigated. For this research, four concrete mixes with different percentages of CS were made (0%, 10%, 20%, and 30% of CS as replacement of cement by volume). In addition, the microstructure was analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TG–DTG). The results shows that the incorporation of CS reduces the workability and compressive strength of the mixtures, being more significant in concrete with 30% CS. The carbonation depth of concrete with CS increases monotonically with increasing CS. In addition, the compressive strength of the carbonated (20% and 30% CS) concretes show a loss of compressive strength at 90 days of exposure when compared to their water-cured counterparts. The use of low percentages of CS does not generate a decrease in workability and its mechanical effect is not significant at prolonged ages, so the use of this waste as SCM in percentages close to 10% is a viable alternative to the sustainability of concrete and the management of this residue.
Hydration kinetics and mechanical performance of cement pastes with copper slag as supplementary cementitious material
(2025) Burbano García, Claudia Patricia; Silva Urrego, Yimmy Fernando; Araya Letelier, Gerardo Andrés; González Hormazabal, Marcelo Andrés
The growing global demand for concrete infrastructure and cement highlights the need to mitigate the environmental impact of cement production. Incorporating alternative supplementary cementitious materials (SCMs) has emerged as a promising strategy. This research investigates the effect of copper slag (CS), a significant global mining-sector waste, as SCM in cement pastes, focusing on hydration and mechanical performance in both the short and long term. CS was used as SCM at dosages of 0 %, 10 %, 20 %, 30 %, and 50 % by volume. The hydration evolution of cement paste mixtures was evaluated using isothermal calorimetry, compressive strength tests, X-ray diffraction (XRD), differential thermogravimetry (DTG), and field emission scanning electron microscopy. Results indicate that up to 20 % CS replacement did not negatively affect compressive strength in the long term, while dosages above 20 % led to a monotonic reduction. XRD and DTG analyses validated the pozzolanic effect of CS, evidenced by the formation of new Fe-siliceous hydrogarnet phases and a reduction in CH content at later ages. Additionally, a predictive model combining random forest and polynomial regression techniques was developed to accurately forecast compressive strength as a function of CS dosage and curing time. This study concludes that incorporating up to 20 % CS as SCM can reduce CO2 emissions associated with the clinker factor without significantly compromising long-term mechanical performance, and offers a viable alternative for greener cement production.
Performance of Self-Compacting Concrete with Residue of Masonry and Recycled Aggregate under Sulfate Attack
(American Society of Civil Engineers, 2024) Silva Urrego, Yimmy Fernando; Delvasto, Silvio; Valencia, William; Araya Letelier, Gerardo Andrés
The use of byproducts as supplementary cementitious materials (SCMs) and recycled coarse aggregates (RCAs) can contribute tothe production of more sustainable self-compacting concrete (SCC) while modifying the durability properties of these mixtures. Thus, thisstudy addresses the combined use of concrete waste (CW) as RCA and residue of masonry (RM) as SCM, the CW and RM obtained fromconstruction and demolition waste, to generate SCC mixtures and to evaluate the performance of these mixtures under sulfate attack (5%Na2SO4and 5% MgSO4solutions). In detail, a reference SCC (M1) and three SCCs with 25% of RM and different level RCAs (0%, 50%, and100% replacement by volume) were cast. The hardened properties of the SCC mixtures were assessed in terms of compressive strength andsulfate attack. The results showed that the SCC mixtures with RM and RCA, cured in water, exhibited lower compressive strength results inall the evaluated ages compared with M1 (reference mixture, without RM and RCA). However, the SCC mixture with RM presented themaximum compression strength result among the different mixtures at 180 and 360 days. When mixtures were exposed to sulfate solutions,the SCC mixture with RM showed the best performance, and even the SCC mixtures with RM and RCA exhibited lower linear expansion andloss of compressive strength when compared with M1. The presence and severity of the sulfate attack were assessed via X-ray diffractionand scanning electron micrograph, which confirmed the presence of ettringite and gypsum in all the exposed SCC mixtures in the Na2SO4andMgSO4solutions.
Short and long-term physical and mechanical characterization of self-compacting concrete made with masonry and concrete residue
(2021) Silva Urrego, Yimmy Fernando; Delvasto, Silvio; Izquierdo, Silvia; Araya Letelier, Gerardo Andrés
This study aims to investigate the fresh and hardened properties of self-compacting concrete (SCC) made with residue of masonry (RM) and concrete waste (CW). The RM was added as supplementary cementitious material (SCM), replacing ordinary Portland cement (OPC), in 25% by volume and the SCC mixtures were designed incorporating five increasing amounts of CW as recycled coarse aggregate (RCA) (0%, 25%, 50%, 75%, and 100%), which were compared with a reference SCC with a 100% OPC and natural coarse aggregate (NCA). Both fresh state (workability, passing ability and viscosity) and hardened state (compressive strength, indirect tensile strength, flexural strength, porosity and capillary suction) properties of SCCs were evaluated, including short and long-term evaluations. The results show that RCA generates a loss in the fluidity, flow rate, passing ability and filling capacity of SCC, presenting the greatest decrease of workability in high percentages (75% and 100%) of RCA. However, all the SCCs managed to be in the required ranges by the EFNARC. In the hardened state, the mechanical properties generally weakened with increasing replacements of RCA, but the reduction rate was minimal when the content of RCA did not exceed 50%, being 1.22% less at 360 days when compared to the reference mixture’s compressive strength. Finally, the presence of RM at long ages generated a positive effect on properties when compared to the reference SCC, which can be used to compensate the moderate strength reductions generated by low-to-medium replacement ratios of RCA leading to sustainable SCCs incorporating both residues (RM and CW) with similar performance than conventional SCCs.
Short/long term assessment of precast concrete block waste as a supplementary cementitious material: mechanical performance, hydration, and microstructure evolution
(2025) Burbano García, Claudia Patricia; Lopez, M.; Araya Letelier, Gerardo Andrés; Silva Urrego, Yimmy Fernando; Zúñiga Rosales, Sebastián Alejandro; González Hormazabal, Marcelo Andrés
The massive production of cement and concrete is projected to grow significantly, with cement alone accounting for 7 %–8 % of global CO2 emissions. Reducing the environmental impact of the cement industry is critical, and low-carbon cement blends incorporating supplementary cementitious materials (SCMs) valorized from industrial wastes are a promising near-term solution. Precast concrete block waste (PCBW), an industrial waste from precast concrete plants and masonry demolition, offers potential as an SCM. This study evaluates the effects of PCBW replacement (0 %, 10 %, 20 %, and 50 % by volume) in cement paste mixtures (CPMs) on hydration and mechanical performance over short (3 days) and long (90 days) terms. The evaluation included isothermal calorimetry, compressive strength, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential thermogravimetric (DTG) analysis, and field-emission scanning electron microscopy. Predictive models using polynomial regression and support vector regression (SVR) were developed to estimate CPM compressive strength based on PCBW replacement levels and curing ages. Results showed that a 10 % PCBW replacement did not statistically affect CPM compressive strength, while 20 % replacement reduced it by 12 % at 90 days. XRD and FTIR analyses revealed high quartz and calcite content in PCBW, consistent with its chemical composition. DTG confirmed the low pozzolanic activity of PCBW compared to other SCMs. The predictive models demonstrated accuracy through 5-fold cross-validation. Using PCBW as an SCM up to 10 % is recommended to reduce environmental impacts without compromising mechanical performance.
Sulfate attack performance of concrete mixtures with use of copper slag as supplementary cementitious material
(Springer Science and Business Media B.V., 2025) Silva Urrego, Yimmy Fernando; Burbano-Garcia, C.; Araya-Letelier, G.; Izquierdo, S.
© 2025 The AuthorsOne of the most significant causes of concrete structural degradation is sulfate attack, stemming from the interaction between hydration products of cement and sulfate ions, which causes physical and microstructural changes in the material matrix that can severely affect concrete's mechanical performance. This study evaluates the short and long term (up to 360 days) sulfate resistance performance of concretes incorporating copper slag (CS), a major global mining waste, as supplementary cementitious material (SCM). Three concrete mixtures with increasing CS replacement levels (i.e., 0 %, 20 % and 50 % by volume replacement of ordinary Portland cement) were exposed to aggressive sulfate environment, specifically sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) solutions, each containing 33,800 ppm of SO4–2. A comprehensive analysis of physical (linear expansion and visual inspection), mechanical (compressive strength and modulus of elasticity) and mineralogical (scanning electron microscopy (SEM) and X-ray diffraction (XRD)) properties was conducted. The results indicated that physical changes were most significant in the mixtures exposed to MgSO4 compared to those exposed to Na2SO4. Additionally, higher compressive strength losses at 360 days were observed, with reductions of 18 %, 21 % and 15 % for the mixtures with 0 %, 20 % and 50 % of CS as SCM, respectively. The elastic modulus results showed a similar trend to compressive strength, with the 20 % CS mixture exhibiting comparable stiffness to the reference, while the 50 % CS mixture showed a noticeable reduction. In mineralogical terms, characteristic crystals such as ettringite and gypsum were identified in all exposed concretes by XRD and SEM. Finally, these findings demonstrate that incorporating CS as an SCM does not adversely affect the sulfate resistance of concrete mixtures and supports its potential use in durable, sustainable concrete applications.
Use of Abandoned Copper Tailings as a Precursor to the Synthesis of Fly-Ash-Based Alkali Activated Materials
(2025) Reyes-Román, Arturo; Samarina, Tatiana; Castillo-Godoy, Daniza; Takaluoma, Esther; Campo, Giuseppe; Araya Letelier, Gerardo Andrés; Silva Urrego, Yimmy Fernando
This study evaluated the feasibility of reusing abandoned copper mine tailings (Cu tailings) as a precursor in the production of fly-ash-based alkali-activated materials (FA-AAMs). Two formulations were developed by combining FA and Cu tailings with a mixture of sodium silicate and sodium hydroxide as alkaline activators at room temperature (20 °C). Formulation G1 consisted of 70% Cu tailings and 30% fly ash (FA), whereas G2 included the same composition with an additional 15% ordinary Portland cement (OPC). The materials were characterized using X-ray fluorescence (XRF), -X-ray diffraction (XRD), field emission scanning electron microscopy with energy-dispersive spectroscopy (FESEM-EDS), and particle size analysis. While FA exhibited a high amorphous content (64.4%), Cu tailings were largely crystalline and acted as inert fillers. After 120 days of curing, average compressive strength reached 24 MPa for G1 and 41 MPa for G2, with the latter showing improved performance due to synergistic effects of geopolymerization and OPC hydration. Porosity measurements revealed a denser microstructure in G2 (35%) compared to G1 (52%). Leaching tests confirmed the immobilization of hazardous elements, with arsenic concentrations decreasing over time and remaining below regulatory limits. Despite extended setting times (24 h for G1 and 18 h for G2) and the appearance of surface efflorescence, both systems demonstrated good chemical stability and long-term performance. The results support the use of Cu tailings in FA-AAMs as a sustainable strategy for waste valorization, enabling their application in non-structural and moderate-load-bearing construction components or waste encapsulation units. This approach contributes to circular economy goals while reducing the environmental footprint associated with traditional cementitious systems.
Valorization of Medical Waste in Cement-Based Construction Materials: A Systematic Review
(2025) Murillo, M.; Manzano, S.; Silva Urrego, Yimmy Fernando; Burbano García, Claudia Patricia; Araya Letelier, Gerardo Andrés
Worldwide, the healthcare industry produces massive quantities of medical waste (MW), most of which is incinerated, releasing large quantities of dioxins, mercury, and other pollutants. Despite this, only a limited number of studies have explored the incorporation of MW into construction materials, with a special focus on cement-based construction materials (CB-CMs). However, to the best of the authors’ knowledge, no existing review formally structures, summarizes, correlates, and discusses the findings of previous studies on MW in CB-CMs to encourage further research and applications of this promising alternative. Therefore, the added value of this study lies in providing an innovative and critical analysis of existing research on the use of MW in CB-CMs, consolidating and evaluating dispersed findings through a systematic literature review, enhancing understanding of the topic, and identifying knowledge gaps to guide future research. A robust systematic literature review was conducted, encompassing 40 peer-reviewed research articles, retrieved from the Web of Science Core Collection database. The methodology involved a three-stage process: a descriptive analysis of the included articles, the identification and synthesis of key thematic areas, and a critical evaluation of the data to ensure a rigorous and systematic report. The selection criteria prioritized peer-reviewed research articles in English with full text availability published in the last 7 years, explicitly excluding conference papers, book chapters, short reports, and articles not meeting the language or accessibility requirements. The results indicate that the influence of MW in CB-CM varies significantly. For example, while the incorporation of face masks as fiber reinforcement in concrete generally enhances its mechanical and durability properties, the use of gloves is less effective and not always recommended. Finally, it was found that further research is needed in this field due to its novelty.
Valorization of Recycled Aggregate and Copper Slag for Sustainable Concrete Mixtures: Mechanical, Physical, and Environmental Performance
(2024) Caballero Arredondo, Pamela Wendy; Silva Urrego, Yimmy Fernando; Araya Letelier, Gerardo Andrés; Hernández López, Héctor Enrique
The increasing environmental impacts caused by the high demand for concrete production have underscored the need for sustainable alternatives in the design of eco-concrete mixtures. Additionally, important industries, such as construction and mining, generate massive amounts of waste/by-products that could be repurposed towards sustainability. Consequently, this study investigates the valorization of copper slag (CS), a by-product of the mining industry as a supplementary cementitious material (SCM), and concrete as recycled coarse aggregate (RCA), derived from construction and demolition waste, as partial substitutes for Ordinary Portland Cement (OPC) and natural coarse aggregate (NCA), respectively. Eco-concrete mixtures were designed with varying replacement levels: 15% for CS, and 0%, 20%, 50%, and 100% for RCA. The mechanical properties (compressive, indirect tensile, and flexural strengths), permeability characteristics (porosity and capillary suction), and environmental impacts (carbon footprint) of these mixtures were evaluated. The results showed that the use of CS and of increasing proportions of RCA led to a monotonic loss in each of the concretes' mechanical strength properties at 7, 28 and 90 days of curing. However, at extended ages (180 days of curing), the concrete mixtures with CS and only NCA presented an average compressive strength 1.2% higher than that of the reference concrete (mixture with only OPC and natural aggregate). Additionally, the concrete mixture with CS and 20% RCA achieved 3.2% and 5.8% higher average values than the reference concrete in terms of its indirect tensile strength and flexural strength, respectively. Finally, a cradle-to-gate life cycle assessment (LCA) analysis was implemented, whose results showed that the greatest effect on reducing the carbon emission impacts occurred due to the substitution of OPC with CS, which confirmed that the adequate technical performances of some of the concrete mixtures developed in this study are positively complemented with reduced environmental impacts. Moreover, this study presents a viable approach to minimizing resource consumption and waste generation, contributing to the advancement of eco-friendly construction materials, which aligns with the sustainable development goals.

Browsing by Author "Silva Urrego, Yimmy Fernando"

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