Uso de relaves mineros como agregado fino en concreto de baja resistencia para veredas en una mina peruana (2025)

With the global demand for concrete on the rise, the need to conserve natural resources has become critical, driving the shift towards more sustainable construction practices. This study explores the potential of three distinct approaches to enhance concrete performance while reducing environmental impact and ensuring sustainable development. The research aims to develop sustainable concrete solutions by utilising recycled materials and waste products. The study consists of three groups; Group 1: replacing natural aggregates with recycled coarse aggregates (RCA) and recycled fine aggregates (RFA) at various ratios (30%, 50%, 70%, and 100%), Group 2: partially replacing cement with fly ash (FLA) at 20%, 50%, and 70% with RCA consistently at 30%, and Group 3: incorporating recycled polypropylene fibres (RPF) at 2%, 4%, 6%, and 8% to replace coarse aggregates. To optimise concrete mix behaviour, this study employs the Two-Stage Mixing Approach (TSMA) for Group 1 and the Design of Experiments (DOE) methodology for Groups 2 and 3. The study reveals that fresh concrete mixtures incorporating higher proportions of RCA (Group 1), RFA (Group 1), and FLA (Group 2) exhibited reduced workability, with slump values decreasing by 10.23% to 22% compared to the control mix made with natural aggregates. Conversely, increasing the content of recycled polypropylene fibres (RPF) led to a notable enhancement in workability, with slump readings increasing twofold compared to the control mix. The regular distribution of higher percentages of RPF increased the fibre-cement paste’s surface area, promoting better bonding and consequently enhancing the workability of the fresh concrete. Moreover, in Group 1, concrete blends with 30% RCA exhibited the highest compressive strength, surpassing the control mix by 11.43%. Meanwhile, blends with 30–50% RFA showed significant gains, with compressive strength increases ranging from 3.9% to 16.88%. Likewise, flexural strength reached its peak, increasing by 10% with 30% RCA and by 11.11% to 19.44% with 30% to 50% RFA, compared to the control mix. In Group 2, the optimal combination of 30% RCA and 20% FLA yielded significant strength gains, with compressive strength increasing by up to 24.56% and splitting tensile strength by up to 32.79%. In Group 3, incorporating RPF particles at a dosage of 2% to 4% yielded satisfactory compressive and flexural strength results, comparable to those of control specimens. The failure modes under various loads were analysed for each group, and correlations between compressive, splitting, and flexural strengths were established. This study highlights the potential of eco-friendly concrete incorporating recycled aggregates and waste materials as a sustainable construction solution, contributing to waste reduction, resource conservation, and environmentally responsible practices.

The increasing costs of construction materials and the rapid depletion of natural aggregates have highlighted the urgent need for sustainable alternatives in the construction industry. In this context, plastic waste, particularly high-density polyethylene (HDPE), has become a significant environmental challenge due to the global surge in plastic production and disposal. This study investigates the feasibility of using synthetic coarse aggregates derived from post- consumer HDPE plastic waste, combined with various filler materials, as an environmentally friendly substitute for natural aggregates in concrete. The research focuses on developing two types of synthetic aggregates, one consisting of HDPE mixed with fly ash and bottom ash and the other comprising HDPE combined with ceramic waste powder. The synthetic aggregates were created by varying the proportions of HDPE and filler materials, followed by extensive testing of the resulting plastic aggregate cubes for compressive strength and shrinkage. The results revealed that the optimal mix for the first type of aggregate consisted of 60% HDPE, 15% fly ash, and 25% bottom ash, while the second type achieved the best performance with a blend of 80% HDPE and 20% ceramic waste. These compositions demonstrated the highest compressive strength, making them the most effective synthetic aggregate blends for potential use in construction. Subsequent to developing these optimal mixes, concrete cubes of different grades (15, 20, 25, and 30) were cast using both natural aggregates and a full (100%) replacement with the developed plastic aggregates. The findings of the study indicate that concrete made with synthetic plastic aggregates exhibited lower compressive strength and density compared to traditional concrete. However, these materials also resulted in significantly reduced production costs. Notably, replacing conventional natural aggregates with synthetic aggregates in higher- grade concrete mixes led to substantial cost savings, with reductions in production expenses ranging from 20% to 24% per footing in a sample building. The research underscores the potential of incorporating synthetic coarse aggregates made from HDPE plastic waste, along with fly ash, bottom ash, and ceramic waste, as a sustainable and economically viable alternative to natural aggregates in concrete construction. The use of such synthetic aggregates not only addresses environmental concerns related to plastic waste but also offers a cost-effective solution that does not compromise the structural integrity of the concrete. These findings contribute to the growing body of knowledge on sustainable construction practices, presenting a promising pathway for the industry to reduce its environmental footprint while maintaining economic efficiency.

With the continuous rise in construction and demolition waste (CDW) generation and the increasing demand for sustainable construction materials, this study aims to explore the potential of utilizing recycled concrete aggregate (RCA)—the most abundant component of CDW—as a replacement for natural aggregate (NA). Mortar samples incorporating untreated recycled fine aggregate (RFA), natural fine aggregate (NFA), and carbonated RFA (CRFA) were produced to determine whether the mechanical and durability drawbacks of RFA can be mitigated through accelerated carbonation. In this context, the workability, mechanical strength, water absorption capacity, capillary water absorption behavior, freeze–thaw and chloride permeability properties of the mortars were analyzed. The results indicate that the negative impact of RFA on engineering properties can be significantly reduced through accelerated carbonation. Despite all aggregates being in a saturated surface dry state, RFA exhibited the lowest flowability, while NFA had the highest. In strength tests, CRFA-containing mortars achieved performance levels comparable to those with NA. However, RFA mixtures demonstrated considerably higher water absorption and permeability than NA, while CRFA improved these properties. Additionally, RFA mortars experienced greater weight loss during freeze–thaw cycles, but carbonation treatment helped mitigate this deterioration. These findings highlight the potential of accelerated carbonation treatment as an effective method for upgrading RCAs, contributing to more sustainable construction practices.

The existing contractor selection models, and specifically the lowest bidder model, do not encourage contractors to adopt sustainable construction practices. This article proposes a new bidding model that incorporates sustainable construction practices. The proposed A + S model takes into consideration the bid price (A) and the monetary value for the use of sustainable construction practices (S). The (S) parameter is taken as a negative value to act as an incentive rather than a deterrent. Twenty sustainable construction practices were identified. A survey was conducted to measure the importance of each practice. The Analytic Hierarchy Process (AHP) was used to calculate the weight of each practice. The top five sustainable practices were eliminate toxics, air & dust control, project management, health & safety and quality management. The average monetary value of the selected sustainable construction practices, relative to construction cost, was 20%. The proposed model encourages contractors to implement sustainable construction practices to improve their chances in winning bids.

This study evaluates the potential of hemp hurds, an agricultural by-product, as a partial replacement for fine aggregates in concrete. Hemp hurds at replacement levels of 5%, 10%, and 15% by volume, and its effects on the mechanical and durability properties of concrete through both experimental and analytical approaches. Laboratory tests assessed compressive strength, tensile strength, workability, and durability, while finite element analysis using ANSYS simulated the mechanical performance under various loading conditions. Results indicated that incorporating hemp hurds improved workability due to its water absorption and retention characteristics. Compressive strength showed a moderate reduction, with more significant losses at higher replacement levels, while tensile strength was minimally affected at lower percentages. Durability testing revealed that hemp hurds enhances moisture retention, contributing positively to the mix's performance under environmental stresses. Analytical results from ANSYS simulations aligned closely with experimental data, validating the observed trends. Additionally, the use of hemp hurds promotes sustainability by reducing reliance on natural aggregates and utilizing agricultural waste. This study concludes that hemp hurds is a viable, eco-friendly alternative in concrete, particularly at lower replacement levels, offering a promising pathway toward sustainable construction practices.

This study presents a systematic experimental investigation on the feasibility of using recycled fine aggregate (RFA) as a partial to full replacement of natural fine aggregate in structural concrete. Concrete mixtures were prepared with RFA replacement levels ranging from 0% to 100%, and their fresh, mechanical, and durability properties were evaluated. Compressive strength decreased by approximately 17.3% at 100% RFA replacement (from 38.19 MPa to 31.58 MPa), while split tensile strength showed a higher reduction of about 20.3% (from 3.16 MPa to 2.52 MPa). Compressive strength showed the least sensitivity to RFA incorporation, followed by flexural strength, while split tensile strength exhibited the highest sensitivity due to its dependence on interfacial transition zone quality. Statistical analysis confirmed strong linear correlations and significant relationships between RFA content and strength reduction. Durability performance assessed through water absorption increased by approximately 51% and sorptivity by about 38% at 40% RFA, while sharper increases were observed only at higher replacement levels (≥60%). Compressive, split tensile and flexural strength reduction below 7%, 12%, and 8% respectively, which remain within acceptable limits for structural-grade concrete. The combined results suggest that RFA can be effectively utilized as a sustainable alternative to natural sand at moderate replacement levels. The findings contribute to performance-based guidelines for RFA utilization and support its application in sustainable and circular concrete construction practices.

This paper investigates durability related properties of concretes containing copper heap leach residue (CHLR) as partial replacement of natural fine and coarse aggregates. The use of CHLR as aggregates in concretes promotes the reduction of the dependance on natural aggregates, upcycling of the waste as aggregates and the reduction of carbon footprint associated with natural aggregate productions. In this study, CHLR was washed, dried, and sieved to separate fine aggregate and coarse aggregate, and concretes were prepared with a cement content of 400 kg/m3 and water-cement ratio of 0.435 by replacing 25-75% natural fine and coarse aggregates. The concrete containing 50% CHLR as a partial replacement of natural CA and FA gained compressive strength of 52.9 and 54.0 MPa; drying shrinkage of 662 and 538 με; volume of permeable voids of 6.2 and 5.7%; 1485 and 2640 coulomb of charge passed in chloride permeability; and primary sorptivity coefficients of 4.0 × 10−3 and 4.3 × 10−3 mm/sec0.5 at 180 days, respectively. In contrast, these properties for the control specimens at the same age were 59.1 MPa, 394 με, 5.19%, 1280 coulomb, and 2.5 × 10−3 mm/sec0.5, respectively. The compressive strength and durability aspects declined in concretes using 75% CHLR coarse and fine aggregates. Existing analytical models for durability related properties of concrete containing natural aggregates are compared to that of the concretes using CHLR. Finally, backscattered electron images coupled with energy dispersive x-ray spectroscopy of the CHLR concretes were analyzed to understand the pore refinement, interfacial transition zones, microcracks, and hydration products influencing the durability aspects.

In addressing the dual challenges of sustainable waste management and environmental conservation in the construction industry, particularly the disposal of waste tire crumb rubber (CR) and the demand for eco-friendly building materials, this study explores a novel solution. It examines the sustainable incorporation of waste tire crumb rubber and mineral additions—namely silica fume (SF), marble slurry powder (MSP), and fly ash (FA)—as partial substitutes for natural fine aggregates and cement in concrete. Through comprehensive testing of seventeen concrete samples, the study reveals that the specific mix of R10S5M10F15 that contained 10% crumb rubber as replacement of fine aggregates, and 5% silica fume, 10% marble slurry powder and 15% fly ash as replacements of cement, not only achieves compressive and split tensile strength comparable to the control mix, while the 90 days flexural strength was improved by 4.48%; credited to SF’s pozzolanic action and the filler effects of MSP and FA, but also that the inclusion of CR, while reducing compressive strength due to material variations, enhances ductility and improves resistance to sulfate and acid attacks, despite increasing water absorption. The primary goal of this research is to investigate the feasibility and effectiveness of using waste materials in concrete to foster more sustainable construction practices. The objectives include a detailed assessment of the mechanical properties and durability of concrete incorporating these waste materials, aiming to determine the optimal mix proportions for their effective utilization. This study’s novelty lies in its detailed analysis of the synergistic effects of combining CR, SF, MSP, and FA in concrete, contributing to the field by offering a sustainable alternative approach to traditional concrete formulations and highlighting the delicate balance required for optimized concrete performance.

The construction industry is increasingly prioritizing sustainable and eco-friendly practices, resulting in a growing interest in utilizing waste materials in concrete production. As environmental concerns continue to grow, innovative solutions are becoming essential to reduce waste and promote sustainability. One promising approach involves incorporating waste materials into concrete as internal curing agents (ICAs) to address the challenges associated with proper concrete curing. Proper curing is essential for enhancing the durability and mechanical properties of concrete, but conventional curing methods often have limitations, especially in concrete with a low water/cement ratio. This has led to a significant focus on exploring alternative methods, with internal curing gaining considerable attention. The concept of internal curing involves utilizing materials based on the ability to absorb and release water within the concrete matrix. This facilitates a more consistent and extended curing process. This research intends to address a gap in sustainable construction practices by assessing the feasibility of using roof tile waste as an internal curing aggregate (ICA) to replace fine aggregates in roller-compacted concrete (RCC). The utilization of roof tile waste not only encourages recycling and reduces landfill waste but also leverages its water absorption and desorption properties to improve the curing process. The research involved a comprehensive series of laboratory experiments to assess the potential usage of roof tile waste as an ICA. Furthermore, the study evaluates the impact of roof tile waste on the mechanical properties of RCC, specifically focusing on compressive strength, tensile strength, and flexural strength. To achieve this, RCC samples were cast with varying percentages of roof tile aggregates (RTA) replacing fine aggregates: 5%, 10%, and 15%. Each sample was subjected to testing to assess its performance compared to externally cured conventional RCC and uncured conventional RCC. The findings from the experiments revealed that the incorporating of roof tile waste as an ICA significantly affects the mechanical properties of RCC. The optimal performance for internal curing with RTA occurs at a 10% replacement level, balancing the benefits of internal moisture retention and the mechanical integrity of the concrete. The research emphasizes that utilizing 10% RTA replacement can lead to significantly improved early-age properties, demonstrating an 18% increase in 3-day compressive strength compared to traditionally cured RCC. This advancement is advantageous for pavement construction as it facilitates quicker access to traffic and shortens construction schedules. However, the study also identified certain constraints. Even though the early compressive strength displayed substantial enhancement, the tensile and flexural strengths of RCC samples with RTA were lower than those of conventionally cured RCC. This indicates that while roof tile waste is effective in enhancing early age compressive strength, further optimization is needed to improve its impact on tensile and flexural properties.

In this study, effects of high blazing temperature with varied time durations on mechanical behavior of normal concrete containing recycled tire rubber as a fine aggregate (RTRFA) have been presented. RTRFA is used as a partial replacement of natural fine aggregate to make rubberized concrete. Generally, concrete used in structural members must satisfy fire resistance requirements in building codes. Therefore, this paper aims at studying the performance of the rubberized concrete prior and after its exposure to fire in accordance with ISO 834 curve for firing. It has been stipulated that the presence of tire rubber particles is mostly for the consideration of environment safeguard. In this investigation, five different concrete mixes were prepared with Ordinary Portland Cement, natural fine and coarse aggregate, with fine aggregate replacement ratios (0%, 6%, 12%, 18% and 24%) by weight. From these mixes, 60 cylindrical specimens (100mm diameter × 200mm high) and 60 cubic specimens (150mm×150mm×150mm) were prepared. These concrete specimens were divided into four groups, consisting of 15 cubes and 15 cylinders each. The first group (so called “control”) were tested without exposing it to fire and the remaining three groups were separately subjected to fire for three different time periods vis. (20, 40 and 60 minutes) in a furnace fabricated according to ASTM E119. Then the concrete specimens were tested to observe the post-fire mechanical properties including split tensile strength, compressive strength and ultrasonic pulse velocity. The results of time-temperature curves, slump, fresh density, hardened density, percent-mass loss, compressive strength, split tensile strength of all the mixes are presented. The results showed that both the compressive strength and split tensile strength of concrete mixes decreased with higher percentage replacement of fine aggregate by RTRFA before and after exposure to fire. Moreover, longer time of fire duration or higher replacement ratios leads to further strength reduction of compressive and split tensile strengths. Additionally, it was found that the usage of ultrasonic pulse velocity for concrete samples containing more than 6% of RTRFA as a replacement of sand gives unreasonable measurements. Finally, statistical equations were derived to predict these properties of concrete with RTRFA replacements.

Objective: This article aims to analyze and revalidate the available scientific evidence on the impact of sustainable practices in construction and its environmental impacts. Theoretical framework: Civil construction plays a crucial role in economic and social development, however, its activities cause significant environmental impacts. Construction activities use large amounts of natural resources, such as water, wood, sand and minerals. Method: The present study is based on an exploratory and analytical perspective, with the aim of investigating in detail the connection between environmental sustainability and the impacts of civil construction. Databases such as: Scielo, Scopus and Web of Science were used, using specific keywords related to sustainability and civil construction. Results and conclusion: The studies reveal that the incorporation of sustainable practices in civil construction is an urgent and viable need. The effectiveness of these practices has shown positive results in reducing impacts, demonstrating that it is possible to align development with environmental responsibility. Research Implications: The results of this investigation offer valuable insights for designing sustainable government policies. The findings highlight the relevance of prioritizing and reinforcing sustainable practices in construction. Originality/value: The study incorporates a diverse range of relevant theories, ranging from environmental theories to construction models focused on consumerist practices. This comprehensive methodology offers a broader and more detailed view of the intersection between sustainability and civil engineering.

PurposeSustainable construction practice is structured on regulatory and non-regulatory policies in developed and most developing countries. With the gradual uptake of sustainability concerns in the construction industry, this paper aims to identify the strategic need for clear-cut policies to improve sustainable construction practice. Previous studies have harped on the need for regulatory and industrial/organisational policies on improving sustainable construction practice within the Nigerian construction industry.Design/methodology/approachA questionnaire survey was used to evaluate the perspectives of construction professionals on the policy barriers for sustainable construction practice in Nigeria, and 46 policy barriers were identified. A total of 249 questionnaires were returned and useable for analysis.FindingsFactor analysis revealed four clusters in the policy barriers to sustainable construction practice in the following order of significance: implementation strategies for sustainable construction practice, owners/client inputs for sustainable construction practice, stakeholder’s policy barriers and governmental and regulatory policy barriers.Practical implicationsMitigating the identified barriers through effective policies will require adequate inputs from all relevant policymaking stakeholders and ensure improved sustainable construction practice among stakeholders and policymakers in the industry. This will in turn set a high standard and promote the practice of sustainable construction.Originality/valueThis study goes a step further in identifying the policy issues needed to ensure a smooth implementation of sustainable construction practice. The research findings will serve as a guide for policymakers in developing countries that through mitigation of the identified barriers, sustainable construction practice will be promoted.

The report presents a comparative examination of the experimental results of the characteristics of fresh and cured concrete with various natural with recycled coarse and fine aggregate replacement ratios. Crushing leftover concrete from laboratory test cubes and precast concrete columns yielded recycled coarse aggregate. Stone dust was used in place of recycled fine aggregate. One of the most significant components of a reinforced structural part is concrete. Concrete has an inextricable influence on reinforced concrete constructions. Concrete that isn't strong enough puts the entire structure in harm. Many structures nowadays fail as a result of a lack of strength. The mechanical properties of concrete changed by stone dust as a fine aggregate replacement material are investigated in this work. A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse and fine aggregate are presented in the paper. Recycled coarse aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Recycled fine aggregate was replaced by stone dust. Concrete is one of the most important components in reinforced structural member. In reinforced concrete structures concrete have some inseparable influence. Lacking in concrete strength endanger the whole structure. Now a day it is seen that many structures fails due to lack of strength. In this paper investigate experiment is reported on the mechanical properties of concrete modified by stone dust as replacing material of fine aggregate and demolished concrete waste as replacing material of coarse aggregate and a study is conductto determine the engineering properties of compressive strength, tensile strength, flexural strength and water absorption capacity of partially replacement of natural sand and natural aggregate. In recent days the demand of river sand is increasing due to its lesser availability. Hence the practice of partially replacing river sand with stone dust is taking a tremendous growth. Due to critical stage of natural aggregate the availability of demolished concrete as recycled aggregate. Using discarded concrete as recycled aggregate conserves natural aggregate, lowers landfill impact, reduces energy use, and potentially saves money. The materials of the future are recycled aggregate. Stone dust and destroyed concrete waste were used to replace 25 percent, 50 percent, 75 percent, and 100 percent of fine and coarse aggregate, respectively. After a 28-day curing period, concrete samples (cubes, cylinders, and beams) are cast and evaluated. To produce the effect on mortar, several members were built utilising the above percentage. Modified concrete is compared to regular concrete in terms of strength. The strength parameters of concrete employing stone dust as fine aggregate and demolished concrete debris as coarse aggregate are observed to increase in compressive strength, flexural strength, and tensile strength. It was discovered that the concrete may be used as structural members in buildings and other structures.

In this study, locally produced recycled fine aggregate from concrete demolition waste was investigated for potential replacement of sand in new concrete mixes. Tests for the waste material included visual examination, chemical composition, grain size distribution, specific gravity, and fineness modulus. Tests on the incorporated recycled fine aggregate in new concrete mixes involved tests of the hardened plain concrete product. In total, eight concrete mixes were considered, of which four had low cement content with 30 MPa target strength, and the other four had high cement content with 55 MPa target strength. For each cement content, the four concrete mixes incorporated fine aggregate replacement ratios of 0% (control), 25%, 50%, and 100%. The hardened concrete tests involved cubes, cylinders, and prisms. The tests addressed compressive strength, tensile strength, and modulus of rupture in accordance with the relevant ASTM standards. In all cases, the average of two tested samples at the age of 28 days was considered. Results of the study showed that the recycled fine aggregate has some cementitious properties, which is capable of hardening when mixed with water and left to dry, even without adding cement from exterior sources. All tested concrete specimens made with recycled fine aggregate exhibited compressive and tensile strengths at least equal to 75% that of the control specimens that contained natural fine aggregate. However, for concrete mixes utilizing low cement content that can yield a compressive strength around 30 MPa with natural aggregate, replacement of 25% or 100% of the natural fine aggregate by weight with locally produced recycled fine aggregate from crushed old concrete can match and often exceeds the compressive and tensile strength of concrete made with virgin aggregate.

Evaluation of strength characteristics and identifying the optimum dosage with the impact of partial replacement of recycled fine and coarse aggregate from construction and demolition waste