Revista de la Construcción. Journal of Construction

Sensor-based activity recognition for construction activities on site using stacking ensemble method

İbrahim Karataş — 2025-09-03

Automatically recognizing workers' activities can improve productivity, safety, and management in construction. This study aimed to collect data using sensors from workers in a real construction site environment to compare various machine learning models for recognizing workers' activities. Additionally, it sought to develop a novel meta-ensemble machine-learning model to enhance prediction accuracy. For this purpose, formwork, rebar, concrete, walling, roughcast, gypsum, painting, and tiling activities were analyzed. The XGB model had the highest prediction accuracy at 96.14%. This study created a stacking meta-ensemble model to increase these prediction accuracy rates further. As a result of trying various variations, the Stacking model, which was formed by combining the SVM, RF, GBM, and XGB models and choosing the XGB model as the meta-learner, reached 98.53% prediction success. The results demonstrate that ensemble machine-learning models surpass basic machine-learning models' ability to predict outcomes accurately. By using this proposed stacking ensemble model, it is expected to create an automatic system that will calculate the productivity, risks, and fatigue of workers in future studies.

Impact of supplementary cementitious materials (SCMs) on physical-mechanical properties and microstructure of styrene polyacrylic (SPA) polymer modified mortars

Hichem Berkak — 2025-09-03

Polymer-modified mortars (PMMs) have attracted increasing attention for their promising properties, multiple applications, and relatively affordable cost compared to other polymer mortars. This study investigates the impact of substituting 30% of ordinary Portland cement (OPC) with SCMs on the physical-mechanical and microstructural properties of PMM based on a new type of latex polymer, styrene polyacrylic (SPA). This is to contribute to the development of more effective and sustainable PMM, while reducing the carbon footprint associated with cement use. For this purpose, an OPC mortar and a total of 7 mortar mixtures were designed, all with a polymer-to-binder (P/B) ratio (in powder) of 7.5%. The control PMM mixture contains only OPC and SPA latex as binders while the remaining mixtures include binary and ternary cement mixtures, composed of OPC, silica fume (SF), natural pozzolan (NP) and limestone fillers (LF). Tests of workability of fresh mortars and dry weight were carried out and flexural tensile and compressive strengths of hardened mortars were measured over a curing period ranging from 3 to 365 days. The microstructure of PMMs was also studied using XRD analysis and SEM images. The results demonstrated the efficacy of LF integration in improving the workability of PMM while NP or SF addition has a detrimental effect on the rheological properties of PMM, as the flow time increased by 24% and 37%, respectively, so it is necessary to increase the superplasticizer content. The incorporation of SCMs also resulted in the production of lightweight PMMs as evidenced by the reduced density of SCMs. For PMMs with binary binders, the replacement of OPC with 30% SF leads to a significant increase in compressive strength after 28 days ranging from 7 to 15%, along with an improvement in the PMM microstructure. Finally, it should be noted that the combination of NP and SF represents the optimal formulation for the PMM ternary mixture. After 28 days, this combination noticeably increases compressive strength by 8–10% without any decrease in tensile strength.

Experimental investigation on fresh and mechanical properties of self-compacting concrete using sisal and abaca fibers

Selesca Devi S. — 2025-09-03

The influence of natural fibers on self-compacting concrete (SCC) with a constant 15% silica fume (SF) was investigated. The natural fibers, namely Abaca fiber (AF) and sisal fiber (SiF), were used in SCC. Initially, it aims to determine the ideal dosage of fibers under mono addition by investigating their fresh properties and mechanical properties. In SCC, the addition of AF 0.25% and 0.5%, and SiF from 0.25% to 1.5% were used with a 0.25% increment. AF at 0.25% ensured a good flow with 6.6% higher compressive strength and 4.16% higher split tensile strength than 0.5% AF. SiF up to 1% obtained good tensile and compressive strength over the optimal AF of 0.25%. Further, combining optimal mono fibers to examine the behavior of hybrid fiber additions in SCC. Hybrid fiber incorporation abruptly reduced the spread flow diameter (SFD), ranging from 330-375 mm, whereas in the mono fiber addition, SFD was 360-600 mm. However, the hybrid fiber combination with AF (0.25%) and SiF (0.5%) performed better than other hybrid mixes, mono fiber additions, and control mixes in terms of compressive strength (22.22%), split tensile strength (26.08%), flexural strength (28%), and impact energy (527.95 %). From microstructure studies through SEM examination, the presence of SF refined the pores caused by the addition of fibers and then enhanced the bond between the fiber and the concrete matrix.

Behavior of moment-resistant frames after shear-axial failure of reinforced concrete column

Erkan Bicici — 2025-09-03

Failure or collapse of the entire structure triggered by a local element-level failure can be defined as progressive collapse. The degradation and loss of the capacity of an element leads to a new load path on the structure, which creates a new load-carrying mechanism. The most common approach is the sudden removal of the column and pushdown analysis. In this study, a new method is proposed to simulate progressive collapse of reinforced concrete structures. The proposed method includes the shear-axial interaction of reinforced concrete columns and consideration of axial shortening of columns due to lateral strength degradation. The proposed method may be applicable for the progressive collapse analysis of a concrete structure under an earthquake. The proposed method is tested in 2D and 3D typical benchmark reinforced concrete frames. The behavior of the frames calculated by the proposed method is compared with the results obtained from pushdown analysis to validate the accuracy of the model. A good agreement is observed between the proposed method and pushdown analysis. The shear-axial interaction method sufficiently covers the behavior of frame analysis with the sudden loss of a column. Thus, the proposed method simulates more realistic failure under cyclic loading, such as earthquakes.

Performance evaluation of mercerized raffia and sisal fibers in engineered cementitious composites

Mukesh Thottipalayam Shakthivel — 2025-09-03

This study investigated the use of raffia and sisal fibers as replacements for coarse aggregates in engineered cementitious composite (ECC) to improve its flexural properties. The fibers were treated with mercerization, a common chemical process, to alter their structure and surface morphology. The fiber characteristics were analyzed using various techniques, including Field Emission Scanning Electron Microscope (FESEM), Fourier Transformation Infrared (FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimeter (DSC), and tensile test. The mechanical properties (compression, elastic modulus, direct tensile, and flexural strength) of treated and untreated mono and hybrid fiber combinations were evaluated based on their volume content in the ECC mix. The results showed that mercerized hybrid fiber combinations exhibited enhanced mechanical performance compared to untreated fibers. The ECC was then applied in the tension zone of an M30 grade structural beam to determine its load-carrying performance in this zone. Overall, the use of ECC with mercerized hybrid fibers has the potential to significantly improve the mechanical properties of concrete structures.

Investigation of the engineering properties of self-compacting mortar containing marble powder waste

Farih Messaoudi — 2025-09-03

The present research investigates the potential of using marble powder waste (MP), a byproduct of limestone, to build self-compacting mortar (SCM), with the goal of creating economic and environmental value by replacing cement with co-products and improving their handling and management. The aim is to improve the sustainability signature of cement-based materials in the construction industry. Five different mortar mix proportions, replacement of cement by MP at dosages of 0%, 10%, 20%, 30%, and 40%, are tested for slump flow, yield stress, viscosity, water absorption, bulk density, porosity, and compressive and flexural strength. The investigation delves into the influence of MP content on the rheological and mechanical properties. The results showed that the increase in marble powder led to an increase in both yield stress and plastic viscosity. Furthermore, the investigation found that a self-compacting mortar with a yield stress of 4.1 Pa at a 40% MP replacement rate and a viscosity of 2.9 Pa.s may achieve a slump flow of 242–351 mm. Furthermore, mortars containing 30% MP had a maximum compressive strength of 39.8 MPa at 28 days, which is a 7.4% increase over the reference mortar. Microstructure study showed that adding 30% MP improves mortar cohesiveness and densification. These findings demonstrate the potential of MP as a beneficial addition in SCM production, providing better performance and structural integrity. However, limitations in terms of specific application scenarios and long-term durability necessitate more exploration. Practical consequences include the potential for creative, sustainable, and cost-effective self-compacting concrete compositions, which will help to progress construction practices and environmental sustainability. Social consequences include the possibility for reduced environmental impact and increased resource efficiency in the construction industry. The results of the study provide an interesting insight into the possibility of using this kind of waste as a replacement for cement, thus reducing the demand for cement and the burden on landfills for disposing of such invasive waste from MP, and reducing the carbon footprint.

Comparison of types of protection applicable to bamboo-guadua structures for elements exposed to weathering

Liliana Rocío Patiño León — 2025-09-03

Bamboo has an important historical background in construction worldwide; however, at present, some construction practices are based on historical experiences, which, although they represent a great cultural value, show technical gaps that hinder the proper use, implementation, and preservation of the material. Therefore, this study seeks to contribute to the knowledge about the preservation of bamboo-guadua constructions through preventive maintenance against the action of atmospheric agents. This study documents the deterioration of bamboo-guadua samples, preserved and unpreserved, protected with 4 different commercial products and unprotected, unexposed, and exposed to weathering for 9 months, in order to compare their deterioration and behavior, as well as their pathological processes. The methodology used was to monitor the behavior of this material by means of a visual inspection through photographic documentation and analysis with a scanning electron microscope, which seeks to identify the changes in the surfaces of the exposed guadua, comparing it to unexposed elements. As preliminary results, it was found that the protected samples show similar deteriorations to unprotected samples, being lower in preserved samples than in unpreserved samples exposed to weathering. Also, it was found that protective treatments are not sufficiently effective against the action of atmospheric agents, and that the surface of the material, although it shows a change in color and cracks, does not necessarily indicate a loss of compressive strength. As well, the results of this study contribute to decision-making on the use of bamboo outdoors, the maintenance products to be used, the details of the deterioration at the dermis and epidermis levels, as well as the relationship between the presence of deterioration and the mechanical behavior of the material.

Evaluation of elastic failure criteria in numerical modeling of uniaxial compression test using the Edinburgh Bonded Particle Method

Angela Arriagada — 2025-09-03

The Edinburgh Bonded Particle Method (EBPM) can be used to represent a cementitious heterogeneous medium by spherical particles linked by bonds that break when any strength (tensile, compressive, and/or shear) is exceeded. Indeed, the controlling failure mode is associated with the first of these limit stresses that are exceeded. The main issue is that this elastic failure criterion ignores the fact that the bond breakage has a multiaxial nature. Given this issue, this work computationally implements two multiaxial stress failure criteria (Mohr-Coulomb and Zhou-Wu) to be employed in models using the EBPM. These implementations are used to simulate destructive unconfined uniaxial compression tests of cylindrical concrete specimens. The obtained results are also compared to the numerical results obtained by Brown and the analytical constitutive curve proposed by the Eurocode. From the analysis, it is concluded that the elastic failure criterion by Zhou- Wu achieves a better fit with respect to the analytical compression strength, being able to characterize the failure plane as well as simulate the propagation of cracks. The results also show that this approach can be useful to assess the behavior of granular materials with a cementitious matrix.

Effects of different loading types and high temperatures on the bending behavior of GFRP box profiles

Ferhat Aydın — 2025-09-03

The widespread use of fiber-reinforced polymer (FRP) materials in the construction industry is steadily increasing. While these materials possess numerous superior properties, it is well-known that their strength decreases under the influence of temperature. In this study, glass fiber reinforced plastic (GFRP) box profiles were first subjected to bending tests when they reached -30 to 200 ^oC. In the second, after reaching the target temperature, they were kept at the target temperature for 30-60 minutes and subjected to bending tests when they returned to room temperature. To investigate the effect of loading type, both three-point and four-point bending tests were conducted. Due to the temperature effect, the surface changes of the profiles were examined under a microscope. Finally, the compatibility of mathematical formulas with the experimental data was determined using correlation and regression analyses. The results of the study show a decrease in bending strength with increasing temperature, while an increase in bending strength was observed under cold conditions. It was found that exposure time had a more significant effect at lower temperatures, while at higher temperatures, thermal degradation dominated the failure mechanism regardless of exposure time. Additionally, it was observed that the loading effect is crucial, and therefore, both loading types should be considered.

The usability of construction and demolition wastes stabilized using alkali activated fly ash as filler material

Tacettin Geckil — 2025-09-03

Since construction and demolition waste (CDW) contain materials such as gypsum, wood, brick, plaster, etc., its engineering properties may not be at the desired quality. Therefore, if CDW is to be recycled and reused, the properties of CDW may need to be improved by various methods. In this study, the modifications in compaction and strength properties of CDW obtained from demolished building were investigated by adding fly ash (FA) at certain ratios. For this purpose, modified proctor, unconfined compression strength and California bearing ratio (CBR) tests were conducted on the CDW with and without FA-added. As a result of the experimental studies, it was observed that the addition of alkaline activator solution (AA) to the CDW increased the strength of the CDW. In addition, the strength of CDW increased significantly with the usage of AA in FA-added CDW samples. The FA additive ratio that gave the highest strength in the tests with water and AA was found to be 5% and 15%, respectively. As a result of the study, it is predicted that CDW with FA and AA can be used as a filling material as an alternative to natural aggregate.

Indoor light environment testing and simulation of improvement measures for traditional cave dwelling architecture

Dequan Kong — 2025-09-03

The indoor light environment in the traditional cave dwelling architecture that is still widely used today is generally poor, which seriously affects the comfort and health of residents. On-site measurements of indoor illuminance, daylighting coefficient, and illuminance uniformity parameters show that even under natural light at 12:00 noon, the indoor illuminance and daylighting coefficient of the cave dwelling are only 150.5 (lx) and 1.35%, respectively, and the uniformity of illumination is also poor, which must be improved to enhance the comfort and health of residents. By conducting simulation research for influencing factors (daylighting coefficient and window area, window sill height and glass transmission ratio, window-to-floor ratio) of the light environment in the cave dwelling with Ecotect Analysis software, the simulation results showed that the illuminance and daylighting coefficient of the kiln house during natural lighting were increased by 64.4% and 105%, respectively. However, the light uniformity is still low, and artificial light sources should be added as a supplement. The effect of surface-mounted artificial light sources was better, which could increase illuminance uniformity and mixed illuminance uniformity by 363.3% and 358.3%, respectively, ensuring the uniformity of indoor illuminance.

Recycling and multi-recycling high performance concretes as coarse aggregates for making new high-performance concretes

Abdessamed Azzaz-Rahmani — 2025-09-03

This research work aims at assessing the physical-mechanical properties of recycled and multi-recycled high-performance concrete as aggregates for making new high-performance concrete (HPC). Different concretes have been made with aggregate substitutions of 50%, 75% and 100% of recycled and multi-recycled high-performance concrete as coarse aggregates. A natural aggregate high performances concrete of around 75 MPa was first fabricated and then crushed to produce recycled concrete aggregates for making a first cycle HPC recycled aggregates concrete of 73 MPa. After assessing its properties, this concrete was in turn crushed to produce a second-cycle recycled HPC aggregate for making a two-cycle recycled aggregates HPC of 71 MPa. The results show that, after two cycles of recycling, HPC keeps almost the same physico-mechanical properties as the parent concrete, even when 100% of recycled concrete aggregates were used. The hardened recycled cement paste was as strong as the natural aggregates used or even stronger, since traces of crushed aggregates were observed. This has resulted in recycled HPC properties similar to those of the original high-performance concrete. Recycling high-performance concrete into coarse aggregates for making new high-quality concrete appears to be a valuable aggregate supply resource, which fully fulfills the challenge of sustainable concrete construction that responds to the quest for sustainable development.

Assessing the impact of infection rate on the productivity of re-sources in the construction industry: lessons from covid-19 pandemic

Mohamed Elsaid — 2025-09-03

Following the declaration of the coronavirus 2019 (COVID-19) outbreak as a pandemic, numerous countries decided to implement complete lockdowns in response to the global surge in cases. This decision significantly restricted people's movement and compelled businesses to shut down entirely. Most countries faced economic crises, and many firms laid off some of their employees. One of the economy’s significant growth drivers is the construction industry, which was also forced to a complete shutdown. Not only were they forced to shut down, but they also had to terminate some of the contracts for their upcoming projects. Many construction companies had to postpone their project until further notice, and then they decided to reduce the number of workers to diminish the probability of being infected by the virus. Consequently, it became essential to assess the pandemic's impact and develop an optimal strategy to maintain project continuity in the face of similar future pandemics. The aim of this study was to investigate and optimize the productivity of the construction crews to deal with any pandemic or similar unexpected circumstances. The study investigated the productivity related to different scenarios and determined what is the best scenario that will lead to the continuity of the project. These various scenarios were examined and compared through the use of the “AnyLogic” software program. The results reached demonstrated the impact of pandemics on the production rate of construction projects. The study demonstrated that employing only 60% of the required crew led to an additional 64 days of delay in the case study analyzed, whereas utilizing the full crew capacity allowed the project to be completed within just 100 days.

Impact of parent concrete strength of recycled aggregates on the mechanical performance of RAC bricks

Rashid Hameed — 2025-09-05

Natural aggregate and attached mortar are the two main components of the recycled concrete aggregates (RCA), therefore, compared to natural concrete aggregates (NCA), RCA generally have significant heterogeneity. Due to variation in their expected behavior as a result of heterogeneity, the use of RCA in concrete for various applications is still very limited. Since the properties of natural aggregates and adhered mortar in RCA are mainly dictated by the quality of their parent concrete, the careful evaluation of properties of RCA derived from waste concrete of different sources is always required before their possible use in concrete. Research studies in the past have revealed that the strength of parent concrete has always had a considerable impact on the physical and mechanical properties of RCA. In this study, RCA were produced from four classes of parent concrete with respect to their initial strength (i.e., 21 to 28 MPa, 28 to 35 MPa, 35 to 42 MPa, and above 42 MPa) and were used in the manufacturing of concrete bricks by replacing 100% NCA (fine and coarse) with RCA. Tests were performed to evaluate the effect of the parent concrete strength on the physical and strength properties of RCA, and the mechanical behavior of recycled aggregate concrete (RAC) bricks. For comparison, Natural Aggregate Concrete (NAC) and burnt-clay bricks were also tested. RAC and NAC bricks were manufactured using 10% cement and under a casting pressure of 35 MPa. Compressive, shear, and flexure strengths and impact resistance of bricks were determined using standard tests. The results showed that the physical and strength properties, and water absorption of RCA were improved with the increase in strength of their parent concrete. The water absorption of coarse RCA obtained from low-strength concrete (i.e., 21 to 28 MPa) was 4.8 times higher than that of NCA, whereas coarse RCA obtained from concrete with compressive strength above 42 MPa showed almost similar physical properties as those of NCA. For RAC bricks prepared with RCA obtained from high-strength parent concrete (i.e., > 42MPa), 11% improvement in compressive strength, 2.23% decrease in the flexure strength, and 6.6% increase in the shear strength were observed in comparison with NAC bricks. Compression, shear, flexure strength, and impact resistance of RAC bricks were found to satisfy the requirements of local and ASTM Standards and were higher than those of burnt-clay bricks. This study finally concluded that fully RAC bricks manufactured using RCA derived from old concrete having compressive strength greater than 21 MPa are not only structurally viable but are also environmentally friendly and could help to manage construction and demolition (CandD) wastes efficiently and beneficially.