The rising demand for infrastructure and rapid urbanisation has led to the increased use of cement composites, which are known for their extreme carbon footprint. This necessitates sustainable alternatives to traditional construction materials. Biochar (BC), a carbon-rich byproduct from biomass pyrolysis, has emerged as a promising additive or partial replacement in cement-based composites due to its dual benefits of performance enhancement and carbon dioxide (CO₂) sequestration. This study aims to evaluate the role of BC in cement-based composites through a scientometric analysis of over a decade of Scopus-indexed publications. The research investigates key questions regarding the types and production methods of BC, its influence on mechanical and durability properties of composites, environmental impact, and carbon capture potential. Using scientometric tools, the study maps global research trends, with China leading in publication volume, followed by India and Italy; the United Kingdom ranks 16th, indicating a research gap and opportunity for advancement in this domain. Findings reveal that incorporating 1–2% BC improves mechanical properties, while additions beyond 5–6% may lead to performance decline. BC enhances microstructural characteristics by promoting internal curing, pore refinement, and reduced shrinkage. Notably, BC’s carbon sequestration capacity distinguishes it from other sustainable materials, suggesting its potential to contribute to developing low-carbon or even carbon?negative construction materials. This research underscores the significance of BC-modified composites for sustainable construction and highlights the need for further investigation, particularly in the UK, to harness their full potential in reducing the construction industry’s environmental impact

Ultra-high-performance concrete (UHPC) is characterized by exceptional compressive strength; however, its structural performance is primarily governed by tensile behavior, fracture resistance, and energy dissipation. This study presents a comprehensive mechanical characterization of a steel fiber-reinforced UHPC incorporating a slag–limestone powder-based binder system with a low water-to-binder ratio of 0.15 and steam curing at 90 °C for 48 h. The experimental program comprised compressive strength, flexural behavior, split and direct tensile response, impact energy absorption, ultrasonic pulse velocity, and an assessment of specimen size and geometry effects. The UHPC achieved mean compressive strengths of approximately 209 and 218 MPa at 7 and 28 days, respectively, in 75 × 150 mm cylindrical specimens, indicating only modest strength development after the initial steam-curing period. Smaller cube specimens exhibited higher nominal compressive strengths, reaching approximately 221 and 227 MPa at 7 and 28 days, respectively, demonstrating a measurable but limited specimen-size effect. Flexural testing produced an average strength of 33.1 MPa and a stable post-peak response, although no strain hardening in bending was observed. Split tensile strength reached approximately 16.1 MPa, exceeding that of conventional normal-strength concrete by more than four times. Direct tensile tests demonstrated an intrinsically ductile response, with tensile strengths above 10.9 MPa and strain capacities of 0.25–0.30%, including a pronounced strain-hardening regime. Under drop-weight impact loading, specimens absorbed more than 40 J of energy without catastrophic fragmentation. Ultrasonic pulse velocity averaged 5344 m/s, indicating a dense and well-integrated microstructure. Overall, the results confirm that the investigated UHPC functions as a fracture-resistant structural composite in which tensile capacity, fiber-controlled crack bridging, and energy dissipation govern performance across multiple loading modes.

Concrete is one of the most consumed construction materials in the development of built infrastructure, with an annual production of about 30 billion tons globally. However, the production of Portland cement, which is a key ingredient of concrete and imparts strength and stability, has a significant carbon footprint; each ton of cement production is associated with 0.9 tons of carbon dioxide emission. Globally, cement production accounts for 7

This paper investigates the effects of powder waste glass (PWG) at 10%, 15%, and 20 wt.% replacement of cement on the flow characteristic, setting time, compressive strength, water sorption, rate of the heat of hydration, cumulative heat of hydration; alkali-silica reaction (ASR), and microstructure characteristics of the resulting paste and mortar mixtures. A total of eight cementitious mixtures including two control mixtures have been investigated in this experimental program to evaluate the effect of PWG on the fresh and hardened state characteristics of paste and mortar mixtures. Test results show that the incorporation of PWG in the cementitious mixtures results in significant enhancement of their microstructure, increase in compressive strength, improvement in moisture barrier characteristics, and considerable reduction in the rate of the heat of hydration and cumulative heat of hydration. Up to 20 wt.% replacement of cement with fine PWG is seen to be innocuous from the standpoint of ASR. Furthermore, the use of PWG in paste results in delaying the initial and final setting times and increases the flow characteristic of the mortar mixture.

Concrete is one of the most commonly used construction materials; however, its durability plays a pivotal role in areas where the concrete is exposed to severe environmental conditions, which initiate cracks inside and disintegrate it. Randomly distributed short fibers arrest the initiation and propagation of micro-cracks in the concrete and maintain its integrity. Traditional polypropylene fibers are thin and encounter the problem of balling effects during concrete mixing, leading to uneven fiber distribution. Thus, a new polypropylene fiber is developed by gluing thin ones together, forming macro-polypropylene fibers. Thus, different amounts of fibers, 0–1.5% v/f with an increment of 0.5% v/f, are used in different grades of concrete to study their impact on durability properties, including resistance to freezing and thawing cycles, sulfate, and acid attacks. A total of 432 cube samples were tested at 28, 56, and 92 days. The results reveal that the maximum durability, in terms of compressive strength loss, is noted with a fiber content of 1% with improved resistance of 72%, 54%, and 24% against freeze–thaw cycles, sulfate attack, and hydrochloric acid attack, respectively, at 92 days. Thus, the resulting fiber-reinforced concrete may be effective in areas where these extreme exposure conditions are expected.

AbstractConcrete is used worldwide as a construction material in many projects. It exhibits a brittle nature, and fibers' addition to it improves its mechanical properties. Polypropylene (PP) fibers stand out as widely employed fibers in concrete. However, conventional micro-PP fibers pose challenges due to their smooth texture, affecting bonding within concrete and their propensity to clump during mixing due to their thin and soft nature. Addressing these concerns, a novel type of PP fiber is proposed by gluing thin fibers jointly and incorporating surface indentations to enhance mechanical anchorage. This study investigates the incorporation of macro-PP fibers into high-strength concrete, examining its fresh and mechanical properties. Three different concrete strengths 40 MPa, 45 MPa, and 50 MPa, were studied with fiber content of 0–1.5% v/f. ASTM specifications were utilized to test the fresh and mechanical properties, while the RILEM specifications were adopted to test the bond of bar reinforcements in concrete. Test results indicate a decrease in workability, increased air content, and no substantial shift in fresh concrete density. Hardened concrete tests, adding macro-PP fibers, show a significant increase in splitting tensile strength, bond strength, and flexural strength with a maximum increase of 34.5%, 35%, and 100%, respectively. Concrete exhibits strain-hardening behavior with 1% and 1.5% fiber content, and the flexural toughness increases remarkably from 2.2 to 47.1. Thus, macro PP fibers can effectively improve concrete's mechanical properties and resistance against crack initiation and spread.

The use of fly ash as partial replacement of cement in the production of environmentally-friendly concrete is now an established fact. This study investigated the effects of class-C and class-F fly ash at 20 wt% replacement of Portland cement (PC) on the strength and durability characteristics of concrete mixtures incorporating crushed stone sand as fine aggregate. Experimental investigations were carried to compare the effects of class-C and class-F fly ash as partial replacement of cement on the rheology, compressive strength, moisture sorption, abrasion resistance, and microstructural characteristics of the resulting concrete mixtures at various concrete ages.

Reinforced concrete is used worldwide in the construction industry. In past eras, extensive research has been conducted and has clearly shown the performance of stress–strain behaviour and ductility design for high-, standard-, and normal-strength concrete (NSC) in axial compression. Limited research has been conducted on the experimental and analytical investigation of low-strength concrete (LSC) confinement behaviour under axial compression and relative ductility. Meanwhile, analytical equations are not investigated experimentally for the confinement behaviour of LSC by transverse reinforcement. The current study experimentally investigates the concrete confinement behaviour under axial compression and relative ductility of NSC and LSC using volumetric transverse reinforcement (VTR), and comparison with several analytical models such as Mander, Kent, and Park, and Saatcioglu. In this study, a total of 44 reinforced-column specimens at a length of 18 in with a cross-section of 7 in × 7 in were used for uniaxial monotonic loading of NSC and LSC. Three columns of each set were confined with 2 in, 4 in, 6 in, and 8 in c/c lateral ties spacing. The experimental results show that the central concrete stresses are significantly affected by decreasing the spacing between the transverse steel. In the case of the LSC, the core stresses are double the central stress of NSC. However, increasing the VTR, the capacity and the ductility of NSC and LSC increases. Reducing the spacing between the ties from 8 in to 2 in center to center can affect the concrete column’s strength by 60% in LSC, but 25% in the NSC. The VTR and the spacing between the ties greatly affected the LSC compared to NSC. It was found that the relative ductility of the confined column samples was almost twice that of the unrestrained column samples. Regarding different models, the Manders model best represents the performance before the ultimate strength, whereas Kent and Park represents post-peak behaviour.

Industrial development has generated enormous conveniences for humans at the cost of environmental pollution. Cement production is a major cause of carbon dioxide emission in the construction industry, and utilization of a large number of aggregates in concrete is causing scarcity of natural resources and irreversible depletion. The practice of utilizing industrial wastes in the production of concrete can be a useful solution. In this research, green concrete of enhanced properties is produced by incorporation of milled glass as partial replacement of cement, and fine aggregates are replaced by granular steel slag with different dosages. Ten types of concrete mixes substituting 10%, 20%, and 30% of cement by glass powder (GP) and 40%, 60%, and 80% of sand by granular steel slag (SS) were assessed in terms of rheological, mechanical, and microstructural properties. Results indicated that concrete having 80% granular steel slag and 20% glass powder shows a maximum increase of 42%, 16%, 16%, and 14% in splitting tensile strength, flexural strength, modulus of elasticity, and compressive strength, respectively. Scanning electron microscopy depicts the formation of secondary calcium silicate hydrate (CSH) and improved packing density in concrete mixes having granular steel slag and glass powder. Thus, granular steel slag and glass powder can effectively be used as cement and sand replacement in the production of value-added green economical concrete, reducing environmental pollution.

Pumice stone, known as the lightweight aggregate, is a mixture of lava and water used to replace coarse aggregate in construction. Nowadays, lightweight concrete has many applications in the concrete and construction industry. This study aims to overcome the project's cost and re-use the waste material dumped by the textile industry known as a pumice stone. Besides, an attempt has been made to compare the conventional concrete and lightweight aggregate concrete (LWAC) using a mix ratio of 1:1.5:3 and determine the strength parameters of LWAC. Lightweight concrete is made by partial replacement of coarse aggregate with different proportions of pumice stone ranging from 10%, 20%, 30%, 50%, 75% and 100%. Furthermore, several tests have been conducted to investigate mechanical properties such as compressive strength and tensile strength of lightweight concrete and compare them with conventional concrete. A total of 42 cylinders were cast and prepared, in which 21 cylinders were for compressive strength and 21 for tensile strength. Each set of 3 cylinders was cast for 10%, 20%, 30%, 50%, 75%, and 100%, making 21 cylinders for compressive strength and separate 21 cylinders for tensile strength with the same proportions. The experimental results show that the strength gradually decreases as the percentage of pumice stone increases. Therefore, up to 30% of lightweight aggregate as a partial replacement gives the desired compressive strength. Besides, the split tensile strength decrease when the percentage of pumice stone increases and gives the desired strength up to 30% replacement. Therefore, it is concluded that 30% replaced concrete can be effectively used for structural purposes, whereas 50%, 75%, and 100% can only be suitable for the non-structural members.

Due to good quality of soil in the Peshawar region (North-West of Pakistan) and the expertise of the local labors in brick's production, bricks of this region is more popular in the country and exported to different provinces of the country as well as to Afghanistan. There are approximately 450 brick kilns in Peshawar and their production per day/brick-kiln is around 75,000 bricks; hence the daily production is about 3.4 Million. This study examines the physical and mechanical properties of local earthen clay bricks and their production in Peshawar city. There is a lack of relevant data about the excellence of locally made bricks and the selection of proper bricks kiln for any intended use of suitable bricks. Initially, out of 450 brick kilns, the location of 254 were noted through the Global Positioning System (GPS) to represent their location on google map using their coordinates. However, the whole area was distributed in four zones from which 50 brick kilns were selected from all zones. The analysis shows that bricks from all the selected kilns have acceptable engineering properties fulfilling American Society for Testing and Material (ASTM C67) guidelines. The mechanical properties of 1st class bricks have large variability, showing less porosity (19%), high compressive strength (CS) up to 24.27 MPa, and low water absorption (WA) rate of 11.9%. The CS of 1st class bricks was 56.73% greater than the standard CS whereas, it was 46.2% and 38.88% greater in case of 2nd and 3rd class bricks, respectively. A strong correlation was found in CS and WA, which was 76.83% in 1st class bricks and 77.44% and 85.29% in the 2nd and 3rd class bricks. Using Quantum Geographical Information System (QGIS), the results obtained along with kiln coordinates and other required parameters have been presented graphically. Inventory of the brick kilns for the selected zones has been developed using QGIS, which can be used by various relevant departments, contractors, and environmental protection agencies.

Closed-loop supply chain networks are gaining research popularity due to environmental, economic and social concerns. Such networks are primarily designed to overcome carbon footprints and to retrieve end of life products from customers. This study considers a multi echelon closed-loop supply chain in the presence of machine disruption. A multi-objective model is presented to optimize the total cost, the total time and emissions in a closed-loop supply chain network. The aim is to analyze the trade-off between the objectives of cost, time, and emissions and how these decisions are impacted by the selection of different available machines. A number of solution approaches are tested on a case study from the tire industry. The results suggest the improved performance of the hybrid heuristic and the importance of controlling disruption in a closed-loop supply chain network. Furthermore, there is a trade-off between the different objective functions which can help the decision maker to choose a particular solution according to the preference of an organization. Finally, conclusion and future research avenues are provided.

The obstruction offered by the surrounding concrete to the pulling out of embedded steel bar is known as bond strength. Steel fibers addition to concrete improves its bond strength by arresting the cracks due to their bridging effect. Bond failure occurs when cracks in the surrounding concrete initiates, providing enough space for bar to be pulled-out. Micro steel fibers efficiently control the formation of micro cracks and may improve bond strength to a greater extent compared to the longer steel fibers. However, it reduces the workability of concrete which is of greater importance in case of self-compacting concrete (SCC). Reduction of workability is less pronounced when straight micro steel fibers are used due to their shorter lengths and straight geometry. Thus, different amount of straight micro steel fibers (0.25 %, 0.5 %, 0.75 %) were incorporated in to SCC to investigate their fresh and mechanical properties with major emphasis on the bond strength. Results indicate that steel fibers addition to SCC improve the splitting tensile strength and bond strength significantly with a maximum increase of 33.5 % and 54.9 % respectively with 0.75 % fibers addition. An equation is proposed for the calculation of bond strength with micro steel fibers addition to SCC with a maximum variation of 4 % to those of experimental values.

Concrete is weak in tension and fibers are added to it to make it ductile. One of the commonly used methods, for this purpose, is the addition of steel fibers of different geometries. However, failure of fiber reinforced concrete is initiated by pulling out of fibers, failing to utilize their full capacity. In this study, closed steel fibers (CSF) are proposed for addition into concrete. The objective was to avoid the pulling out of fibers in tension for full capacity utilization. When CSF are embedded into concrete, they are expected to reach the breaking point, utilizing their maximum capacity due to the presence of concrete matrix within the closed geometry of fibers. Different volumes of straight steel fibers (SSF) and CSF were used to investigate and compare their performance. Fresh and hardened concrete properties were considered. Results indicated decrease in workability of fiber reinforced concrete with increasing steel fiber content. No significant change in concrete compressive strength and modulus of elasticity was noted. There was a maximum of 46% increase in tensile strength while 36% increase in flexural strength of concrete with the use of CSF compared to that of SSF. The failure of concrete in tension was initiated by pulling out of open fibers and breaking of closed fibers. Thus, use of closed steel fibers is recommended to make full use of steel fiber tensile capacities which may revolutionize the field of fiber reinforced concrete.

The only type of conventional bitumen (PG 64-10) available in the Kingdom of Saudi Arabia (KSA) does not meet the temperature requirements of most of the kingdom’s regions. Hence, the binder needs to be modified to improve the performance of flexible pavements at high temperature and heavy traffic loading. In order to meet the requirements of the Superpave Performance Grade (PG), crumb rubber (CR), epolene (EE-2), and date palm ash (DPA) were used as asphalt additives in different percentages (4%, 8%, 12%, and 16% by weight of bitumen). Viscosity and rheological tests as well as stability and indirect tensile tests were performed on binders and asphalt mixtures. The binders modified with CR, EE-2, and DPA showed improved rheological and performance properties as compared to conventional binder. Similarly, the PG of conventional asphalt was upgraded with the addition of different percentages of the modifiers. Furthermore, this study also aimed to help the environment by minimizing and recycling wastes in road construction processes to achieve sustainability.

Mortar is used all over the world for construction purpose.It consists of cement paste and fine aggregates and admixtures if required are also incorporated to modify some of its properties.In this study coconut fibers and human hair were used as an additive materials in the mortar and its effects on compressive strength of the mortar were investigated.Coconut fibers and human hair are waste materials which are produced in millions of tons every year which create not only biodegradability problems but also cause pollution.Coconut fibers and human hair were used as additive materials in mortar in 2, 4 and 6 % to prepare blended mortar.Mortar samples of coconut fibers and human hair were prepared and compared with each other and control samples.Cement to sand ratio was kept 1:3 with water cement ratio of 0.6 for all mixes.Cubes having dimensions of 2×2×2 inches were used in this project.All the mixes were cured at normal room temperature for 3, 7 and 28 days.Results revealed that mix with 4% coconut fibers showed higher compressive strength at 3 days and 6% higher compressive strength at 28 days.With increase of coconut fibers compressive strength increased.However, mortar with human hair initially shows higher strength when 2 % was incorporated but with increasing percentage of human hair, strength was reduced.With addition of mix fibers i.e. coconut fibers and human hair into the mix, the compressive strength initially increased at 3 rd day of curing, showing higher compressive strength at 3 days for all percentages of mix compare to reference mortar, however with further increase of percentage of mix fibers into the mortar, the compressive strength was reduced showing lowest compressive strength at 28 th days for 4% of mix fibers i.e. coconut fibers and human hair.

Atterberg Limits were initially defined in 1911, by Albert Atterberg, a Swedish scientist. Their purposes are to classifying cohesive soils and determine engineering properties of soils. According to ASTM, all the soils tested by Atterberg limits should be oven dried, it is because drying the soils in different degree will alter their properties significantly. Some of the physical properties of soils will undergo changes that appear to be permanent. Therefore, the soil samples should be in natural or air-dried form. However, in reality, due to time constraint and other factors, many will run the tests by using soil samples that are prepared by oven drying method. They assumed that there is no difference between the results of two types of drying method. However, in reality, the properties of soil will be affected and thus give a misleading result. The objective of this study is to determine the effect of two drying methods, air-drying method and oven drying method, on the soil plasticity. Six soil samples from different cities were tested. These tests include sieve analysis, specific gravity test, hydrometer analysis, Plastic limit and liquid limit test. Conclusively, the oven drying method could not replace

Health aspects enforced to ponder a study on asphalt which incorporate rubber crumbs to increase strength and flexibility of asphalt. Disposal of waste tires is a menace and it’s a serious problem globally because it is not easily biodegradable as these tires consume large spaces, open burning cause serious problems. By the use of rubber tires, this scrap is utilized efficiently and reduces the cost of asphalt to produce economical system. The asphalt is absorbed by the rubber particles which swells at high temperature allowing greater concentration of liquid asphalt. The partial replacement of crumb rubber in asphalt is 5%, 10%, 15%, and 20% (D05, D10, D15, and D20). The analysis of incorporated asphalt was done in hot mix asphalt. The generated results showed that the value for resilient modulus and creep stiffness is more as compared to the conventional asphalt and in the accumulated strain the values are much lesser which is positive approach.