Regular Concrete Research Articles

Impact of partial substitution of sand by compost on the mechanical and thermal parameters of concrete

The study investigates recycling organic waste in Algeria due to the rising use of natural resources and energy in concrete production and the large amount of organic waste discarded. The aim is to use compost as a partial replacement for sand, reducing the use of natural aggregates in the concrete industry while also reusing previously discarded waste as part of a circular economy. An experimental study was carried out on concrete’s thermal and mechanical properties to determine the effect of partial compost replacement on these properties. Five mixtures were created by replacing sand with compost in different proportions: 0, 5, 10, 15, and 20%. Slump and density were assessed in the formulations’ original state. Mechanical tests were performed on the hardened concrete to determine porosity, compressive strength, and flexural strength. Thermal tests were also conducted on various types of concrete to determine thermal conductivity. The findings show that the texture of the compost reduced the slump, highlighting the importance of incorporating an admixture to achieve the desired workability. While meeting normal-weight concrete standards, concrete density was reduced. The mechanical properties of concrete with small amounts of compost were similar to regular concrete; instead, waste porosity improved insulation.

The Uses of Lightweight Material in Civil Engineering : A Review

A lightweight aggregate (LWA) is a group of aggregates with a relative density lower than normal density aggregates (natural sand, gravel, and crushed stone), sometimes referred to as low density aggregate. It is utilized for its reduced weight and exceptional qualities in sound reduction, fire resistance, insulation, and geotechnical applications LWA, or lightweight aggregate, is a cutting-edge construction material that is employed to decrease the overall weight of tall structures. Despite being lighter, it possesses a strength that is comparable to that of regular concrete. In recent times, there has been a significant surge in the use of lightweight aggregate in the field of building, mostly because of its exceptional performance in seismic situations. In addition, substituting natural aggregate with other industrial by-products and trash enables us to minimize the adverse environmental consequences. Laser wavelength ablation (LWA) has also been employed to address a wide range of geotechnical engineering challenges, including the transformation of soft and unstable soil into a suitable and usable property. Lightweight fillings have a weight that is around 50% less than fills made using typical materials. The load reduction, along with the high internal friction angle of the lightweight aggregate, can decrease vertical and lateral pressures by almost 50%, potentially resulting in less settling. This literature study examines the use of lightweight materials, including LECA, Bonza, and Thermostone, in geotechnical engineering applications. The results demonstrate a significant emphasis on improving slope stability and minimizing stresses on susceptible soils. Nevertheless, several knowledge gaps exist regarding the efficacy of these materials under challenging conditions and when subjected to dynamic loads. A growing inclination towards using these lightweight aggregates is observed because of their advantageous environmental and mechanical properties. Further investigation is needed to examine the extended-term performance and interactions of these materials with different soil types in order to enhance their performance in diverse geotechnical situations.

Influence of Recycled Coarse Aggregate and Steel Fiber on the Workability and Strength of Self-Compacting Concrete

Abstract Waste materials pose a significant threat to both the environment and human health. On a global scale, the quantity of recyclable material is steadily growing, and its proper disposal is a significant focus of modern study. Concrete debris is a recyclable material that poses challenges for reutilization. Concrete waste refers to the fragments or remains of ready-mix concrete plants and the debris from destroyed structures, including historic buildings and those affected by earthquakes. The objective of this study is to reuse and utilize coarse aggregate formerly used in concrete constructions to create self-compacting concrete (SCC). The purpose is to assess the performance of this recycled aggregate in both its fresh and hardened states. Natural coarse aggregate (NCA) was switched out for recycled coarse aggregate (RCA) at 0, 50, and 100% volume ratios. In contrast, concrete was mixed with steel fibers (SF) at volume percentages of 0 and 0.44. Workability tests, including V-funnel, slump flow, and L-box tests, were conducted to assess the consistency of the mixes in their fresh condition. Additionally, the tensile and compressive strength of the concrete specimens were measured to evaluate their strength in the hardened state. Overall, the experimental findings showed that the fresh qualities of almost all SCC mixes fell within the required range, as outlined in the EFNARC standards. While the steel fiber harmed the fresh characteristics, it resulted in a proportionate enhancement in tensile strength. The findings indicated that including recycled aggregates into the concrete mixture enhanced its strength. The results showed that adding (0.44%) of steel fibers to concrete reduced the decline in compressive strength when the coarse aggregate was replaced entirely with recycled aggregate. In contrast, an equivalent proportion of fibers resulted in a significant improvement in tensile strength, rising from 26% to 54%, when using recycled coarse aggregate as the replacement of natural coarse aggregate. Thus, it can be concluded that using recycled aggregates and steel fibers in concrete production results in a higher quality product than regular concrete. Removing concrete waste has other benefits, such as enhanced financial return and preservation of the environment.

Corrosion effects on bond strength in reinforced concrete with fly ash

Reinforcing steel bars provides additional strength and ductility to concrete by forming a strong bond with the concrete matrix. Corrosion of steel bars can significantly reduce the bonding effect between the steel bar and concrete, which can compromise the structural integrity and durability of reinforced concrete structures. An experimental investigation was performed to examine the influence of fly ash (FA) and corrosion on concrete–steel bond behavior. The accelerated corrosion method was employed to obtain the desired level of corrosion. The FA content, corrosion percentage, and presence of stirrups were considered significant factors influencing bond behavior. The bond–slip curves and bond toughness were used to discuss bond behaviors. The findings indicated that mild corrosion (below 2.5%) can enhance concrete–steel bond performance, and the addition of 20% FA leads to higher ultimate bond strength (τu ), significantly mitigating the decrease in bond strength caused by severe rebar corrosion. Also, this study analyzed the influence of stirrups on the bond strength of FA concrete and had a nearly insignificant effect compared to regular concrete. The results and discussions of the present study carry significant importance in the establishment of a bond–slip constitutive model under multifactor coupling conditions. Furthermore, it offers valuable insights into the design of engineering structures.

An Experimental Study on Mechanical Properties of Concrete by Partial Replacement of Cement with Graphene Oxide

Abstract: An essential building material, concrete is always changing for increased sustainability and performance. This study looks into the effects of replacing some of the cement in M60 grade concrete with graphene oxide. One amazing nanomaterial that is available in powder, sheets, flakes, and oxide form is graphene oxide. It has lately been used in the building industry and is robust, elastic, and lightweight. It has excellent qualities that are advantageous in the building industry. Adding graphene oxide to concrete composites improves binding strength to concrete structures, lowers permeability, and speeds up the pace of hydration. The concrete samples are tested for slump, split tensile strength, compressive strength, flexural strength, and durability after seven, twenty-eight, and fifty-six days. Graphene oxide concentrations in concrete compositions ranging from 0.5% to 2% by cement weight. The findings demonstrate that adding graphene oxide to concrete enhances its strength, with some mix compositions exceeding regular concrete. The mechanisms producing the strength increase are illuminated by the analysis of the experimental data, underscoring the potential of these additional components to enhance the durability as well as sustainability of concrete structures. These discoveries advance the field of construction material engineering by contributing to ongoing attempts to create high-performance and sustainable concrete compositions.

A Comparative Study between Special Concrete and Conventional Cement Concrete in Bridges and Precast Structures

Abstract: India is growing fast, especially in construction. Transportation is key for the country's progress. Bridges and elevated roads are crucial for smooth traffic. They need strong concrete to bear heavy loads for years. Regular concrete isn't always strong or long-lasting enough. This paper aims to make bridges and precast structures stronger, last longer, cost less, and be more eco-friendly. It compares normal concrete with special concrete. Special concrete has extra stuff like micro silica, polypropylene fiber, and bacillus subtilis. These boost concrete's strength and durability. The paper looks at how adding these things affects concrete's strength, how much water gets through it, and its tensile strength. Tests on different types of concrete show that special concrete is much better than regular concrete. This study looks closely at these special ingredients and how they make concrete better. It shows how each one helps concrete become stronger, last longer, and improve overall quality.

Strength Evaluation of Concrete using Over burnt Brick Stone as Replacement of Coarse Aggregate

Abstract: This research highlights on the behavior of concrete, prepared by the partial replacement of regular aggregate with over-burnt brick aggregate (jhama brick) with a replacing percentages of 0% , 35, 50% & 60% over M20 Grade of concrete which reduces the cost of aggregate (upto 30%) with higher strength, which also results in overall cost in building too .The effect of compressive strength, split tensile strength and flexural strength were reported . The received compaction factor is 0.92, 0.89, 0.88, and 0.87 with varying percentage of (0%, 35%, 50%, 60%) Jhama class brick respectively. This research was conducted to study the suitability crushed over burnt bricks as alternative course aggregates for concrete production. The compressive strength of this concrete is found to be 27.12 , 30.41, 26.02, 23.31 for 0%, 35%, 50%, 60% respectively. The concrete cube, beams and cylinders of M-20 grade were thrown in this trail, explore work and try to analyze different properties of concrete with crushed over burnt bricks as an alternative material. The result shows that the aggregate in concrete derived from Over Burnt bricks aggregate attained relatively higher strength upto the certain percentage and decreases after that, than the regular concrete. More detailed and elaborated work is recommended with different mix ratio and a different proportion of Over Burnt aggregates for a better conclusion.

Effects of Over-burnt Bricks on Gradation, Water Absorption and Specific Gravity of Aggregates, Workability and Compressive Strength of Concrete

Demand of bricks is increasing day by day by the requirement of new structures. Due to manufacturing of bricks, over-burnt bricks are also made. Generally over-burnt bricks are the waste materials which is generally used for dumping purpose and sometime it is thrown in useful land that create social and environmental problems. Therefore, this material should be properly treated, recycled and used in concrete as coarse aggregate. In this research work, six (06) batches were made with 1:2:4 mix and 0.5 water cement ratio. Each batch consists of five (05) samples. Six (06) batches were made with 0%, 20%, 40%, 60%, 80% and 100% replacement of natural coarse aggregates with over-burnt bricks aggregates. The outcome of study reveals that the gradation of both the aggregates shows same pattern and the trend of curve was almost similar, with minor difference in range values over a sieve. The water absorption of over-burnt bricks aggregates was more than the water absorption of natural coarse aggregates and the specific gravity of over-burnt bricks aggregates was less than the specific gravity of natural coarse aggregates. The result of slump test shows that there was continuous decrease in workability of concrete mix, as replacement of over-burnt bricks aggregates increased. 30 concrete cubes of (6” x 6” x 6”) size were prepared and cured for 28 days followed by compressive strength. The result shows that the concrete derived from over-burnt bricks aggregates attained lower compressive strength than the regular concrete. However, the values obtained from over-burnt bricks aggregates are still acceptable, especially for reasonable levels of the replacement ratio up-to 60%. This concrete can be used in new constructions, but it is proposed to be initially utilized in low load areas.

Effects of Glass Fiber on a Mechanical Properties of Concrete

The purpose of the study is to find out how adding glass fiber to concrete can improve its mechanical qualities. It assesses qualities including compressive strength, flexural strength, and strength and contrasts glass fiber-reinforced concrete (GFRC) with regular concrete. Tests on concrete samples with different glass fiber contents reveal that higher fiber content enhances ductility and flexural strength. Environmental pressures like chemical attacks and freeze-thaw cycles are not able to break down GFRC. Tests are enhanced by finite element analysis (FEA), which shows the distribution of stress and strain in the composite. In general, the research advances our knowledge of how GFRC may fortify concrete constructions, perhaps leading to the development of more robust building frameworks.

The Effect of Using Sustainable Copper Fiber on Some Mechanical Properties of High Strength Green Concrete

Finding an alternative to materials that pollute during manufacturing, most notably cement, is vital to executing the idea of sustainability in the building sector. It was vital to develop concrete that assists in the reduction of CO2 (Carbon dioxide) in the atmosphere because industrial wastes contain calcium, silica, and aluminous minerals, such as silica fume, that are employed in the production of high-strength concrete and have parameters that are identical to those of regular concrete. As a substitute for Portland cement, lime cement was utilized, and 15% of the cement's weight was substituted with silica fume. Environmentally friendly fibers (Copper Fiber) created from old electrical and electronic equipment were also employed. The purpose of the study is to produce High Strength Green Fiber Concrete (HSGFC) by incorporating silica fume as a replacement and study the effect of adding fiber on some mechanical attributes. The task needed the creation of a high strength concrete mixture of cement with a compressive strength of 65 MPa in accordance with ACI 211.4R, as well as the development of numerous experimental mixtures that relied on the findings of earlier researchers. The mechanical properties (compressive strength, flexural strength and split tensile strength) of samples are tested at 7, 28 and 60 days with standard curing. The results show that adding sustainable fiber to concrete mix enhances the mechanical properties such as compressive strength by 16% at 28 days, flexural strength by 35% and spilt tensile strength by 44% at 28 days Compared with concrete mix with no fiber. Also, the outcomes showed that it is feasible to develop High Strength Concrete (HSC) using sustainable copper fiber possessing exceptional stress resistance, tensile strength, and flexural strength.

Investigations on Blast Performance of Steel-Concrete Composite Structures

Blast performance of concrete and ultra-high performance fiber concrete (UHPFRC) has been subject to numerous publications in the past decades. The enhanced force-deflection diagram of fiber concrete and ultra-high performance fiber concrete provide massive increase on the protective function of these materials compared to regular concrete. Nevertheless, concrete spalling cannot be fully avoided even when using UHPFRC. The next step for harmful debris ejection prevention can be supplementing the concrete specimens with steel slabs. The steel slab will not just hold the debris, but can, if properly bonded with concrete, contribute to the load bearing capacity as steel-concrete composite structure. This paper presents an overview of recent experiments on blast resistance of steel-concrete composite slabs. In total 6 pairs of specimens (dimension 1.000/1.000/150mm) were prepared, 6 specimens using regular concrete and 6 specimens using UHPFRC. One pair of specimens was reinforced by a steel mesh at 30mm cover from the soffit, one pair was supplemented by a steel plate bonded with 4 studs in the corners, at the complementary specimen pair, the concrete was also covered with a steel plate at the side subjected to blast loading, in the case of the further pair of specimens, the steel plates were connected by steel bars arranged in a mesh 150/150mm. The final 2 pairs represented steel-concrete composite slabs, in the first case, the shear studs were supplemented with a steel mesh (according to provisions of the European standard for steel-concrete composite structures), in the last case, the shear studs were replaced by a shear plate. All specimens were subjected to the same contact blast loading. The paper presents the experimental arrangement, the achieved results and a brief discussion on the structural behavior.

Enhancing load prediction for structures with concrete overlay using transfer learning of time–frequency feature-based deep models

This study proposes a method to predict applied loads on bonded structures via non-destructive testing results. Various types of concrete, such as high-performance alkali-activated slag concrete (HPAASC) and regular Portland cement concrete (OPCC) are simultaneously tested via ultrasound testing and bi-surface shear for extracting features and target values, respectively. Variational Mode Decomposition is employed to extract useful features from ultrasound signals. In the first part, selected features using a PCA-based method are utilized to train a set of deep-learning models to estimate the imposed mechanical load on the tested specimens. The most effective models from the first step, i.e., a CNN-LSTM model and LSTM models, are then fine-tuned in the second step to estimate loading conditions in another set of specimens. Results indicate the superior performance of the CNN-LSTM model. The proposed algorithm highlights the effectiveness of ultrasound features in accurately evaluating structural loading conditions for efficient monitoring of various structures.

A REVIEW OF STEEL SLAG AS A SUBSTITUTE FOR NATURAL AGGREGATE APPLIED TO CONCRETE COLUMNS

There are severe ecological imbalances from both carbon emissions and sand mining. Steel slag can be used as an aggregate in concrete to enhance the environment and conserve natural resources because of the impact of depleting resources. The paper's main aim is to investigate the appropriateness of steel slag as an aggregate substitute and determine its impact on the behavior and durability properties of columns subjected to various circumstances and loads. After discussing slag and its properties, its effects on plain concrete were reviewed, followed by its effects on concrete columns. Previous studies indicate that columns made with steel slag aggregate concrete have comparable initial stiffness, strength, and flexibility as regular concrete. For columns with fine steel slag aggregates, the conventional section design approach can be used as an option for the design method. The European standard for stub columns filled with steel slag aggregate concrete under compression is more accurate than the American standard, which is circumspect.

Study on the durability of polyvinyl alcohol fiber reinforced concrete constructed by mixing - casting and mixing - spraying technology in seawater

Polyme fiber-reinforced concrete, with many superior features has solved some limitations of regular concrete. However, polyme fiber reinforced concrete to ensures long-term durability in sea water environments, it is necessary to combine many factors such as quality requirements material, durability and production technology of concrete,... This paper presents the experimetal results on the influence of durability (flexural strength, compressive strength) of polyme fiber (used polyvinyl alcohol fiber – PVA) reinforced concrete using mixing - casting and mixing - spraying technology in sea water environment. The experimental results show that PVA fiber reinforced concrete has the same strength development as normal concrete in both normal water and seawater. The strength of PVA fiber reinforced concrete cured in seawater environment at long-term ages (90 and 180 days) lower than that cured in normal water is 4.5%.

The performance of steel fiber reinforced concrete as structural elements of a seismic resistant three-story low-cost housing using SAP 2000

Seismic activity is a looming threat in many regions around the world. Hence, pursuing low-cost housing solutions that can withstand seismic forces while remaining economically viable is critical. This research is motivated by the urgent necessity to create innovative materials and cost-effective design methodologies that can withstand the forces of devastating earthquakes. This study explores the effectiveness of steel fiber reinforced concrete (SFRC) as a structural element in a three-story low-cost housing building. SFRC incorporates small and hooked steel fibers into concrete, improving its mechanical properties, such as tensile strength, toughness, and ductility. This study aims to replace traditional reinforced concrete with SFRC in building columns and beams and assess its seismic performance using Finite Element Method (FEM) analysis conducted through SAP 2000 software. This study conducted experiments using concrete mix samples with different percentages of steel fibers (0%, 0.3%, 0.5%, and 0.7% by weight) and found that the 0.3% SFRC sample exhibited the highest compressive and flexural strength. Four models evaluated the cost-effectiveness of SFRC compared to the control sample with regular concrete. The analysis revealed that Model (3), featuring 250 x 300 mm columns with SFRC, significantly decreased concrete volume and rebar quantity. It resulted in a 13.79% reduction in structural costs compared to the original plan. Overall, the study highlights the potential of SFRC to enhance the mechanical properties of concrete and reduce costs in seismic-resistant construction projects. By incorporating SFRC, engineers can improve buildings' structural stability and performance, particularly in earthquake-prone regions.

Effect of Recycled Concrete Aggregates, Sisal Fibres, and Carbon Nanofibres on the Mechanical Properties of Concrete

This research examines the mechanical properties of concrete by combining recycled concrete aggregates (RCA) with carbon nanofibers and natural sisal fibers, in place of natural aggregates. We created a variety of concrete mixtures with RCA content levels of0%,50%, and 100%, as well as varied fiber combinations. Some mixes included additional cementitious elements such as fly ash (FA) or silica fume (SF). Mechanical tests such as compressive strength, flexural strength, and split tensile strength were used to assess the performance. Findings shown that mechanical properties were significantly enhanced by using sisal and carbon nanofibers. Combine A9, which omitted RCA but included 1% sisal fiber and 0.2% carbon nanofibers, had the highest compressive strength (81.2 MPa), flexural strength (8.84 MPa), and split tensile strength (6.60 MPa). Using 100% RCA replacement (Mix C9) lowered the strength somewhat, however the mix still performed better than regular concrete. Based on the findings, RCA and sustainable fibers may be used into concrete to provide a greener alternative without compromising durability.

Mechanical Response Analysis of Regular and Lightweight Concrete under Bending Stresses

This study investigated the mechanical response of regular and lightweight concrete under bending stresses. We compared the stress‐strain relationships, densities, and deformation capacities of these two types of concrete to highlight their key differences. Lightweight concrete, with a lower density of 1800 kg/m³, offers significant weight reductions, making it ideal for applications with weight constraints. However, this reduced weight results in lower compressive and flexural strengths. On the other hand, normal concrete, with a density of 2400 kg/m³, exhibited higher mechanical strength and durability. The stress‐strain graphs from the study showed that both concrete types exhibit both elastic and plastic deformation, with a transition from elastic to plastic behavior at specific stress points. By balancing weight reduction against mechanical strength, this study provides valuable insights for construction professionals in selecting the appropriate concrete type for various projects.

Experimental Investigation on Silica Fume and Metakaolin in Self-Curing Concrete

Concrete is an example of a composite material that has become an essential component in the building and construction sector. Using pozzolanic materials like fly ash, silica fume, blast furnace slag, and metakaolin is being tested as one method of increasing the durability of concrete. The effect of cement that has serious negative impacts on the environment can be eliminated by using this additional cementitious material. In this investigation, an effort has been taken to examine the strength characteristics of concrete mixtures of M20 grade with cement partially replaced by metakaolin and silica fume and with all of the fine aggregate replaced by M-sand. To replace traditional curing, polyethylene glycol 6000 is used as a self-curing agent. Metakaolin is substituted at a rate of 5%, 10%, 15%, and 20% by weight of cement, while silica fume is substituted at a rate of 5%, 10%, and 15%, respectively. Self-curing concrete is created by adding 1.5% polyethylene glycol 6000 to regular concrete. The mortar cubes (1:3 ratio) are used in this project because it focuses on replacing the cement and fine aggregate. To study the mechanical properties of the concrete, cubes, cylinders, and prisms will be cast from the ideal percentage and tested.

Mechanical And Physical Properties Of Steel Fiber Secure Self-Compacting Bituminous Concrete Mix With Structural Elements.

The progression of Self Compac-ting Con-crete is dynamic accomplishment all through the entire nearness of progress industry acknowledging unprecedented usage of SCC all things considered these days. It has different focal concentrations over regular Con-crete the degree that improvement in item ivity, decrease in labor and generally cost, impressive completed thing with unprecedented mechanical reaction and quality. Mix of strands further updates its pro-perties strikingly identified with post split direct of SCC. Along these lines the reason for a near assessment solid, re-in-constrained with various sorts of filaments. The components join into the evaluation are type and contrasting degree of strands. The fundamen-tal properties of new SCC and mech-anical properties, quality, break importance and sorptivity were investigate ed. Micro_structure assessment of different blends is done through checking electron enhancing instrument to take a gander at the hydrated structure and security progress among fiber and blend.

A Study on the Mechanical Properties of Alkali Activated Concrete Using Various Types of Synthetic Zeolites

Abstract -The world's most common man-made material is concrete. Portland cement is a key component of a typical concrete mix. However, about 5% of the world's carbon dioxide emissions are brought on by the manufacture of cement. Engineers and scientists need to invent and use a green building material to make the world more sustainable. Due to its corrosion resistance, geopolymer concrete is also significantly more durable than regular concrete. It is also significantly stronger than regular concrete. The development of green construction will be facilitated by the innovative sustainable building material known as geopolymer concrete. Alkali- activated materials also known as geopolymers, are made from a variety of materials (usually industrial byproducts) known as precursors. These are combined with an alkaline medium to create a cementitious material that can be used in place of Portland cement in the production of concrete. Mineral admixtures (such as fly ash and GGBS) are typically added in larger amounts in concrete to improve its workability, resistance to thermal cracking, alkali-aggregate expansion, and sulphate attack, and to allow for a reduction in cement content. In the current study, sodium hydroxide and sodium silicate were used as alkaline activators with a Molarity of 12M, and fly ash, GGBS, and types of synthetic zeolites as binder ingredients. 40% of GGBS is kept constant and fly ash is replaced with zeolite in various percentages. In this paper, zeolite is replaced with 5%, 7.5%, and 10% of fly ash to create geopolymer concretes. Zeolite powder obtained by the calcination process with the aid of sodium hydroxide and fly ash, industrial wastages. The performance of the created concrete is then evaluated using mechanical behavior on developed mix. Key Words: Alkali activator, fly ash, Ground granulated blast- frunace slag, synthetic zeolites, strength properties.