Conventional Concrete Materials Research Articles

A Comparative Cost Analysis and Environmental-Mechanical Assessment of Conventional and Sustainable Concrete and Steel Reinforcement Materials

A Comparative Cost Analysis and Environmental-Mechanical Assessment of Conventional and Sustainable Concrete and Steel Reinforcement Materials

Waste valorization: Sustainable geopolymer production using recycled glass and fly ash at ambient temperature

This research explores the reutilization of waste glass powder (GP) and class F fly ash (FA) in the development of an advanced geopolymer, focusing on reducing natural resource consumption to serve as a green alternative for conventional concrete material. Investigating mix ratios of GP-to-FA (0-to-1), activated with 2–12 M NaOH, followed by ambient temperature curing, this study mainly assesses strength (compressive, and flexural) and durability at different ages. Mechanical properties concerning reaction kinetics and Al/Si ratio, reveal that GP initially acts as an inert filler with slow reaction kinetics, while significant strength improvement at later ages is attributed to the reaction between GP and FA. Optimal performance is achieved with a geopolymer mixture featuring a GP-to-FA ratio of 1:3 (Al/Si ratio of 0.51) and an 8 M NaOH solution, resulting in the highest compressive strength of 40 MPa and superior durability. Microstructural analysis (SEM-EDS, and 29Si MAS NMR) identifies the reacting product as calcium/sodium aluminate silicate hydrate (C/N-(A)-S-H) gel within the geopolymer matrix. Leaching tests further underscore potential environmental concerns related to excessive alkali leaching, necessitating meticulous mix design management. Embodied energy and carbon footprint assessments confirm the environmental friendliness of the GP-FA-based geopolymer. Overall, this research demonstrates the feasibility of producing effective geopolymers from dry waste at ambient temperature, emphasizing the potential synergy between waste glass recycling and the concrete industry towards sustainable construction practices.

On the computational evaluation of carbon dioxide emissions of concrete mixes incorporating waste materials: A strength-based approach

In the last decades, the high emissions of carbon dioxide during concrete production have pushed the scientific community to develop innovative ways towards reductions of such carbon dioxide emissions. An effective way is to use waste materials to replace conventional concrete materials, but this may come at the cost of reduced concrete performance. Hence, there is a need to link the carbon dioxide emission of concrete with concrete strength (strength-carbon dioxide emission relationship). This study bridges this gap by investigating the possibility of reducing carbon dioxide emissions in concrete by incorporating waste brick powder (WBP) and waste tire rubber (WTR) using a strength-based approach. This resulted in the formulation of three concrete grades of 20 MPa, 25 MPa and 30 MPa. It is shown that the impacts of including WBP and WTR on carbon dioxide emissions of concrete mixes are significant. Moreover, the compressive strength values corresponding to contents of 5 % WBP and 20 % WTR reduce dramatically by more than 32.57 % in comparison with conventional concrete mixes. However, 5P0T and 5P10T concrete mixes reveal both the reductions in carbon dioxide emissions and reasonable concrete strength. The present research therefore shows that certain concrete mixes incorporating WBP and WTR can provide the driving force for reducing carbon dioxide emissions and preventing substantial compressive strength reductions.

Investigate the mechanical behavior of alkali-activated slag mortar using sustainable waste sodium silicate-bonded sand as an alkali activator and carbon free aggregate

Various products generate different types of industrial by-products based on their production characteristics and procedures. Therefore, an accurate classification of these characteristics would contribute significantly to achieving the goals of resource recycling and environmental protection. This study focused on Waste Alkali-Activated Slag Mortar (W-AASM). In the past, inorganic aggregation technology was successfully adopted to replace conventional concrete binding materials and reduce cement usage. Besides utilizing inorganic aggregation technology, the study has introduced a novel industrial by-product known as Waste Sodium Silicate-Bonded Sand (WSSS). WSSS not only serves as a substitute for sodium silicate in alkali-activated agents but also acts as a complete replacement for fine aggregates in mortar. The experimental findings showed that, in addition to fulfilling the original strength requirements of concrete, it results in a significant reduction in cement consumption, minimizing the extraction of natural resources, and decreasing the overall cost of Alkali-activated concrete production. The study highlighted the advantage of WSSS and showed a new dimension of waste foundry sand application in the concrete industry. This method leads to the recycling of waste materials and their optimal use, and as a result, leads to a sustainable ecosystem. The results of this study can be applied to secondary structures in civil engineering and construction projects in the future, such as precast concrete products, concrete pavements, or roads.

Cost Effectiveness and SWOT Analysis of Using Conventional or Light-Weight Concrete Materials in Buildings Rested on Weak Soils

Cost Effectiveness and SWOT Analysis of Using Conventional or Light-Weight Concrete Materials in Buildings Rested on Weak Soils

Bond behavior of magnesium potassium phosphate cement (MKPC) coating for steel reinforcement in conventional concrete and related repair materials

Bond behavior of magnesium potassium phosphate cement (MKPC) coating for steel reinforcement in conventional concrete and related repair materials

Experimental and Statistical Study of Flexural Strength in Ternary Blended High-Performance Concrete using Alcofine

The primary aim of this research is to conduct a comprehensive comparative experimental and statistical study on the flexural strength of a novel ternary blended high-performance M30 grade concrete incorporating 20% Alcofine in comparison to traditional concrete.The components employed in the experimental investigation of high-performance M30 concrete incorporating Alcofine, in contrast to conventional concrete, comprise cement, fine aggregate, coarse aggregate, water, Alcofine, and additional cementitious materials like fly ash and silica fume. The Flexural Strength of high-performance M30 concrete containing Alcofine significantly influences the performance of concrete structures, rendering it a critical mechanical property for examination in the comparative analysis. The mean flexural strength of the Conventional Concrete group measured 8.1111 N/mm^2, with a standard deviation of 0.75840 and a standard error of the mean of 0.17876. In contrast, the Ternary Blended Concrete group exhibited a higher mean flexural strength of 12.5000 N/mm^2, coupled with a larger standard deviation of 2.09341 and a standard error of the mean of 0.49342. The statistical power analysis, involving parameters such as alpha (α) and beta (β), with commonly used values of 0.05 or 0.01, indicates a significance level of 5% or 1%, respectively. Further research could delve into refining the optimal percentage of Alcofine and exploring its long-term performance under varying environmental conditions. Keywords: Ternary Blended Concrete; Alcofine; Flexural Strength; Comparative Analysis; Statistical Study

Effects of Roller Compacted Concrete Incorporating Coal Bottom Ash as a Fine Aggregate Replacement

Coal bottom ash (CBA) is a by-product generated in the coal furnaces of thermal power plants. It has adverse effects on the environment and requires additional landfill storage. However, the physical appearance of CBA is similar to that of sand, with particle sizes ranging from fine to coarse aggregates. Hence, many previous studies have focused on its application instead of sand for conventional concrete and structural fill materials considering natural sand depletion. Roller compacted concrete (RCC) is a zero-slump concrete with better compressive strength than conventional concrete because of the aggregate interlock achieved due to the compactness. It uses a low cement content but requires a large amount of sand. However, the applicability of CBA to RCC is limited. The properties of CBA may vary depending on the location. Therefore, this study aims to evaluate the effect of CBA as a sand replacement in RCC in terms of strength and long-term performance by conducting an empirical experiment under given conditions. Initially, a comprehensive literature review of various concrete strengths using CBA as sand replacement is provided. Thereafter, details related to the experiments on the strength and durability of the given CBA are presented. The results show that the RCC strength improves when CBA increases owing to the good gradation and low percentage of calcium oxide. Furthermore, the samples displayed acceptable freeze–thaw resistance values, but the scaling resistance values were small, owing to the high-water absorption. Therefore, CBA can be used in RCC as sand for improved structural performance, while additional research should be conducted to improve its long-term performance.

Dimensional precision and wear of a new approach for prototype tooling in deep drawing

In this work, we present and evaluate a new approach for prototype tooling in deep drawing based on direct polymer additive tooling. With fused filament fabrication (FFF) a PLA shell is printed additively. Afterwards, this is filled with ultra-high performance concrete (UHPC). UHPC is characterized by its higher strength properties compared to conventional concrete materials, which makes the material feasible for forming applications. Two configurations of these hybrid UHPC polymer additive are possible: either the PLA shell is in contact with the sheet metal during forming or UHPC. The hybrid UHPC polymer additive tooling approach has the potential to be more cost-efficient for small series. The dimensional precision and wear of such hybrid tools is evaluated using a standard cup geometry. A test series of 30 cups with sheet metal DX56+Z with 1 mm thickness was drawn with the hybrid tools as well as with a polymeric tool and a conventional steel tool. The dimensional precision and wear of the prototype tools was evaluated optically.

Structural performance of Nano alumina-based RC element with polypropylene fibre and GGBS: An experimental assessment

In today's scenario, the essential ingredients of concrete, such as cement, and fine and coarse aggregate will vanish completely in a few decades due to its overexploitation and unscaled utilization. Similarly, cement has contributed to more emissions of carbon dioxide into the atmosphere during its stage of manufacturing, and it’s become a major influencer of increasing global temperatures. Recent researchers are finding alternative sources of materials that replace fully or partially the role of conventional concrete materials. Several industrial and agricultural solid residues are under investigation to be utilised nowadays to alter the place of conventional concrete materials and to control the impact of environmental problems. In this study, the performance of structural RC elements of M35 grade was evaluated by replacing the Nano alumina in a fixed proportion of 1% with the inclusion of ground granulated blast furnace slag and Polypropylene fibre at definite proportions in place of cement as per mix design. Engineering parameters such as compression, modulus of rupture and elasticity, crack width, and rate of deflection was examined. Based on the results of experiments, it was found that the cement proportion CAG1 and CAGP4 have provided the promotable result when compared to conventional concrete and led to using these materials instead of cement has made RC elements stronger than when they were made with regular cement.

Seismic collapse assessment of archetype frames with ductile concrete beam hinges

Highly ductile cement-based materials have emerged as alternatives to conventional concrete materials to improve the seismic resistance of reinforced concrete (RC) structures. While experimental and numerical research on the behavior of individual components has provided significant knowledge on element-level response, relatively little is known about how ductile cement-based materials influence system-level behavior in seismic applications. This study uses recently developed lumped-plasticity models to simulate the unique failure characteristics and ductility of reinforced ductile-cement-based materials in beam hinges and applies them in the assessment of archetype frame structures. Numerous story heights (four, eight, and twelve), frame configurations (perimeter vs. space), materials (conventional vs. ductile concrete), and replacement mechanisms within the beam hinges are considered in the seismic analysis of the archetype structures. Results and comparisons are made in terms of the probability of collapse at 2% in 50-year ground motion, mean annual frequency of collapse, and adjusted collapse margin ratio (ACMR) across archetype structures. The results show that engineered HPFRCCs in beam plastic-hinge regions can improve the seismic safety of moment frame buildings with higher collapse margin ratios, lower probability of collapse, and the ability to withstand large deformations. Data is also reported on how ductile concrete materials can reduce concrete volume and longitudinal reinforcement tonnage across frame configurations and story heights while maintaining or improving seismic resistance of the structural system. Results demonstrate future research needs to assess life-cycle costs, predict column hinge behavior, and develop code-based design methods for structural systems using highly ductile concrete materials.

Experimental assessment and constitutive modelling of rubberised One-Part Alkali-Activated concrete

This study deals with the development and assessment of rubberised one-part alkali-activated concrete. An experimental programme, focusing on optimising the material proportions for high flowability and compressive strength, is firstly described. This includes varying the proportions of aluminosilicate precursors, binder-to-aggregate ratio, activator dosage, and admixture quantity to find an optimum mix design with stable strength development up to 90 days. Crumb rubber particles are then added to replace up to 60 % by volume of the natural mineral aggregates. The effect of rubber addition on the mechanical properties is quantified and analytical expressions for the compressive strength, elastic modulus, splitting tensile strength, and flexural strength are presented. A database consisting of 241 conventional rubberised concrete as well as 57 rubberised alkali-activated mixes, available in the literature, is then assembled and used for direct comparison of the characteristics of different rubberised concrete materials. It is shown that the degradation in compressive strength for one-part rubberised alkali-activated concrete with high rubber replacement ratios falls within similar ranges as conventional and two-part alkali-activated rubberised concrete. However, the results show that the elastic modulus of one-part rubberised alkali-activated concrete is significantly lower than that of rubberised concrete mixes with the same compressive strength. Moreover, while the lateral crushing strain of one-part rubberised alkali-activated concrete increases with higher rubber replacement ratios, the axial crushing strain reduces slightly. It is also shown that the post-peak stress–strain response exhibits greater softening with higher rubber ratios. Based on the findings of the study, constitutive models for representing the compressive stress–strain response and flexural stress-crack width response are proposed. The presented expressions provide insights into the fundamental mechanical properties of rubberised one-part alkali-activated concrete, hence paving the way for their potential use in structural members, particularly those requiring higher ductility, while also offering a sustainable alternative to conventional concrete materials.

Bendable concrete in construction: Material selection case studies

• A dataset of ECCs is created and manually installed in Ansys Granta Selector. • ECC fills empty space on the material property charts (Ashby charts). • Material selection examples dealing with a bridge deck link slab are employed. • ECC outperforms conventional concrete materials in all case scenarios considered. Engineered cementitious composites (ECCs) have been developed to solve one of the most fundamental drawbacks in the most produced materials for our built environment. Namely, the brittle nature of concrete. ECC or ‘bendable’ concrete has evolved from the endeavors of a single research group to a material family in its own right, studied in hundreds of research laboratories and actively deployed in structures around the world. ECCs are a class of cementitious materials with unique tensile properties that are distinct from normal cement-based materials. This sort of material innovation is exactly what is anticipated when material property charts (Ashby charts) display empty areas in the material-property space. This paper demonstrates the uniqueness and advantages of these materials with a set of material selection case studies dealing with a bridge deck link slab. The material selection is carried out using Ansys Granta Selector, with ECCs added as new records into the existing database. The case studies show how ECCs outperform conventional concrete materials and highlight the potential of ECCs in construction.

Investigation study of enhance the strength by using hybrid nano-composites on conventional cement concrete

Generally, incorporation of nano-particles with conventional concrete (CC) materials expands the bulk belongings of concrete by renovating molecular structures and permits the cement-based materials converted high-strength and durable products. The concentrated tensile possessions of the concrete confines its submissions where the flexural and tensile possessions of the concrete are major. In this steel and synthetic-fibres are expressively enhanced the tensile, toughness, impact resistance and energy-absorption capacity (EAC) of the concrete. Even yet the presence of fibre enhanced the tensile strength capacity (TSC) of the concrete, it hasn’t better the compressive strength capacity (CSC) of concrete suggestively. Therefore, it is very overbearing in growth of compressive strength of the concrete where the compressive tensile belongings to the concrete are major for its application. Investigation was carried to study the impact of nano-Al2O3, nano-Fe2O3, and their hybrid combinations on the setting time, microstructure, fresh, and strength properties of conventional cement concrete. Binding material of concrete mixtures was replaced by different nanoparticles, namely nano-Fe2O3 and nano-Al2O3, with four replacement rates (up to 4 %) that makes somewhat of change in building materials and gives energy to the building. The slump cone test was performed to assess the workability of concrete mixtures. Strength characteristics were evaluated, including the compressive, split tensile, and flexural strengths, for mixtures hardened after 7, 28, and 90 days. Moreover, the slump value of the mixture was decreased with an increase in the replacement rate of nanoparticles. However, slump values were within the acceptable workability and did not affect concrete compaction. However, the strength enhancement of the hybrid nano mixtures was relatively equal to that of the mixtures with only nano-Fe2O3 or nano-Al2O3. The test results revealed that nanoparticles can enhance the strength and microstructure properties of concrete.

Understanding the mining waste as resources in self-compacting concrete: A numerical study on sustainable construction

To achieve effective resources conservation mechanism and efficient waste management system, recent studies more focused on converting the waste into useful resources in different applications. Construction sector is one of the key sector for development and consumes high quantity of resources, hence, to tackle the high consumption, studies started to introduce waste materials (for ex: fly ash) as replacement of conventional building materials. Such waste material inclusion becomes very popular in concrete applications. However, some of the waste material do have the potential to be a better replacement of conventional concrete materials, which are limited in the existing studies, especially mining waste. This study focused on this gap, by introducing mining waste as potential replacement material in concrete applications, in specific to self-compacting concrete. This step will move forward the existing construction sector towards sustainability by adopting sustainable construction concepts. Despite of these significances, there are very smaller number of studies are reported with the application of mining waste in self compacting concrete. This study focused on this issue by analyzing the existing challenges involved in the inclusion of mining waste in self compacting concrete applications. A numerical modelling has been included in the study to understand and analyze the interrelationship and interdependencies among the collected challenges. With the results of the study, the challenges for sustainable construction through the inclusion of mining waste in self compacting concrete can be eliminated.

Combined Effect of Ternary Blended Cementitious Materials in Self-compacting Concrete

Self Compacting Concrete (SCC) is a type of special concrete which possess self packing and flowability to fill the formwork space completely by its own weight without any external vibration or compaction. Research studies on finding efficient, economical and eco-friendly materials to replace the conventional concrete materials are increasing day-by-day. An important constituent material of concrete is cement which contributes to the environmental hazardous problem of CO2 emission. In this view, the present study investigated the fresh and hardened properties of SCC in which cement is partially replaced by multi-cementitious materials namely fly ash, alccofine and Recycled Concrete Powder (RCP). Fly ash and alccofine are evident materials to replace cement in concrete. In addition to the substitution of cement by 20% replacement by fly ash and 10% replacement by alccofine, recycled concrete powder collected from construction wastes are also incorporated (5%, 10%, 15%, 20%) and investigated. Water/binder ratio is kept constant as 0.45. Polycarboxylate based super plasticizer (Conplast SP430) was used. The experimental program comprises testing the fresh stability by determination of flowability, passing ability and viscosity, mechanical strength testing including compressive strength, split-tensile strength and flexural strength and durability properties such as water absorption, sorptivity and acid-attack of SCC specimens. The test results showed that 10% recycled concrete powder exhibited better performance in fresh stability and satisfied performance mechanical strength. Increase in RCP content beyond a limited proportion possesses detrimental effects on the durability characteristics.

Effects of Using Green Concrete Materials on the CO2 Emissions of the Residential Building Sector in Egypt

Increasing the rate of construction material consumption has caused significant environmental problems in recent decades, especially the production of ordinary Portland cement (OPC), which has been associated with 8% of the world’s human CO2 emissions and is considered the leading binder of concrete. This study aims to investigate the effects of substituting conventional concrete (CC) material with green concrete (GC) in the non-structural concrete works of a residential building in New Borg El-Arab City, Egypt. It attempts to establish what the effects are of using GC on cement, natural aggregates, and CO2 emissions in the design phase. By using a design-based solution (DBS), we began with redesign, reduce, reselect, reuse, and recycle strategies to find an optimal solution for applying recycle aggregate concrete (RAC) as a replacement material in selected building parts, such as the internal floor, external sidewalk, entrance steps, and wall boundary. AutoCAD software and 3Dmax were used to modify the original design and obtain two design references with four different scenarios. Comparative analyses were applied to investigate the effects of different concrete materials. The results show a reduction of about 19.4% in cement consumption in terms of the total concrete of the building and a 44.5% reduction in CO2 emissions due to the reduction of cement in specific building parts. In addition, this solution decreased natural coarse aggregate (NCA) consumption by 23.7% in the final concrete. This study recommends that GC materials close the loop of cementitious material consumption to reduce environmental impacts and achieve sustainability in the Egyptian building sector.

Effect of Waste Fines and Fibers on the Strength and Durability Performance of Silica Fume Based Reactive Powder Concrete

The demand and consumption of conventional concrete materials is increasing day by day, which in turn leads to the extinction of natural resources. Certain researchers tend to draw a circle to solve this global problem by finding alternative materials satisfying all aspects, mainly efficiency, eco-friendly and economical. The present research work aimed to study the combined use of coal bottom ash (CBA) and waste concrete powder (WCP) in silica fume based reactive powder concrete (SF-RPC) subjected to thermal curing. The replacement of cement by silica fume was limited to 20% and the fine aggregate quartz sand replaced by CBA and WCP varied from 5% to 25% each. The material composition of SF-RPC involves the exclusion of coarse aggregates and the inclusion of finer materials with micro-steel fibers. The steel fibers played a significant role in order to obtain a ductile and stable product of SF-RPC. The experimental investigation on SF-RPC comprised of the determination of fresh concrete properties such as slump flow and the compaction factor, as well as mechanical properties like compressive strength, flexural strength and split-tensile strength. The study was also extended to investigate durability properties such as water absorption, sorptivity and resistance to acid attack. The results showed that silica fume proves to be a feasible alternative to partially replace cement and also that optimum incorporation of pre-treated and processed CBA and WCP attains better mechanical and durability performance without compromising the necessary qualities.

Investigation of the Mechanical, Microstructure and 3D Fractal Analysis of Nanocalcite-Modified Environmentally Friendly and Sustainable Cementitious Composites

Unlike conventional concrete materials, Engineered Cementitious Composites (ECC) use a micromechanics-based design theory in the material design process. Recently, the use of nanoparticles in various concretes and mortars has increased. This study used nanocalcite to investigate the mechanical, microstructural fractal analysis of environmentally friendly nanocalcite-doped ECC (NCa-ECC). This paper investigated the effects of nanocalcite (NCa) with different contents (0.5, 1, and 1.5% by mass of binder) on the mechanical properties of engineered cementitious composites (ECC). For this purpose, compressive strength, ultrasonic pulse velocity (UPV), and flexural strength tests were conducted to investigate the mechanical properties of the ECC series. In addition, SEM analyses were carried out to investigate the microstructural properties of the ECC series. The content of nanocalcite improved the mechanical and microstructural properties of the nanocalcite-modified ECC series. In addition, the 1 NCa series (1% nanocalcite modified to the mass of the binder) had the best performance among the series used in this study.

Experimental study of low carbon emission alternative concrete

Urbanization and mass construction of housing will increase the consumption of cement and available natural resources such as sand and water. The production of cement generated from various industries leads to the emission of carbon dioxide gas in huge quantities into the atmosphere and creates serious problems in handling and disposal. So, the replacement of conventional materials with alternative materials for the preparation of concrete is needed. If the alternative cementitious and industrial waste materials are found suitable in replacing the ingredients of concrete then it can reduce the cost of construction. The present paper represents an experimental study of low carbon emission alternative concrete by replacing conventional concrete materials with alternative materials like geopolymer as binding material, copper and ferrous slag as fine aggregates, steel slag as coarse aggregates, and alkaline solution as an activator. Study made to examine the properties of low carbon emission alternative concrete proposed. The fresh and hardened state characteristics of low carbon emission alternative concrete are evaluated for both oven and ambient curing conditions. It is noticed that the time taken to achieve the strength by oven curing is less than ambient curing but had no major difference in load-carrying capacity and the results obtained are in good concurrence with conventional concrete.