Concrete Construction Industry Research Articles

Influence of Steel Slag as a Partial Replacement of Aggregate on Performance of Reinforced Concrete Beam

Amidst the global pursuit of sustainable alternatives in concrete production, this study explores the viability of incorporating by-products or waste materials as aggregates to support the concrete construction industry, with a specific emphasis on steel slag. The objective of this study is to evaluate the effectiveness of steel slag as a partial replacement for fine and coarse aggregates in concrete production. The experiment involved casting 30 cubes and 10 beams, replacing fine aggregate from 0 to 60%. Flexural and compressive strength tests at 7 and 28 days followed the ACI method. Results revealed that a 30% replacement of fine aggregate with steel slag led to higher compressive strength at both 7 and 28 days, while a 45% replacement showed superior flexural strength at 28 days. Further chemical analysis and optimization are recommended for deeper insights. The study concludes with marginal improvements in compressive and flexural strength with steel slag partial replacement, identifying 30% for fine aggregate and 45% for coarse aggregate as optimal replacements. In addition, the mineral composition of steel slag exhibits significant variability, with compounds, including silicon dioxide (SiO2), iron oxide (Fe2O3), manganese oxide (MnO), aluminum oxide (Al2O3), and calcium oxide (CaO). Chemical analysis indicates high silicate content and minimal alkali content, contributing to enhanced strength during concreting. Higher steel slag replacement reduces workability, confirmed by slump tests. However, all mixes maintain a true slump, and unit weight increases with steel slag aggregate replacement. Compressive strength improves incrementally with higher steel slag content, echoing prior research. In addition, flexural strength rises with steel slag replacing both coarse and fine aggregates, suggesting enhanced performance in reinforced concrete structures. These findings highlight steel slag’s potential as a sustainable alternative in concrete production, aiming to advance its application in the construction industry, promoting environmental sustainability and economic viability.

CARBON FOOTPRINT REDUCTION USING GEOPOLYMER CONCRETE

The size and complex nature of today's construction project resulted in a global increase of the carbon footprint. Increased carbon dioxide emissions results in a severe deterioration to the environment and negative health implications. Recent studies showed that the production of 1 metric ton of portland cement results in the evolution of 0.9 metric tons of carbon dioxide. At this rate, the construction industry represents a significant threat on mankind. This paper presents geopolymer (cement-free) concrete applications in the United States local construction market. Geopolymer concrete production depends on the activation of a pozzolanic supplementary cementitious material (SCM) with a high aluminosilicate content using alkaline solution as sodium hydroxide (NaOH). The SCM activated material-known as precursor-forms a three-dimensional polymer that binds the aggregates instead of hydrated portland cement. The widespread of geopolymer concrete will significantly reduce the need to portland cement; hence, reduces the carbon emissions resulting from cement production. In addition to the environmental advantages, geopolymer concrete is highly durable due to the fine size of SCMs particles. Geopolymer concrete is more resistant to alkali-silica reactivity, and early age cracking. The widespread of geopolymer concrete in construction industry, especially in infrastructure projects, will result in significant improvement in projects condition, and lower the need to frequent maintenance, repair, and replacement of projects.

CARBON FOOTPRINT REDUCTION USING GEOPOLYMER CONCRETE

The size and complex nature of today's construction project resulted in a global increase of the carbon footprint. Increased carbon dioxide emissions results in a severe deterioration to the environment and negative health implications. Recent studies showed that the production of 1 metric ton of portland cement results in the evolution of 0.9 metric tons of carbon dioxide. At this rate, the construction industry represents a significant threat on mankind. This paper presents geopolymer (cement-free) concrete applications in the United States local construction market. Geopolymer concrete production depends on the activation of a pozzolanic supplementary cementitious material (SCM) with a high aluminosilicate content using alkaline solution as sodium hydroxide (NaOH). The SCM activated material-known as precursor-forms a three-dimensional polymer that binds the aggregates instead of hydrated portland cement. The widespread of geopolymer concrete will significantly reduce the need to portland cement; hence, reduces the carbon emissions resulting from cement production. In addition to the environmental advantages, geopolymer concrete is highly durable due to the fine size of SCMs particles. Geopolymer concrete is more resistant to alkali-silica reactivity, and early age cracking. The widespread of geopolymer concrete in construction industry, especially in infrastructure projects, will result in significant improvement in projects condition, and lower the need to frequent maintenance, repair, and replacement of projects.

Use of recycled mortar as fine aggregates in pavement concrete applications

The use of recycled aggregates derived from construction and demolition wastes increased in the concrete construction industry. While the coarse fraction (i.e., from 5 to 20 mm) was successfully recycled, the fine fraction (i.e., from 0 to 5 mm) is hardly recyclable given its heterogenous nature and poor physical properties. This paper assesses the feasibility of recycled mortar aggregate (RMA) in pavement concrete applications requiring superior resistance to weathering and wearing effects. Three concrete strength grade categories prepared with different water-to-binder ratios (w/b) of 0.4, 0.5, and 0.6 are investigated; the natural sand replacement levels by RMA varied from 0 % to 60 % by volume, at 20 % increment rates. Test results showed that the detrimental RMA effect on durability depends on the concrete strength category, requiring proper adjustment of the maximum replacement rate to maintain acceptable losses in performance. Hence, the higher strength grade mixtures prepared with 0.4 w/b were found to yield significant drops in durability reaching 25 % in water sorptivity, 18 % in abrasion, and 22 % due to freeze/thaw (F/T) cycles. In contrast, the lower strength grade concrete made with 0.6 w/b exhibited marginal degradation in strength and durability, despite the incorporation of 60 % RMA. The resulting losses in sorptivity, abrasion, and F/T cycles were limited to 13 %, 8 %, and 12 %, respectively.

Развитие строительства и промышленности строительных материалов в Магаданской области в 1953–1964 гг.

The article is devoted to a comprehensive analysis of the development of the construction industry and construction materials industry in the Magadan Region in 1953–1964. The key areas and results of construction activities, the dynamics of capital investments in construction in various sectors of the economy, the establishment and development of enterprises for the production of wall materials, precast concrete and other construction industry in the region are examined. Particular attention is paid to the analysis of the problems of logistical support for construction, the cost of building materials, and the shortage of certain types of products. The pace and volume of housing and social and cultural construction are considered. Based on a wide range of archival sources, it is concluded that the development of construction and local production of building materials was of great importance for the formation of the Magadan Region as a northern region of the country during the period under review.

An Experimental Investigation of a High-Density Concrete with Waste Ceramic Tiles Used as an Aggregate

Abstract: The use of waste material as aggregates in civil engineering applications is beneficial and increasingly desirable because it reduces the environmental impact and economic cost of mining, processing, and transportation operations. Therefore, this study focused on establishing the effect of crushed tile on the compressive strength of concrete. In this research investigation, ceramic waste tile waste was substituted for natural coarse aggregate in concrete to varying degrees from (0, 10, 20, and 30%), and the M-20 graded concrete was used to produce high density concrete. After 3, 7, and 28 days of the curing process, few number of new concrete mould were casted and evaluated about the Compressive Strength and Split Tensile Strength. The findings of these results showed that 35% replacement of naturally made coarse aggregate with the ceramic tile aggregate which contributes the higher compressive strength to produce the high-density concrete in construction industry.

Effect of Coarse Aggregate Size Variation on Compressive Strength of Concrete along the Length of Kali Gandaki River

The Kali Gandaki River is renowned for its diverse geological composition, providing a unique opportunity to examine how the inherent characteristics of coarse aggregates impact concrete performance in terms of compressive strength. This research delved into the influence of varying coarse aggregate sizes on the compressive strength of concrete obtained from different points along the Kali Gandaki River. Multiple samples of coarse aggregates were gathered from distinct geological regions along the river. The study adopted a concrete mix design for M20, and concrete cubes were manufactured with coarse aggregate sizes ranging from 10mm-16mm, 16mm-20mm, 20mm-25mm, to 25mm-31.5mm. All sample sets underwent compressive strength testing after 7 and 28 days of curing. The results revealed that, under identical curing conditions and water-cement ratios, the compressive strength of the produced concrete increased with the aggregate size, reaching a peak at 25mm. Additionally, among the surveyed locations, namely Ramdi Ghat, Khada Ghat, Pakhichaur Hungi Ghat, and Belchaur Ghat, Belchaur Ghat exhibited superior performance in compressive strength. The findings of this work aim to contribute valuable insights to the field of concrete technology and construction industry.

Evaluating GFRP bars under axial compression and quantifying load-damage correlation

Fiber-Reinforced Polymer (FRP) bars have become widespread in the concrete construction industry because of their superior mechanical, physical, and durability properties. Although the tensile performance of FRP bars has been well studied, only a limited number of research projects have evaluated the compressive behavior of FRP bars due, among other reasons, to the need for a standard test method. This research aims to develop a test method to apply compression at the center of the FRP bar to avoid load eccentricity effects using a steel centering fixture with a plastic 3D-printed plug. To evaluate the ultimate compressive strength and elastic modulus, two different Glass FRP (GFRP) bars, with a 12.7 mm nominal diameter, but with two different length-to-diameter ratios of 2 and 4, were considered. The effect of 3D-printed plugs and cutting surface quality was also evaluated. The main contribution of this research is providing a straightforward test set-up for obtaining the compressive behavior of GFRP bars. The results showed that the compressive strength and elastic modulus of the tested GFRP bars are considerable in a way that the elastic modulus of the G1 bars in compression was equal to the tensile elastic modulus, so neglecting the effects of these bars in designing compressive members is too conservative.

Examining the endpoint impacts, challenges, and opportunities of fly ash utilization for sustainable concrete construction

Fly ash has been widely used as a cement substitute to improve the sustainability of concrete. Although the advantages of fly ash have been extensively documented, there is a gap in understanding why its use in mass concrete applications remains low in some countries, such as the Philippines. Thus, this work aims to understand the issues that impede waste utilization, particularly fly ash in the concrete construction industry, quantify the impact of the current practice, and identify opportunities for sustainable fly ash utilization. Endpoint impact analysis was conducted through the life cycle using SimaPro 9.3 to quantify the impacts on human health, ecosystem, and resources of 31 concrete mixtures of low, normal, and high strength design with 0 to 20% fly ash as cement replacement. In-depth, semi-structured interviews with key stakeholders were undertaken to determine the institutional, economic, social, and technological challenges related to the utilization of waste materials in large-scale concrete construction. More than 90% of the total impact of concrete contributes to damage to human health, primarily caused by global warming and fine particulate matter. The use of fly ash at 20% replacement by weight of cement benefits resources more significantly than human health and the ecosystem. The use of chemical admixture to improve strength has a significant impact on resources. High fly ash replacement for normal and high-strength concrete has a greater reduction in all endpoint categories than for low-strength design. Recommendations are proposed to maximize the beneficial impact of using fly ash in the concrete industry.

3D Printed Houses

The construction industry is expected to go through large transformations since construction automation is anticipated to drastically alter standard processing technologies and could lead to possible disrupting technologies such as 3D concrete printing (3DCP). While 3D printing techniques have been successfully applied in a wide range of industries such as aerospace and automotive, its application in concrete construction industry is still in its infancy. 3DCP can allow freeform construction without the use of expensive formwork, which in return offers excellent advantages compared to conventional approach of casting concrete into a formwork. In the last few years, different 3DCP technologies have been developed. This paper presents the current progress of 3DCP technologies

Modeling and experimental studies on energy consumption and properties of concrete containing waste brick powder and waste tire rubber for sustainable construction

The advantages of utilising waste materials in concrete have led to the use of waste brick powder (WBP) and waste tire rubber (WTR) in concrete production. The awareness of factors influencing energy required during concrete production and the capability to optimise energy consumption and modified concrete properties could pave way for adoption of modified concrete in construction industry. This paper is aimed at generating models via response surface methodology (RSM) which are suitable at establishing best compromises amongst responses of energy consumption, unit weight and compressive strength of concrete. The generated models facilitated the understanding of effect of parameters of WTR (0–20%) substituting coarse aggregates and WBP (0–5%) substituting cement on energy consumption, unit weight and compressive strength responses. The reliability of the constructed models was verified using analysis of variance (ANOVA). The models using RSM illustrated increased R2 values of larger than 0.84 for all responses which proved that the established models were reliable in the prediction of all the responses. The energy consumption response was established with the linear regression model while the unit weight and compressive strength responses were established with quadratic regression models. The desirability analysis produced 5% WBP and 0.614% WTR as values illustrating higher concrete unit weight at decreased energy consumption for concrete production. Optimisation procedure of energy consumption and compressive strength of concrete by desirability analysis provided 5% WBP and 0% WTR as optimum parameters establishing higher compressive strength at lower energy consumption. Moreover, no significant relationship was noticed between energy consumption of concrete and 28-days compressive strength of concrete as the compressive strength increased. The findings in this research motivate the reduction of energy consumption during concrete production without significantly influencing concrete properties.

Overview of meshfree modeling of the flowability of fresh self-compacting concrete for sustainable structures

The flow of Bingham non-Newtonian incompressible fluids like concrete is associated with the large deformation of materials. The modeling and simulation of these fluids’ flow behavior by using conventional numerical methods. suffer problem-formulation setbacks due to mesh distortion. In order to compensate for the mathematical inefficiencies encountered in the process, particle-based methods have evolved and been applied. Also, the use of some particle-based methods produces a stretch of unreliability due to the Eulerian algorithmic trail, which visits every particle edge allowing for revisiting vertices during its operation. This makes the model path cumbersome and time-consuming. Concrete flow is an important element of sustainable infrastructural development, and its understanding strengthens the efficiency of concrete handling and placement during construction activities. In this paper, a mesh-free method of modeling the flowability of self-compacting concrete (SCC) known as the smoothed particle hydrodynamics (SPH) has been reviewed. It derives its advantage from the Lagrangian algorithmic trail. This explores its merits and demerits in the concrete construction industry to propose the best practices for the passing ability, filling ability, and dynamic stability of the flowing fresh concrete (FFC)

Steel Wire Wrapped Bamboo – As a Sustainable Reinforcement in Alkali Activated Fly Ash-Slag based Concrete

The cost ratio of steel to concrete exceeding 100 in most of the RCC structures, alternative materials for replacing steel are underway to develop a sustainable built environment. Bamboo has been in housing industry since time memorial as a standalone structural member for lighter loads of roofing and wall cladding units. It has been tested for its use as reinforcement in OPC based cement concrete structures replacing steel reinforcement with appreciable performance while requiring serious attention on serviceability and durational aspects. The alkali activated low calcium fly ash & slag-based concrete with steel reinforcement as structural components cured at ambient temperature (RGPC) are being popularized in the most consumed sector of concrete construction industry.

Factors Affecting Construction Productivity for Steel Rebar Work in Hot Climate Country

Introduction: Construction industry is increasingly emphasizing productivity due to its effect on key performance indicators such as schedule, budget, and quality of work. This study aims to identify and rank the factors affecting the productivity of steel rebar work in construction projects in a hot climate. Among the activities involved in structural reinforced concrete work, fabricating and placing reinforced steel on a construction site is considered the most labor-intensive, outdoor, and time-consuming. Methods: In this paper, an intensive qualitative literature review is conducted to identify the factors affecting the productivity of steel rebar work in concrete construction. Initially, forty factors were identified from the literature affecting the productivity of steel rebar work in Saudi Arabia. Final list of thirty-seven factors was used in the questionnaire survey. The identical nature and core content of these factors are clustered and grouped into five categories: technical, labor, management, external, and financial. As part of this study, fifty contractors working in the Saudi Arabian construction industry are recruited to participate and complete a structured pilot study questionnaire. Results: The results of the questionnaire are weighted using the pairwise comparison method and then ranked based on the Analytic Hierarchy Process technique. The analysis of the thirty-seven factors results in a top ten list of the leading factors that directly impact the productivity of steel rebar work in concrete construction projects in Saudi Arabia. These factors are (1) humidity, (2) delay of salary, (3) sandstorms, (4) payment delay by client, (5) labor's low wage, (6) lack of financial incentives, (7) labor work experience and skills, (8) completeness of drawings, (9) poor labor relations, and (10) labor absenteeism. The general trend in these studies is that the factors tend to vary from jurisdiction to jurisdiction, from one construction project to another, and are directly related to the zone or country of construction. Conclusion: These findings benefit stakeholders working in the concrete construction industry in Saudi Arabia, particularly project managers, project planners, cost estimators, and civil design and site engineers working on construction projects.

3D printed concrete as stay‐in‐place formwork: Mechanics during casting and curing

AbstractResearch in 3D concrete printing has gained an exponential increase in attention over the last decades. The automated production process can be beneficial to reduce material use and increase form freedom of produced elements. Disadvantages are the difficulty to apply reinforcement, the speed of execution if massive elements have to be made and the uncertain durability performance of the printed material. These aspects still lead to reticence in the concrete construction industry to use 3D printing at a large scale. To lower the threshold to move from the conventional toward the new construction technique, a combination of 3D printed and conventional concrete is proposed namely concrete elements with stay‐in‐place 3D printed formwork. In this paper, experimental research has been performed to investigate the behavior of 3D printed formwork during casting and curing of fresh material. Cylindrical formwork was printed on small scale and filled with self‐compacting concrete. During the experiments, strain development and temperature evolution were measured in and around the elements. The obtained data was analyzed taking in attention the material characteristics of both materials in order to separate the different mechanisms. Results showed that the formwork is subjected to the lateral pressure of the cast concrete, moisture warping and thermal curling. The strains in the formwork increase significantly after casting as a result of moisture warping and thermal curling. The peak strain of the concrete element is reached during the hydration phase of the cast concrete. As the cast concrete stiffened in a slightly deformed formwork, residual strains will be present after the element cooled down.

Constructivist multi-criteria model to support the management of occupational accident risks in civil construction industry

Civil construction is one of the industrial sectors with continuous growth globally, particularly in Brazil in the last 50 years. Unfortunately, it is also one of the productive segments with the highest incidence of accidents, which overshadows its merits as a driver of economic growth and job creation. The damage to workers’ health caused by accidents at work results from the presence of work environment risk factors. Therefore, this study aims to manage these risk factors for the civil construction industry. The work is original with respect to building a model to support risk management in civil construction for a specific and relevant context. It is ensured by presenting an unprecedented approach to the sector that incorporates information not considered by classic generic approaches. This research, thereby, seeks to build a model to support the risk management of accidents in the workplace in the prefabricated concrete construction industry. It is a case study with a constructivist approach and an exploratory and descriptive character, incorporating the Multicriteria Methodology for Decision Aiding-Constructivist (MCDA-C). The main findings include (i) identifying the strategic objectives: occupational safety policy, work environment, machines and equipment, condition of materials, procedures and methods, and skills, which were operationalized via 58 criteria; (ii) examining the scales of the criteria such as the performance profile of the current situation and the goal, highlighting the vulnerabilities and potentials; (iii) proposing improvement actions for the vulnerabilities, thus supporting risk management in the organization. Among the contributions, managers and professionals in the field contribute to the possibility of using an instrument customized to the context and legitimate to their concerns and values stands out. Furthermore, the contributions of researchers include the challenge of improving their generic models with the knowledge of personalized models.

Additive Manufacturing using mobile robots: Opportunities and challenges for building construction

In situ Additive Manufacturing (AM) has developed into an active research and industry-transfer area, mainly due to the increasing need for productive and sustainable methods in the concrete construction industry in combination with novel technological enablers. While current systems for in situ AM are often single large-scale stationary facilities, Mobile Additive Manufacturing (MAM) systems are an emerging technology that could provide scalability for AM processes on construction sites. This scalability is achievable through cooperability of multiple mobile robots on individual 3D printing tasks, while their mobility and autonomy enable deployment in both new and existing contexts, and coordination of operations for the direct and indirect interaction with humans. To ensure applicability and scalability, MAM closely integrates architectural, mechanical, and materials design, the manufacturing process, sensing, and control. With this paper, we give a comprehensive review of research trends, open questions and key performance indicators. We support the discussion with potential architectural application scenarios. Overall, we aim to indicate why addressing MAM is an inherently multidisciplinary challenge.

Early-Age Performance Analysis of Sludge Water Incorporation in High-Temperature Steam Cured Green High-Performance Concrete.

Sludge water (SW) with abundant sulfate ions (SO42−) was utilized in this work to replace freshwater (FW) to prepare green high performance concrete (GHPC). A comprehensive investigation was conducted to evaluate the early-age performance of GHPC specimen mixed with SW incorporation (GHPC-SW). High temperature steam curing (HTS) has been presented to prepare GHPC-SW specimens. The compressive strength of the GHPC-SW specimen cured by HTS curing for 2 days is 85.2 MPa, which is 34% higher than the compressive strength of the GHPC-SW specimen cured by 3 days standard curing as the reference. The mechanical property results reveal that the incorporation of SW makes no harmful effects on the strength formation of HPC specimens, compared with FW added specimens under the same curing methods. Moreover, XRD and TG analyses indicate that HTS curing can effectively improve the hydration degree of GHPC-SW specimens. MIP analysis has been conducted and the specimens cured by HTS curing exhibit a more refined pore structure with fewer harmful pores. This work lays a solid foundation for the utilization of SW in the concrete construction industry, which is resource saving and environmentally friendly.

Assessment of cracking performance in edge restrained RC walls

AbstractExcessive cracking due to restraint of thermal and shrinkage strains is a widespread problem in the concrete construction industry. In design, restraint induced cracking is managed by the provision of reinforcement intended to distribute internal strains in such a way as to control the cracking pattern and limit crack widths. The area of secondary (horizontal) reinforcement required in members such as retaining walls and water tanks is often governed by the need to control early age thermal cracking. This paper presents results from four edge restrained walls tested at Imperial College London and the University of Leeds as part of an Engineering and Physical Sciences Research Council funded project into restraint induced cracking. The paper describes the development of volumetric strain and cracking in the tested walls. The cracking performance is assessed by comparing the restrained strain with the tensile strain capacity of concrete.

The Past, Present and Future of Concrete Construction

Concrete has always been the major construction material since the historical past, at present and will continue into the future. This presentation covers the period from the first UK design code (CP 114, 1957) in UK to the current European design code (BS EN 1992-1-1: 2004) and their associated standards on concrete and its constituent materials. The 10th Professor Chin Fung Kee Memorial Lecture in 2000 on “Concrete: From 2000 psi to 80 MPa and Beyond” was delivered before the adoption of Eurocodes. This new system is based on performance approach, in place of the more prescriptive approach of the former UK system. Engineering education and practice have to meet the changes with updated knowledge to benefit from these advances in design, materials and construction. The main emphasis is on changes in concrete with new types of cement, addition, admixture and the diminishing stock of aggregates. Replacing the traditional reliance on past experience with innovative approaches in concrete technology based on acceptance of rational performance criteria leads to progress in the construction industry. The progressive advances over the past six decades provided by personal experience have transferred through the teaching, research and development of new concrete concepts in concrete technology to the construction industry. There is also an urgent need to look into the future direction for concrete and the associated challenges ahead with the expected global warming to achieve higher levels of strength, consistence and durability for a sustainable concrete construction industry.