Nondestructive test methods for concrete bridges: A review

NDT methods applicable to concrete bridges are reviewed. The methodology, advantages and disadvantages along with up to date research on NDT methods are presented. Different damage levels, having less dependence on inspector judgment, are suggested. Moreover, a flow chart based on damage level along with NDT methods and potential remedial measures are proposed for periodic health monitoring of structures

Nondestructive test methods for concrete bridges: A review

NDT methods applicable to concrete bridges are reviewed. The methodology, advantages and disadvantages along with up to date research on NDT methods are presented. Different damage levels, having less dependence on inspector judgment, are suggested. Moreover, a flow chart based on damage level along with NDT methods and potential remedial measures are proposed for periodic health monitoring of structures

A REVIEW OF MICROSCALE, RHEOLOGICAL, MECHANICAL, THERMOELECTRICAL AND PIEZORESISTIVE PROPERTIES OF GRAPHENE BASED CEMENT COMPOSITE

Extensive research on functionalized graphene, graphene oxide, and carbon nanotube based cement composites has been carried out to strengthen and overcome the shortcomings of construction materials. However, less literature is available on the pure graphene based cement composite. In this review paper, an in-depth study on a graphene-based cement composite was performed. Various structural forms of graphene and classifications of graphene-based nanomaterial have been presented. The dispersion mechanism and techniques, which are important for effective utilization in the construction industry, are reviewed critically. Micro-scale characterization of carbon-based cement composite using thermogravimetric analysis (TGA), infrared (IR) spectroscopic analysis, x-ray diffractometric (XRD) analysis, and morphological analysis has also been reviewed. As per the authors’ knowledge, for the first time, a review of flow, energy harvesting, thermoelectrical, and self-sensing properties of graphene and its derivatives as the bases of cement composite are presented. The self-sensing properties of the composite material are reported by exploring physical applications by reinforcing graphene nanoplatelets (GNPs) into concrete beams

Investigating BIM Implementation Barriers and Issues in Pakistan Using ISM Approach

The Pakistan construction industry recorded a high growth rate of 9.05% in 2016–2017. However, it fails to complete the projects within the specified cost, time and quality due to the use of traditional management techniques. This can be easily overcome by adopting and implementing new technologies like Building Information Modeling (BIM). In this study, a questionnaire survey was performed to find the present state of BIM in Pakistan and highlight the barriers in its successful adoption. In addition, Interpretive Structure Modeling (ISM) and Cross-Impact Matrix Multiplication Applied to Classification (MICMAC) analysis were used to identify interrelationships among these barriers. Out of 104 responses received, 63% of Architecture, Engineering and Construction (AEC) professionals were aware of BIM and among them, only 17% had utilized BIM in their projects, which is a very low percentage. The adoption of BIM in Pakistan is only at 11%. The respondents acknowledged that BIM helps in minimizing the cost and time of a project up to 57%. This study concluded that BIM is more economical and efficient than other management techniques. Moreover, this research also identifies the ISM and MICMAC analysis-based hierarchical model and three level strategy model that can facilitate the possible implementation. Solutions to common barriers around the globe are also proposed. Thus, by utilizing BIM, an economical, timely, properly managed project can be obtained in Pakistan and other developing construction markets all over the globe

A review of recent developments and advances in eco-friendly geopolymer concrete

The emission of CO2 and energy requirement in the production of Ordinary Portland Cement (OPC) causes the continuous depletion of the ozone layer and global warming. The introduction of geopolymer concrete (GPC) technology in the construction industry leads to sustainable development and cleaner environment by reducing the environmental pollution. In this article, constituents of GPC and their influence on properties of GPC has been reviewed critically. Fresh and hardened properties of GPC as well as the factors influencing these properties are discussed in detail. Flow charts have been proposed to show which factors have higher/lower impact on the fresh and hardened properties of GPC. A comprehensive review on the mix design of GPC, nanomaterial-based GPC, 3D printing using GPC, reinforced GPC and Global warming potential (GWP) assessment was conducted. Finally, the practical applications of GPC in the construction industry are provided

Life Cycle Impact Assessment of Recycled Aggregate Concrete, Geopolymer Concrete, and Recycled Aggregate-Based Geopolymer Concrete

This study presents a life cycle impact assessment of OPC concrete, recycled aggregate concrete, geopolymer concrete, and recycled aggregate-based geopolymer concrete by using the mid-point approach of the CML 2001 impact-assessment method. The life cycle impact assessment was carried out using OpenLCA software with nine different impact categories, such as global warming potential, acidification potential, eutrophication potential, ozone depletion potential, photochemical oxidant formation, human toxicity, marine aquatic ecotoxicity, and freshwater and terrestrial aquatic ecotoxicity potential. Subsequently, a contribution analysis was conducted for all nine impact categories. The analysis showed that using geopolymer concrete in place of OPC concrete can reduce global warming potential by up to 53.7%. Further, the use of geopolymer concrete represents the reduction of acidification potential and photochemical oxidant formation in the impact categories, along with climate change. However, the potential impacts of marine aquatic ecotoxicity, freshwater aquatic ecotoxicity, human toxicity, eutrophication potential, ozone depletion potential, and terrestrial aquatic ecotoxicity potential were increased using geopolymer concrete. The increase in these impacts was due to the presence of alkaline activators such as sodium hydroxide and sodium silicate. The use of recycled aggregates in both OPC concrete and geopolymer concrete reduces all the environmental impacts

A Sustainable Graphene Based Cement Composite

The rheological properties of fresh cement paste with different content of graphene nanoplatelets (GNPs), different shear rate cycles and resting time was investigated. The rheological data were fitted by the Bingham model, Modified Bingham model, Herschel–Bulkley model and Casson model to estimate the yield stress and plastic viscosity, and to see trend of the flow curves. The effectiveness of these rheological models was expressed by the standard error. Test results showed that yield stress and plastic viscosity increased with the increase in the content of graphene in the cement based composite and resting time while the values of these parameters decreased for higher shear rate cycle. In comparison to control sample, the GNP cement based composite showed 30% increase in load carrying capacity and 73% increase in overall failure strain. Piezo-resistive characteristics of GNP were employed to evaluate the self-sensing composite material. It was found that, at maximum compressive load, the electrical resistivity value reduced by 42% and hence GNP cement based composite can be used to detect the damages in concrete. Finally, the practical application of this composite material was evaluated by testing full length reinforced concrete beam. It was found that graphene–cement composite specimen successfully predicted the response against cracks propagation and hence can be used as self-sensing composite material

Influence of Graphene Nanosheets on Rheology, Microstructure, Strength Development and Self-Sensing Properties of Cement Based Composites

In this research, Graphene oxide (GO), prepared by modified hammer method, is characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) Spectrometry and Raman spectra. The dispersion efficiency of GO in aqueous solution is examined by Ultraviolet-visible spectroscopy and it is found that GO sheets are well dispersed. Thereafter, rheological properties, flow diameter, hardened density, compressive strength and electrical properties of GO based cement composite are investigated by incorporating 0.03% GO in cement matrix. The reasons for improvement in strength are also discussed. Rheological results confirm that GO influenced the flow behavior and enhanced the viscosity of the cement based system. From XRD and Thermogravimetric Analysis (TGA) results, it is found that more hydration occurred when GO was incorporated in cement based composite. The GO based cement composite improves the compressive strength and density of mortar by 27% and 1.43%, respectively. Electrical properties results showed that GO-cement based composite possesses self-sensing characteristics. Hence, GO is a potential nano-reinforcement candidate and can be used as self-sensing sustainable construction material

A Biomineralization, Mechanical and Durability Features of Bacteria-Based Self-Healing Concrete—A State of the Art Review

Cracking is one of the main ways that concrete ages, allowing pollutants to seep within and potentially lowering the physical and mechanical strength and endurance of concrete structures. One of the healing procedures that merits research is the use of bacterially generated calcium carbonate precipitation in concrete mixtures to mend concrete cracks. The impact of different variables, including the nucleation location, bacterial type, concentration, uratolytic activities, pH, nutrition, and temperature on the bio-mineralization of calcium carbonate are discussed in this review article. ATR-IR (Attenuated Internal Reflectance Fourier Transform Infrared Spectroscopy)/FTIR (Fourier Transform Infrared Spectroscopy)/NMR (Nuclear Magnetic Resonance) and FESEM (Field Emission Scanning Electron Microscope) are among the micro test techniques reviewed along with the biosynthetic pathway of bio mineralized calcium carbonate. The sealing ability and recovery of mechanical and durability properties of bio-mineralized concrete specimen is discussed. Moreover, we discussed the corrosion, damages, and challenges and their detection methods. Also, in-depth knowledge on the use, advancements, and drawbacks of bio-mineralized calcium carbonate is presented. Future potential for bio-mineralized (MICP) self-healing concrete are discussed in the final section

Flexural behaviour of steel hollow sections filled with concrete that contains OPBC as coarse aggregate

Oil-palm-boiler clinker (OPBC) is an agricultural waste from the palm oil industry and is considered a serious threat to the environment. Moreover, the high consumption of concrete as a construction material results in a continuous demand for natural aggregates, thereby negatively affecting the environment. Thus, channeling OPBC waste materials into the concrete industry aids in promoting the use of a sustainable and lightweight member. This research presents a novel sustainable composite beam that uses an OPBC as a replacement of the natural coarse aggregate. Flexural behaviour of steel tubes infilled with conventional and OPBC concretes were investigated. The results showed that the ductility, flexural stiffness and structural efficiency were higher in the OPBC concrete filled steel tube (CFST) than conventional CFST by 15%, 12% and 20%, respectively. Furthermore, in comparison to conventional CFST, the 10% less self-weight in OPBC CFST will significantly reduce the construction cost of the material. Conclusively, the utilisation of OPBC as infill material for CFSTs will solve disposal problem, preserve natural resources, reduce environmental pollution and will make the structural system sustainable