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Nanotechnology can be regarded as one of the new research fields having novelty and important applications that recently gained attention, especially during the last twenty years. The implementation of nanotechnology produces materials with novel characteristics and recently many works were conducted to include nanoparticles (NPs) in cement-based materials to improve performance and manufacture concrete with better behavior under different mechanical and environmental conditions. Previous studies demonstrated that different waste ashes such as, fly ash, cement kiln dust, palm oil fuel ash, eggshell ash, Metakaolin, and waste ceramic ash can be efficiently converted to sustainable nano ashes. The chemical and physical properties of the produced nano ashes were significantly different from their parent ashes. Therefore, the concrete produced with these nano ashes had superior properties compared to the normal concrete made with traditional waste ashes. This paper presents a systematic overview of the synthesis and characterization of different nano ashes and their impacts on the performance of concrete mixtures. Based on the results from the comprehensive review, it was illustrated that the specific surface to volume ratio was considerably increased by converting the ashes to nano ashes, thus the properties of concrete were also improved. Moreover, due to the higher specific surface area of nano ashes and their reaction with undesirable C-H which is present in the cement paste matrix to produce additional C-S-H, the microstructure of concrete was considerably enhanced.

Abstracts: Recently, Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) has offered notable advantages over other types of concrete. Therefore, a comprehensive investigation of the latest developments in Ultra-High-Performance Concrete (UHPC) is necessary to provide essential information for materials testing requirements and procedures and to expand its practical applications. The present work is a comprehensive four-part review of the UHPFRC. The current first part of the review focuses attention on the developments, principles, and raw materials of the UHPFRC. Part II covers the hydration and microstructure of the UHPFRC. Part III reviewed the fresh and hardened properties of the UHPFRC. Part IV covers the durability properties, cost assessment, applications, and challenges of the UHPFRC. This review is expected to advance the fundamental knowledge of UHPC and promote further research and applications of UHPC.

Abstracts: Ultra-high-performance concrete (UHPC) is a cement-based composite used for new construction and/or the restoration of existing structures in order to extend their service life. It is a revolutionary composite material that can serve as a suitable substitute for concrete construction in hostile environments. After decades of research and development, a wide variety of commercial UHPC compositions have been created around the world to meet the expanding number of uses and demand for high-quality building materials. Although UHPC has significant advantages over conventional concrete, its application is limited due to restrictive design rules and high cost. Therefore, a careful review of the various properties of UHPC is necessary to offer key information for material testing criteria and methods and to broaden its practical uses. “Part I reviewed the developments, principles, and raw materials of the UHPFRC. Part II reviewed the hydration and microstructure of the UHPFRC. Part III reviewed the fresh and hardened properties of the UHPFRC. Part IV covers the durability properties, cost assessment, applications, and challenges of the UHPFRC. This Part V covers the mixture design, preparation, mixing, casting, and curing of the UHPFRC.” This review is anticipated to increase the fundamental understanding of UHPC and encourage additional study and applications of UHPC.

Abstracts: Ultra-high-performance concrete (UHPC) refers to cement-based materials exhibiting a compressive strength higher than 150 MPa, high ductility, and excellent durability. Besides, over the last twenty years, remarkable advances have taken place in the research and application of Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC). Therefore, a comprehensive investigation of the durability characteristics of UHPC is essential to provide fundamental information for material testing requirements and procedures and expand its practical applications. Part I reviewed the developments, principles, and raw materials of the UHPFRC. This Part II covers the hydration and microstructure of the UHPFRC. Part III covers the fresh and hardened properties of the UHPFRC. Part IV covers the durability properties, cost assessment, applications, and challenges of the UHPFRC. This review is expected to advance the fundamental knowledge of UHPC and promote further research and applications of UHPC.

Abstracts: Ultra-high-performance concrete (UHPC) is a type of cement-based composite for new construction and/or restoration of existing structures to increase service life. It is an innovative composite material that can be a suitable alternative to concrete structures exposed to aggressive conditions. After decades of research and development, a wide range of commercial UHPC compositions have been produced worldwide to cover a growing number of applications and a growing demand for high-quality construction materials. UHPC has significant advantages over regular concrete, but its use is limited due to limited design codes and prohibitive cost. Therefore, a comprehensive investigation of the durability characteristics of UHPC is essential to provide fundamental information for material testing requirements and procedures and expand its practical applications. Part I reviewed the developments, principles, and raw materials of the UHPFRC. Part II reviewed the hydration and microstructure of the UHPFRC. Part III reviewed the fresh and hardened properties of the UHPFRC. This Part IV covers the durability properties, cost assessment, applications, and challenges of the UHPFRC. Part V covers the mixture design, preparation, mixing, casting, and curing of the UHPFRC. This review is expected to advance the fundamental knowledge of UHPC and promote further research and applications of UHPC.

Abstracts: Ultra-high-performance concrete (UHPC) refers to cement-based materials exhibiting a compressive strength higher than 150 MPa, high ductility, and excellent durability. Besides, over the last twenty years, remarkable advances have taken place in the research and application of Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC). Therefore, a comprehensive investigation of the durability characteristics of UHPC is essential to provide fundamental information for material testing requirements and procedures and expand its practical applications. Part I reviewed the developments, principles, and raw materials of the UHPFRC. Part II reviewed the hydration and microstructure of the UHPFRC. This Part III covers the fresh and hardened properties of the UHPFRC. Part IV covers the durability properties, cost assessment, applications, and challenges of the UHPFRC. Part V covers the mixture design, preparation, mixing, casting, and curing of the UHPFRC. This review is expected to advance the fundamental knowledge of UHPC and promote further research and applications of UHPC.

The manufacture of ordinary Portland cement (OPC) produces a lot of CO2 in the atmosphere. Researchers have recently focused on exploring the behaviour of geopolymer concrete (GPC) as an alternative to Portland cement concrete (PCC) in micro and macro dimensions. Geopolymers (GP) are innovative cement-based materials that could totally replace OPC composites. Geopolymer composites (GC) have a reduced carbon footprint and utilize less energy than OPC. The construction industry's main concerns are material characteristics and the performance of reinforced concrete (RC) structural components. Therefore, this review paper is going to look at some important material properties, like fresh characteristics, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity, as well as the evidence of the structural behaviour of GPC beams. According to the findings of this review, GPC offers similar or superior fresh and mechanical properties to conventional concrete composite. In addition, it was mentioned that GPC might be utilized to design GPC members securely in terms of their strength capabilities and standard codes of practice. Nevertheless, further study is suggested to include more detailed and cost-effective design methods for the potential use of GPC for large-scale field applications.

During the transition of one material from macro- to nano-range size, considerable changes occur in the electron conductivity, optical absorption, mechanical properties, chemical reacting activity, and surface morphology. These changes can be advantageous in the production of new mixture composites. Due to the need for developing improved infrastructure, new and high-performance materials should also be developed. In this regard, to improve the performance of concrete mixtures, several methods have been investigated, including using nanoparticles (NPs) to enhance various characteristics of the concrete composite like improving fresh and mechanical properties of self-compacting concrete (SCC) as well as improving permeability and absorption capacity of the composite by providing extremely fine particles to fill micro-pores and voids.In this paper, a state-of-the-art review was carried out on the influence of various NPs inclusion on the fresh, mechanical, and durability properties of self-compacting mortars (SCM). So that current and most recent studies previously published were investigated to highlight the influences of different NPs on the slump flow diameter, V-funnel flow time, compression and flexural strengths, water absorption, chloride penetration, and electrical resistivity. Moreover, the main section of this study was devoted to proposing different models, including nonlinear model (NLR), multi-logistic model (MLR), and artificial neural network (ANN), to predict the compressive strength (CS) of SCMs modified with NPs. Based on the analyzed data, it was illustrated that the addition of NPs into SCMs significantly enhances the fresh, mechanical, and durability performance of SCMs. Moreover, the microstructure of SCMs was considerably improved due to the higher specific surface area of NPs and their reaction with undesirable C–H which present in the cement paste matrix to produce additional C-S-H gel.

Since nanotechnology can enhance the performance of materials, significant effort has been expended in recent years to incorporate nanoparticles (NPs) into geopolymer concrete (GPC) to improve performance and produce GPC with improved characteristics. Recent efforts have been made to incorporate various nanomaterials, most notably nano-silica (nS), into GPC to improve the composite's properties. Compressive strength (CS) is an important property of all concrete composites, including geopolymer concrete. Several mix proportion parameters and curing temperature and ages influence the CS of geopolymer concrete. As a result, developing a credible model for forecasting concrete CS is critical for saving time, energy, and money while also providing guidance for scheduling the construction process and removing formworks. This paper consists of three phases; in the first phase, a detailed review on the effect of adding nS on the CS of GPC was provided; then, in the second phase, a large amount of mixed design data were extracted from literature studies to create five different models including artificial neural network, M5P-tree, linear regression, nonlinear regression, and multi logistic regression models for forecasting the CS of GPC incorporated nS. Finally, the developed models were validated in the last phase by carrying out experimental laboratory works. Results revealed that the addition of nS improves the CS of GPC, and the ANN model estimated the CS of GPC incorporated nS more accurately than the other models. On the other hand, the alkaline solution to binder ratio, molarity, NaOH content, curing temperature, and ages were those parameters that significantly influenced the CS of GPC incorporated nS.