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The current study investigates the potential of various waste materials and industrial by-products for formulating high-recycled content hydraulic cement, leveraging alkali aluminosilicate chemistry principles. Through rigorous characterization employing X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, thermogravimetric analysis (TGA), and Scanning Electron Microscopy (SEM), alongside alkalinity and alkali solubility assessments, the chemical and mineralogical compositions of waste brick, lime kiln dust, cement kiln dust, waste glass, gypsum, foundry sand, granulated blast furnace slag, and impounded coal ash were unveiled. Silicon and aluminum were found abundantly in these materials, with lime kiln dust and slag contributing calcium. A thoroughly crafted blend, enriched with alkalis, underwent mechanochemical activation to yield a hydraulic cement finely tuned to meet specific chemical ratios required for effective alkali aluminosilicate reactions. Upon hydration, this innovative cement exhibited rapid early strength development, achieving a commendable compressive strength of 32 MPa within 28 days a performance on par with standard Portland cement. Remarkably, the heat of hydration profiles revealed a prompt onset of hydration reactions, marked by a significant exothermic peak within the initial hours, in contrast to the gradual peak observed with Portland cement. TGA/DTA results further corroborated the thermal stability of the hydration products formed. Alkali-solubility assessments of the raw materials emerged as reliable indicators of their reactivity within the cement matrix, with solubility values exceeding 20 % for waste glass and impounded coal ash, signifying their high potential for alkali activation. The culmination of this research underscores the feasibility of re-composing waste materials to craft alkali aluminosilicate cement, offering performance akin to conventional options. These findings advocate for the adoption of sustainable material utilization in construction, paving the way for enhanced industrial symbiosis in cement production. • Novel research on alkali aluminosilicate cement offers a sustainable alternative to traditional cement. • Thorough characterization using advanced techniques unveils the chemical and structural properties for further exploration. • Early-age strength gain, reaching 32 MPa, highlights its potential for applications requiring rapid strength development. • TGA/DTA analysis reveals thermal stability and potential reactivity of hydration products towards long-term performance. [ABSTRACT FROM AUTHOR]

Ultra-high-performance concrete (UHPC) surpasses normal strength concrete in engineering properties such as durability under extreme conditions, strength, and ductility characteristics. However, the dense structure, impermeable nature, and lack of capillary pores in ultra-high-performance concrete may diminish its resistance to spalling when subjected to intense heating conditions, unlike normal and high-strength concrete. The behavior of UHPC under such conditions has not been extensively researched, especially in the context of engineering properties and spalling behavior. Existing knowledge is primarily inferred from normal and high-strength concrete behavior under high temperatures, but this approach has sparked contention due to differing phenomena at play. Given ultra-high-performance concrete's distinct composition and excellent mechanical features, the principles applied to normal and high-strength concrete may not sufficiently explain its complex behavior during thermal exposure, particularly regarding spalling and engineering properties. Furthermore, enhancing its fire resistance becomes increasingly crucial as UHPC gains popularity in new and existing structures. To bridge this knowledge gap, this review paper presents various facets of UHPC during intense heat exposure, emphasizing engineering properties, fire-induced spalling, its factors, underlying mechanisms, microstructural analysis, performance, and preventative and remedial strategies. Future research recommendations are also offered to improve UHPC's performance under elevated temperatures, potentially leveraging current knowledge in the field. • Adding fibers can mitigate spalling in UHPC. • Dense microstructure of UHPC helps lower spalling. • Intense heat can cause explosive spalling, if not treated well. [ABSTRACT FROM AUTHOR]

[Display omitted] • A systematic review investigating the effects of various nanomaterials and thin films on properties and microstructure of green concrete. • Emphasis on the importance of characterization techniques in understanding properties and performance of geopolymer nanomaterials and thin films. • Identification of current limitations, and future research goals in nanomaterials and thin films for concrete. • Potential applications of nanomaterials and thin films include advanced coatings for corrosion protection, fire resistance, and electronic devices and sensors. • Valuable insights and knowledge for researchers and industry professionals to enhance sustainability using NMs and thin films. Concrete, a common building material, mostly contains cement. Cement production utilizes much energy, depletes natural resources, and emits carbon dioxide. Efforts are being made to create concrete without cement. In this regard, developing geopolymer composite as a viable novel construction material creates a better substitute for sustainable building practices. This study presents a systematic review to examine recent and ongoing research to explore the impacts of various nanomaterials (NMs) and thin films (TF) on geopolymer composite's hardened properties and microstructure. In this context, thin films, specialized layers of material applied to the surface of green concrete, typically with a thickness ranging from nanometers to micrometers, are considered. These films may contain various NMs to enhance or modify the concrete's properties and microstructure. The importance of characterization techniques such as XRD (X-ray diffraction), SEM (Scanning Electron Microscopy), and FTIR (Fourier-transform infrared spectroscopy) is emphasized, as they play a crucial role in understanding the properties and performance of geopolymer nanomaterials and thin films. A large database, including the key attributes of geopolymer composites with NMs and thin films, was created using data from more than 158 published studies. Furthermore, the research identifies current accomplishments, limitations, and future research goals in nanomaterials and thin films for green concrete. These advancements are expected to significantly impact emerging fields, with potential applications ranging from advanced coatings for corrosion protection and fire resistance to functional electronic devices and sensor surfaces. This comprehensive review contributes to the advancement of green concrete technology and the development of sustainable construction materials. The insights gained from this study and the created database provide valuable knowledge for researchers and industry professionals, facilitating the adoption of NMs and thin films to improve the performance and sustainability of concrete in construction. [ABSTRACT FROM AUTHOR]