This article reports the durability performance of modified concrete with silica nanoparticles and a high volume of waste ceramic tiles under varying elevated temperatures. Ordinary Portland cement (OPC) was replaced with 60% waste ceramic tiles powder (WTCPs) and supplemented with 2, 4, 6, 8, and 10% nanopowders from waste glass bottles (WGBNPs) as a rich source of silica. The natural aggregates (both coarse and fine) were fully replaced by the crushed waste ceramic tiles (WTCAs). After 28 days of curing, the modified specimens were exposed to varying elevated temperatures (200, 400, 600, and 800 °C) in a furnace followed by air cooling. Tests such as residual compressive strength, weight loss, ultrasonic plus velocity, visual appearance, and microstructural analysis were conducted. Additionally, analysis of variance (ANOVA) was used to validate the performance of the proposed predictive equations, as well as their terms, using p-values and F-values. It was discerned that OPC substitution with WTCPs and WGBNPs significantly improved the concrete’s performance under elevated temperatures. It is observed that the addition of 2, 4, 6, 8, and 10% WGBNPs lowered the concrete deterioration by increasing the residual strength and reducing both internal and external cracks. This study provides some new insights into the utilization of WTCPs and WGBNPs to produce sustainable and eco-friendly modified concrete with high spalling resistance characteristics at elevated temperatures.

Geopolymers are a new breed of construction materials that are environmentally friendly and replace old Portland cement. These materials are produced through the alkaline activation of industrial and agricultural waste rich in aluminosilicates. The growing interest in sustainable building solutions has driven research into their development. Palm oil fuel ash (POFA) and waste ceramic tile powder (WTCP) are both highly rich in reactive aluminosilicates and widely recommended for the production of sustainable geopolymers. This study aims to evaluate the suitability of POFA and WTCP as sustainable alternatives to conventional binders and to identify the potential advantages of each waste material in developing eco-friendly, high-performance geopolymers. The results indicate that specimens prepared with a high content (50 wt%) of POFA or WTCP, incorporating fly ash and slag, can achieve compressive strengths of up to 50 MPa after 28 days of curing. However, increasing the proportion of POFA or WTCP from 50% to 60% and 70% resulted in a significant reduction in compressive strength. In contrast, specimens containing higher proportions of POFA and WTCP demonstrated superior durability when exposed to aggressive environments. In summary, the findings indicate that WTCP is more suitable than POFA for producing geopolymers as eco-friendly construction materials. Its superior reactivity, workability, early-age strength development, and durability make it a promising precursor for sustainable applications in the construction sector.

Replacing Ordinary Portland Cement (OPC) with high volumes of fly ash (FA) offers a practical approach to reducing the environmental impacts associated with cement manufacturing and landfill disposal. However, high FA replacement levels, particularly up to 60%, often lead to lower early-age strength. This study developed a green cement mortar containing 60% FA and waste bottle glass nanoparticles (WBGNPs). The WBGNPs were incorporated at replacement levels of 2%, 4%, 6%, 8%, and 10% by volume of the OPC–FA binder. The findings showed that the addition of 4–6% WBGNPs significantly promoted the formation of dense reaction gels and enhanced compressive strength by 12.5–39.1%. Similar performance trends were observed in both the engineering and microstructural properties. The combined incorporation of FA and WBGNPs also improved drying shrinkage performance by reducing capillary stresses during water evaporation and minimizing crack development within the cement matrix. Additionally, a proposed shrinkage prediction model was validated using experimental data and demonstrated good agreement, with an average prediction error of approximately 8%. Overall, the incorporation of WBGNPs provides an effective method for producing high-volume FA cement mortars with satisfactory engineering properties suitable for concrete applications in tropical environments. This approach further supports sustainability by reducing waste generation, lowering landfill demand, and minimizing environmental pollution.

Fire endorsement for elevated temperatures is a key factor in building safety. The insufficiency of fire resistance may be overcome by selecting a suitable pozzolanic material to restore the degradation. This study evaluates the use of a byproduct from the iron industry, Ground Granulated Blast Furnace Slag (GBFS), as a partial replacement for cement. GBFS has been used at different levels, ranging from 10% to 40%, as a partial replacement for Ordinary Portland Cement (OPC) and exposed to elevated temperatures. The proposed concrete, after 28 days of curing, was subjected to 500 °C and 900 °C for a 1-hour duration (soaking time at the peak temperature) using an automatic electric furnace and then air-cooled to conduct strength loss, weight loss, and UPV tests. The modified concrete incorporating GBFS showed higher durability performance compared to the conventional concrete. The strength and weight loss of 20% GBFS-modified concrete reduced at 18.9 and 81.4% to 13.1 and 78.3 % at 500 and 900 °C, respectively, while the UPV recorded a reduction to 1437 m/s compared with specimens with no GBFS (1295 m/s) at 500°C. This enhancement can be attributed to the production of more C-(A)-S-H gel, which fills voids within the concrete matrix and enhances its stiffness. In general, the enhanced resistance to elevated temperatures may improve safety by limiting damage and early collapse.

Total shrinkage, encompassing both drying and autogenous shrinkage components under standard drying conditions, is one of the most important factors affecting the long-term durability and serviceability of concrete structures. However, accurately predicting shrinkage behavior in nanomodified concrete remains a significant challenge. This study proposes an improved predictive framework for estimating the total shrinkage strain of carbon nanotube (CNT)-reinforced concrete. The developed model extends the CEB MC90 shrinkage model by incorporating critical CNT-related parameters, including CNT content, aspect ratio, and type, together with the water-to-cement ratio. The proposed framework was validated using experimental results. Additionally, a Monte Carlo simulation comprising 100,000 stochastic realizations was performed to evaluate the influence of uncertainties in key input variables, namely curing time, water-to-cement (w/c) ratio, CNT content, CNT aspect ratio, and CNT type. The simulation quantifies the success probability, defined as the likelihood that the total shrinkage strain of CNT-reinforced concrete remains within acceptable design limits (i.e., achieving at least a 10% reduction compared to plain concrete). The results demonstrate that the enhanced model provides accurate predictions of total shrinkage, with overall prediction errors of approximately 2% for plain concrete and 5% for CNT-modified concrete. The findings also show that the incorporation of CNTs effectively reduces total shrinkage by refining the cementitious matrix and improving internal restraint within the composite. Consequently, the proposed probabilistic prediction model offers a practical and reliable tool for optimizing CNT-reinforced concrete mixtures, enabling shrinkage to remain within acceptable design limits while improving long-term dimensional stability and structural durability.

Geopolymer materials have attracted considerable interest due to their economic, engineering, and environmental advantages. As global industrialization intensifies and infrastructure demands increase, the need for sustainable and alternative construction materials has become more urgent. Despite the considerable potential of Bottle Glass Powder (WBGP) incorporating Ground Blast Furnace Slag (GBFS)-based geopolymer materials, further research is required to improve their mechanical properties, reduce porosity, and enhance their resistance to elevated temperatures through effective modification of the binder system. In response to this challenge, the present study aims to develop high-performance geopolymer mortars by incorporating silica fume (SF) as a partial replacement for GBFS, with the goal of improving the performance of WBGP-based geopolymer systems. These were activated using a low-molarity sodium hydroxide solution in combination with sodium silicate and subsequently cured at ambient temperature. The influence of varying SF content on the mechanical, physical, and microstructural characteristics of WBGP-based geopolymer was evaluated using flexural, compressive, and tensile strength measurements, along with advanced analytical techniques, including XRD and FTIR. Furthermore, the durability characteristics of the developed geopolymer, including porosity and resistance to elevated temperatures (800 °C), were evaluated. The findings indicated that incorporating 3% and 6% SF as a replacement for GBFS enhanced strength performance. At the optimal mix containing 6% SF, the reported results showed enhanced bond strength between binder components, yielding a compressive strength of 36.2 MPa after 56 days, compared with 29 MPa for the control specimen. The substitution of GBFS by 6% of SF substantially reduces the geopolymer porosity and increases its resistance to elevated temperatures. These results offer valuable guidance for incorporating SF into the design and formulation of WBGP-GBFS geopolymer mortars, adding to the progression of sustainable and high-performance construction materials.