The rapid growth of Natural Fiber Laminate (NFL) innovation is a direct response to environmental challenges, positioning these materials as superior alternatives to synthetic fiber composites. This paper delved into the outcomes of an extensive experimental study investigating the influence of sisal fiber (SLF), banana fiber (BF), and glass fiber (GF) on the mechanical and microstructural characteristics of concrete. The water absorption curves were established for sisal fiber concrete (SLFC), banana fiber concrete (BFC), and glass fiber concrete (GFC). Furthermore, Scanning Electron Microscope (SEM) observations were conducted to perform microanalysis and failure analysis of the tested specimens. The results revealed significant improvements in the concrete containing fibers compared to its counterpart in fiber-free concrete. For mixtures with a water-to-binder (W/B) ratio of 0.3, the most optimal mix (GF-30-135) showed improvements in compressive strength, flexural strength, and splitting tensile strengths by 4.13%, 8.93%, and 10.10%, respectively. On the other hand, for W/B of 0.4, mix GF-30-135 showed improvements of 5.05%, 8.55%, and 11.60%, respectively. Furthermore, as the fiber content increased, microscopic analyses revealed a weakening of the bond between the fibers and the rest of the matrix, contributing to the deterioration of the mechanical properties.

A versatile building material, foamed concrete is made of cement, fine aggregate, and foam combined with coarse aggregate. This study provides a description of how constant coarse aggregate replacement (50%) of LECA and foamed concrete, which are lightweight concrete types, by zeolite as a filler and PEG-400 as a plasticizer, water retention agent, and strength enhancer affect the mechanical properties of the cement. A study that examined the characteristics of cellular lightweight concrete in both its fresh and hardened forms was carried out for both foamed concrete and LECA concrete. In order to do this, a composite of zeolite and polyethylene glycol 400 was made using the direct absorption method, and no leakage was seen. Zeolite was loaded to a level of 10% and 20% of the total weight in cement, while 400 g/mol PEG was used at levels of 1%, 1.5%, and 2% of the cement’s weight. Various mixtures having a dry density of 1250 kg/m³ were produced. Properties like dry density, splitting tensile strength, and compressive strength were measured. An increase in the amount of PEG400–zeolite was seen to lower the workability, or slump, of both foamed and LECA concrete, while the replacement of aggregate by zeolite resulted in an exponential drop in both compressive and flexural strengths.

Concrete structures in marine environments face significant degradation due to reinforcement corrosion caused by chloride ingress and sulfate attack. Poor construction quality, inadequate standards, and suboptimal design can further accelerate deterioration. Non-destructive testing (NDT) has proven valuable for durability assessment, yet its application remains limited due to the complex microstructural characteristics of concrete. This study establishes a comprehensive procedure for evaluating precast concrete degradation in marine environments using multiple characterization techniques. Two precast concrete elements with different cement types, CEM II A-L 42.5R and CEM I 42.5 R/SR, were analyzed through compressive strength tests, open porosity measurements, mercury intrusion porosimetry (MIP), ultrasonic wave transmission, and scanning electron microscopy (SEM). The results indicate that CEM I 42.5 R/SR exhibits superior compressive strength and lower porosity, making it more durable and suitable for load-bearing applications. Higher ultrasonic pulse velocity (UPV) further confirms its resilience. In contrast, CEM II A-L 42.5R shows lower mechanical performance and greater susceptibility to marine-induced degradation. Over time, pore size distribution shifts, potentially compromising mechanical integrity. SEM analysis reveals gypsum and brucite formation in degraded regions, demonstrating microstructural changes due to seawater exposure. A strong negative correlation between porosity and UPV underscores the detrimental effect of increased porosity on material density and structural stability. This study highlights the effectiveness of UPV and porosity analysis as reliable NDT techniques for assessing concrete deterioration. The strong correlation between UPV and porosity trends suggests that UPV serves as an early indicator of durability loss, enabling timely maintenance interventions. These findings provide valuable insights into material selection for enhanced structural performance in marine environments and emphasize the role of NDT in long-term structural health monitoring.

Self-healing concrete provides an eco-efficient approach for restoring cracks through autonomous repair, reducing maintenance demands and enhancing long-term durability. This study evaluates concrete incorporating Bacillus subtilis bacteria and sisal fibers to examine their individual and combined effects on mechanical performance and microstructural development. Bacterial cells at a concentration of 2 × 10⁸ CFU/mL were introduced with calcium lactate as a nutrient source at varying dosages, while sisal fibers were added at a volume fraction of 0.9%. Concrete mixes containing 0%, 2.5%, and 5% bacterial content were tested under fresh-water curing. Compressive, splitting tensile, and flexural strengths were assessed at multiple ages, accompanied by SEM and EDS analyses to investigate healing products and microstructural alterations. Bacteria-enhanced mixes demonstrated improved long-term compressive behavior, with B5/5/1 reaching 50.1 MPa at 56 days, while higher bacterial content slightly reduced early-age strength but benefited later performance. Incorporating sisal fibers consistently improved mechanical resistance, notably in combination with bacteria. The SB5/5/1 mix achieved 55.2 MPa at 56 days, representing a 30% gain over the control. Tensile strength was particularly influenced by fibers, with SB10/5/1 recording 6.3 MPa at 56 days (≈70% increase). Flexural strength results similarly highlighted the superior behavior of hybrid systems, where SB10/5/1 attained 9.2 MPa (+67%), reflecting enhanced self-healing efficiency even under challenging curing conditions.

This study investigates the potential use of tire-derived carbon black “N-330” as a sustainable waste binder in asphalt concrete mixtures, combined with resin as an alternative to the usual binding material in asphalt mixtures, “bitumen”. With the increasing demand for environmentally friendly construction materials, this research aims to assess the feasibility of incorporating resin tire carbon black N-330 “RTCB N-330” into asphalt as a full replacement for conventional binders. A comprehensive experimental program has been designed to evaluate the mechanical and performance properties of asphalt mixtures containing varying proportions of RTCB N-330, ranging from 2% to 10% by weight of the binder. The impact of replacing bitumen with resin that contains TCB N-330 on the physical, rheological, and thermal characteristics of RTCB N-330 as a modified asphalt binder is assessed in this study. To assess the binders, a number of tests were carried out, including standard tests for ductility, the softening point, and penetration. DTG (Derivative Thermogravimetric Analysis) and testing the thermal susceptibility index were performed. A higher percentage of TCB N-330 reduced the penetration while increasing both the softening point and ductility. Resin with 8% of TCB N-330 was the optimum percentage, which was compared with bitumen as a new environmentally friendly binder. The testing program involved the preparation of asphalt concrete specimens using a Marshall mix design, followed by a Marshall Stability test to evaluate the deformation resistance of the modified mixtures. The results were anticipated to demonstrate that incorporating N-330 into asphalt mixtures can enhance stability. The Marshall test results indicated that samples with 6% resin tire carbon black as the binder percentage “AC-RTCB6” demonstrated the highest stability among all RTCB samples. Moreover, these samples outperformed asphalt mixtures using bitumen as the binder in terms of stability. Also, the AC-B mixes exhibited lower flow values compared to the AC-RTCB mixes. The higher flow observed in the AC-RTCB specimens suggests that the addition of 1.5% xylene as a solvent to the resin was effective and positively influenced the flow characteristics.

This research intends to investigate and analyze the usage of Jordanian oil shale ash (OSA) as a replacement material for ordinary Portland cement and pozzolanic cement in mortar. To start, oil shale was collected from the Wadi Al-Shallala location, crushed, sieved and burned at 800 °C for 24 h. OSA partially replaced the ordinary Portland and pozzolanic cements with ratios of 10%, 20%, and 30%. This research looked into the effect of cement substitution on the standard consistency and hardening time for cement paste. The water contents as well as beginning and final hardening times increased due to the higher replacement ratios of the cements. Also, pozzolanic activity index (PAI) along with scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) testing and mechanical properties (compressive and flexural strengths) of mortar with both types of cement substitution were evaluated. The compressive strength and flexural strength were checked following 3, 7, 14, 28, 56 and 90 days of curing, while (SEM) was conducted just at 28 days old with a 20% replacement ratio in mortar specimens. Results show that 20% OSA substitution for ordinary Portland cement or Pozzolanic cement raises compressive strength and flexural strength, plus provides better morphology. Thus, oil shale is seen as a natural pozzolanic material that increases efficiency in cement mixtures.