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Valorizing agricultural residues as cement-free binders may reduce dependence on Portland cement. However, the performance of silica-rich biomass ashes under alkali activation remains insufficiently understood. This study explores the effects of alkali activator-to-binder ratio (Al/B), curing temperature, and age on mortars containing Phragmites australis ash (PAA) as the sole binder. Specimens with Al/B ratios of 1.0, 1.1, and 1.2 were activated with sodium silicate and 12 M sodium hydroxide (SS/SH ratio of 2.5) and cured at 20, 40, and 80 °C. Flow, density, ultrasonic pulse velocity, flexural strength, compressive strength, and dimensional stability were evaluated. Compared with the Portland-cement control, PAA mortars showed lower flow and mechanical performance, but densities remained below 1500 kg/m³ under all curing conditions. Increasing Al/B significantly increased flexural and compressive strengths at 28 days. Elevated-temperature curing significantly increased ultrasonic pulse velocity and both strengths. The maximum PAA compressive strength was 4.67 MPa at 90 days after curing at 80 °C, representing a reduction of 62%. PAA mortars showed higher drying and autogenous shrinkage with increases of 8.5–9.5% and 2.9–4.4%, respectively. However, PAA mixes resulted in lower chemical shrinkage than the control mix, by around 0.2–0.6%. The present results suggest that PAA can be used as a low-density non-structural mortar in non-load-bearing applications, subject to durability and component-scale studies.

Despite the large volumes of marbleized limestone processing waste (MLPW) generated by the stone industry, its utilization in the production of high-strength masonry materials remains limited, and systematic comparative studies of white and gray Portland cements in hyperpressed MLPW-based bricks are scarce. In this study, four mixture formulations containing MLPW (70–85 wt.%), white Portland cement (CEM I 52.5, M500) or gray Portland cement (CEM I 42.5, M450), and water were prepared at a constant water-to-cement ratio of 0.25. Specimens were manufactured by hyperpressing under compaction pressures of 28 and 41 MPa and cured for 7 days in a sealed moist environment. The formulations compacted at 28 MPa achieved compressive strengths corresponding to brick strength grades M350 and M400. Increasing the pressure to 41 MPa yielded grades M400–M550 with white cement; under identical conditions with gray cement, grades M400 and M450 were attained. Among the tested formulations, those containing 75–80 wt.% MLPW (20–16 wt.% cement) showed the most favorable combination of compressive strength and density. The mechanical performance correlated well with the microstructural features observed by scanning electron microscopy (SEM) and EDS analysis. The average density of all specimens exceeded 2100 kg/m³, classifying the materials as heavyweight concrete. The novelty of this work lies in the comparative evaluation of white and gray Portland cements in hyperpressed MLPW bricks and the establishment of relationships between compaction pressure, binder type, overall mixture composition, and resulting strength grades. The results demonstrate a promising route for converting high volumes of industrial marble waste into high-strength masonry units. However, further investigation of durability-related parameters, including water absorption, frost resistance and flexural strength, is required before the practical application of the developed materials can be fully evaluated.

Bridge structural health monitoring (SHM) depends on sensor streams that may contain missing blocks, noise, spikes, drift, and recorded faults. We evaluated a frozen, group-aware stress testing protocol on 64 Vänersborg bridge opening events and 153 processed Z24 scenario × setup traces. Models used healthy training data only; degradations were restricted to held-out groups. Area under the receiver operating characteristic curve (ROC-AUC) and average precision (AP) were co-primary metrics. Vänersborg principal component analysis (PCA) baseline AUC and AP values were 0.500/0.454, respectively. In addition, 20% missingness yielded 0.188 and 0.327 (paired changes −0.313 and −0.126), and 0.5% spikes yielded 0.058 and 0.298 (−0.442 and −0.156), respectively. Z24 PCA baseline AUC and AP values were 0.731 and 0.929, respectively, and the studied perturbations changed both metrics only slightly. Under event power-scaled 5 dB noise, Vänersborg PCA AUC decreased by 0.221, while the other detectors increased. A new label-blind sensitivity analysis fixed one robust channel variance from the healthy training events. This equalized injected power across evaluation classes and changed the PCA ΔAUC to +0.075, showing that the original scaling asymmetry contributed materially to the detector-specific directions. Results are exact conditional summaries of two observed finite archives and do not establish universal quality, severity, or maintenance thresholds.