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ABSTRACTThis study investigated the effects of a crystalline admixture (CA) and superabsorbent polymer (SAP) on the self-healing and mechanical properties of basalt fibre mortars. Uniaxial compression experiments were conducted on basalt fibre mortar specimens to investigate the effects of the two admixtures and different admixture ratios on the strength repair ability of basalt fibre mortar at different maintenance ages after pre-cracking, and microscopic observations of cracks and their healing products were conducted using optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy to verify the experimental results. The results showed that CA has a noticeable advantage in the self-healing of microcracks by producing a dense material through chemical reactions, whereas SAP can effectively fill wider cracks and reduce their width through physical expansion. Compared with CA, SAP had a greater effect on the compressive strength of the basalt fibre mortars. The simultaneous dosing of CA and SAP in appropriate amounts can effectively combine the advantages of CA and SAP to optimise the self-healing effect of basalt fibre mortars, generating self-healing fillers based on calcium silicate and calcium carbonate in the cracks and enhancing the repair strength of basalt fibre mortars with a self-healing rate of 103%.

Objective: This study aims to evaluate the effectiveness of a nomogram model constructed using Diffusion Kurtosis Imaging (DKI) and 3D Arterial Spin Labeling (3D-ASL) functional imaging techniques in distinguishing between cerebral alveolar echinococcosis (CAE) and brain metastases (BM). Methods: Prospectively collected were 24 cases (86 lesions) of patients diagnosed with CAE and 16 cases (69 lesions) of patients diagnosed with BM at the affiliated hospital of Qinghai University from 2018 to 2023, confirmed either pathologically or through comprehensive diagnosis. Both patient groups underwent DKI and 3D-ASL scanning. DKI parameters (Kmean, Dmean, FA, ADC) and cerebral blood flow (CBF) were analyzed for the parenchymal area, edema area, and symmetrical normal brain tissue area in both groups. There were 155 lesions in total in the two groups of patients. We used SPSS to randomly select 70% as the training set (108 lesions) and the remaining 30% as the test set (47 lesions) and performed a difference analysis between the two groups. The independent factors distinguishing CAE from BM were identified using univariate and multivariate logistic regression analyses. Based on these factors, a diagnostic model was constructed and expressed as a nomogram. Result: Univariate and multivariate logistic regression analyses identified nDmean1 and nCBF1 in the lesion parenchyma area, as well as nKmean2 and nDmean2 in the edema area, as independent factors for distinguishing CAE from BM. The model's performance, measured by the area under the ROC curve (AUC), had values of 0.942 and 0.989 for the training and test sets, respectively. Calibration curves demonstrated that the predicted probabilities were highly consistent with the actual values, and DCA confirmed the model's high clinical utility. Conclusion: The nomogram model, which incorporates DKI and 3D-ASL functional imaging, effectively distinguishes CAE from BM. It offers an intuitive, accurate, and non-invasive method for differentiation, thus providing valuable guidance for subsequent clinical decisions.

This study examines the changes in the micro- and nano-structures of microwave-cured cement and slag pastes over 7 years. The properties of aged samples were compared with those of young pastes made from the same mixtures. Both young and aged samples were analyzed by XRD, DTA-TG, SEM-EDX, and Solid-state MAS NMR of 29Si and 27Al. It is found that, in addition to the usual components (C-S-H, calcium hydroxide, monosulfoaluminate, trisulfoaluminate, and hydrotalcite-like phases (HT)), the aged samples contained calcium magnesium aluminate hydrate and gibbsite (AH3). Over time, some HT or AH3integrated into the C-S-H nanostructure as additional layers. These findings suggest that microwaves accelerate the general hydration processes in cement due to thermodynamic effects and selectively activate reactions in the aluminate components. This discovery highlights the potential for using microwaves to manipulate cement reactions.

This paper presents an investigation on the adoption of isothermal microwaving in curing ultra-high performance concrete (UHPC) embedded with steel fiber reinforcement. The plain UHPC and the one with varying levels of steel fiber reinforcement are developed by microwave heating at 80 °C for 30 min. The compressive and flexural strength, hydration products, microstructure and interfacial structure of the mixes are evaluated. The results show that, besides the common reactions of hydration, pozzolanic reaction, carbonation, a reaction consuming calcium carbonate is found to occur in the system; furthermore, a Hayne-like phase and a cancrinite-like phase are formed. The formation of them is reduced by increased reinforcement. The accelerated effects of microwave on reaction are found to vary with reinforcement. Accelerating hydration is beneficial from increased fiber contents. Steel fiber reinforcement is more effective in increasing the compressive and flexural strength of UHPC cured with microwaves than cured under standard conditions.