Preparation of High-Ductility Cement-Calcined Coal-Gangue-Powder-Composite-Based Rapid Repair Material

Coal gangue is a kind of solid waste. A high-ductility cement-calcined coal-gangue-powder-composite-based rapid repair material (HD-RRM) was prepared by partially replacing cement with calcined coal gangue powder (CCGP) for achieving high ductility and rapid hardening and conforming to the strength requirements of pavement layers. First, the physical and chemical properties and the reactivity of the CCGP were investigated. Second, HD-RRM material was prepared, and its tensile performance characteristic parameters were investigated. Lastly, the hydration products and microstructure of HD-RRM were characterized through tests (e.g., non-evaporable water content, scanning electron microscopy (SEM), X-ray diffraction (XRD), and comprehensive thermogravimetric analysis and differential scanning calorimetry (TG-DSC)). As indicated by the experimental results, the CCGP with a particle size of 1250 mesh exhibited the maximum potential reactivity. The optimal mixing ratio for HD-RRM in the experiments comprised a water-cement ratio of 0.27, a sand-cement ratio of 0.3, a fiber volume fraction of 2%, a cement content of 70%, a CCGP content of 20%, a fly ash (FA) content of 10%, and a superplasticizer content of 0.1%. Using the abovementioned mix design, the prepared HD-RRM was endowed with a 6 h ultimate elongation of 2.75%, an ultimate tensile strength of 7.58 MPa, a compressive strength of 45.4 MPa, and an average crack width of 125.53 μm, which meets the requirements of repair materials and provides a design method for CCGP resource utilization and asphalt concrete road and bridge deck repair.

Experimental Study on Seismic Performance of Precast Columns Repaired with CFRP Fabrics

Earthquakes worldwide highlight the seismic vulnerability of reinforced concrete (RC) bridge columns. RC bridges are likely to collapse or lose service function due to damage to the bridge columns from strong earthquakes. Rapid repair of RC bridge columns is of great significance for maintaining traffic lines for emergency rescue work after earthquakes. In this study, an improved rapid repair method was developed to restore the bearing capacity of a damaged precast column after earthquake damage. A cyclic loading test was performed to simulate the seismic loading. The original column and the repaired column were both tested. The test results showed that the bearing capacity of the repaired columns was increased by 8%, and the energy dissipation capacity was 53% higher than that of the original column. The ductility decreased because the test for the repaired specimen ended in advance. The initial stiffness of the repaired columns was reduced, but the stiffness was significantly developed in the later loading stage. The rapid repair method proposed in this study exhibited an excellent effect on restoring the seismic resistance of the damaged columns.

Long-term behaviors of phosphate-based rapid repairing material for concrete shafts in coal mines

INTRODUCTION

Concrete structures in shaft linings are apt to deteriorate prematurely and therefore prompt restoration is required. In considering this, desulphurization fly ash and machine-made tuff sand are employed to fabricate a phosphate-based rapid repairing material.

METHODS

The long-term efficiency of the material is evaluated based on combined factors, so drying shrinkage, interfacial bonding strength, corrosion resistance, and combustibility of the specimens are tested and researched in this paper.

RESULTS

Experimental results showed that, under a dry circumstance, the material goes through a minor expansion at an early stage. It goes into a stage of rapid contraction after one day and a stable contraction after seven days. After 28 days, the total deformation is 67 micro-strains. On the other hand, the fabricated material manifests an excellent mechanical property. The one hour bending strength and compressive strength were 9.2 MPa and 32.6 MPa, respectively. A long-term mine water flushing simulation demonstrates that only 10% bending strength is lost and the corrosion resistance coefficient stays above 0.8, so a very good corrosion resistance is thus achieved.

CONCLUSIONS

What is more, this repairing material retains its stability even at a high temperature of 1000°C, revealing its good thermo-stability. All these prominent properties make it a good prospective material for real restoration applications.

Rapid bone repair in a patient with lung cancer metastases to the spine using a novel herbal medicine: A case report

The prognosis of lung carcinoma with metastasis to the bone, particularly to the spine, is poor. Chemotherapy and radiotherapy are established treatments for metastatic bone disease, but their effectiveness is unsatisfactory and bone repair following their use is slow and difficult. Medicine prepared from herbal extracts may be an alternative treatment option. The present study discusses the case of a 59-year-old patient diagnosed with squamous cell lung cancer (T2N3M1) in which first-line chemotherapy using docetaxel plus cisplatin failed. Heavy multiple bone metastases were detected in the T9 vertebra and sixth left rib, resulting in a high risk of pathological fracture. Eastern Cooperative Oncology Group (ECOG) and numerical rating scale (NRS) scores of pain were 2 and 4, respectively. A second-line treatment was chosen consisting of biological intracontrol treatment (BICT) plus bisphosphonates administered over 40 days. BICT is a therapy involving the use of herbal extracts (including ginseng, herba agrimoniae, hairyvein agrimonia herb, white flower patrinia herb and arginine) and palliative care. A partial positive response was reached following use of this regimen, particularly with regard to bone repair. A computed tomography scan revealed a 90% reduction in the broken area of the rib cage and T9 vertebra. The bone repair was rapid and almost complete. In addition, growth of the primary tumor in the right pulmonary hilar and metastasis in the mediastinal lymph nodes were stabilized following treatment. ECOG and NRS scores were decreased to 1 and 0, respectively, leading to an improved quality of life. Based on these results, the present study suggests that this herbal medicine-based regimen promotes bone repair and inhibits tumor growth, with low toxicity. However, the mechanism by which herbal medicine promotes rapid bone repair is unclear. Further studies are required to determine whether cells in the tumor microenvironment are stimulated to undergo re-differentiation by unidentified herbal substances.