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Geochemical, mineralogical and sedimentological analyses were carried out on sands erupted from sand volcanoes and soil cracks during the 2012 Emilia earthquakes with the aim of determining their origin and depth of provenance in a complex stratigraphic plain generated by different fluvial contributions. Geochemical, mineralogical and sedimentological analyses were performed by wavelength dispersive X-ray fluorescence, X-ray powder diffraction and Sedigraph and Settling tube, respectively. Distinct textural features, as well as Ni/MgO and Cr/Al2O3 ratios, allow discriminating two populations: an A-area located close to San Carlo village and a B-area nearby Scortichino village. Sediments from A-area show chemical and mineralogical characteristics well comparable with those of the sediments derived from the Apennine rivers, whereas sands from B-area have strong similarities with the sediments from the Po river. In the earthquake crater area most of the liquefaction phenomena were related to superficial sandy deposits (fluvial ridges, paleochannels and crevasse splays) generated by Apennine rivers. The Po river sediments in the B-area derive from a layer at a depth at which liquefaction phenomena were excluded, because of the greater lithostatic load. These sediments thus shed a new light on the mechanisms that may induce liquefaction during an earthquake or even without a seismic triggering. It is suggested that a gas phase (mainly methane),which is commonly found belowthe Po plain, could have been dissolved in the water, near to the saturation threshold or already exsolved, increasing the interstitial overpressure and facilitating the liquefaction and the eruption of the sandy sediments. [ABSTRACT FROM AUTHOR]

The influence of coal fly ash and glass fiber waste on the tensile strength of cement concrete was studied using central composite design. Coal fly ash was used to replace 10% of the cement in the concrete mix. Glass fiber was added to improve the tensile properties of the concrete in different dosages and lengths. In total, 14 mixes were investigated, one only with 10% coal fly ash replacement of cement and the other thirteen were determined by the experimental design. Using analysis of variance, the order of importance of the variables was established for each property (flexural strength and split tensile strength). From the nonlinear response surfaces, it was found that higher values of flexural strength were obtained for fibers longer than 12 mm and at a dosage of 1-2%. For split tensile strength, higher values were obtained for fibers with a length of 19–28 mm and at a dosage of 1–1.5%. [ABSTRACT FROM AUTHOR]