This study investigated the chemical properties of peat microparticles modified asphalt (Pt.M.A.). The originality of the study resides in the examination of the chemical characteristics of peat microparticles (Pt.) modified asphalt (Pt. M.A.) utilising FTIR, SEM, SFE, and XRD methodologies. This encompasses Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), surface free energy (SFE), and X-ray diffraction (XRD). Initially, FTIR examined the functional groups of both unaltered and altered asphalt binders. The SEM images reveal improved compatibility, showcasing superior diffusion of the modifier across the asphalt. A further critical factor is that improved adhesion properties, according to the SFE study, indicate that modified binders generally offer more SFE compared to unmodified binders. The XRD measurements revealed a semi-crystalline structure in the Pt. modifier and an amorphous structure in the basal asphalt binder. The integration of Pt. into the asphalt cement resulted in modifications to the phases of both constituents, culminating in the emergence of a new semi-crystalline phase inside the modified asphalt binder. These data suggest that peat microparticles (Pt.) can improve the efficacy of asphalt binders by enhancing compatibility, adhesion, and resistance to ageing.
The majority of experimental and analytical studies on fiber-reinforced polymer (FRP) confined concrete has largely concentrated on plain (unreinforced) small-scale concrete columns, on which the efficiency of strengthening is much higher compared with large-scale columns. Although reinforced concrete (RC) columns subjected to combined axial compression and flexural loads (i.e., eccentric compression) are the most common structural elements used in practice, research on eccentrically-loaded FRP-confined rectangular RC columns has been much more limited. More specifically, the limited research has generally been concerned with small-scale RC columns, and hence, the proposed eccentric-loading stress-strain models were mainly based on the existing concentric-loading models of FRP-confined concrete columns of small scale. In the light of such demand to date, this paper is aimed at developing a mathematical model to better predict the strength of FRP-confined rectangular RC columns. The strain distribution of FRP around the circumference of the rectangular sections was investigated to propose equations for the actual rupture strain of FRP wrapped in the horizontal and vertical directions. The model was accomplished using 230 results of 155 tested specimens compiled from 19 studies available in the technical literature. The test database covers an unconfined concrete strength ranging between 9.9 and 73.1 MPa, and section's dimension ranging from 100-300 mm and 125-435 mm for the short and long sides, respectively. Other test parameters, such as aspect ratio, corner radius, internal hoop steel reinforcement, FRP wrapping layout, and number of FRP wraps were all considered in the model. The performance of the model shows a very good correlation with the test results.