Waste Glass Alteration Processes, Surface Layer Evolution and Rate Limiting Steps

ABSTRACTThis paper provides an overview of waste glass alteration. Emphasis is on the evolution of surface layers and factors affecting the alteration rate when glass is subjected to an aqueous environment. The extent, type and rate of alteration is determined by a variety of parameters including time, temperature, glass composition, pH, Eh, composition of leachate/geology, the presence of other engineered barriers, flow conditions and surface area/volume ratio. Models (based on kinetic and thermodynamic considerations) developed by other researchers that are consistent with the experimental observations from the laboratory and field experiments are discussed. The morphology of the surface layers as described by interpretation of secondary ion mass spectrometry (SIMS) analyses on waste glasses and the role the various layers play in the alteration process is presented as well.</jats:p

Post-peak cyclic behavior of steel fiber reinforced concrete under bending

The paper deals with an experimental study on the fatigue behavior of plain and Steel Fiber Reinforced Concrete (SFRC). The research was carried out by studying the fatigue behavior of cracked concrete by means of three point bending tests. The effects of two different fiber contents and three different load levels were investigated and the fatigue performances of plain and SFRCs are compared. Despite the variable information regarding the fatigue behavior of concrete reported in the literature, this research study highlights that the inclusion of fibers can improve the fatigue performance of SFRC for high tensile stresses, guaranteeing a longer structural life. © RILEM 2012

Effectiveness of Anchorage in Concrete Beams Retrofitted with Sprayed Fiber-reinforced Polymers

This paper presents the result of an experimental study conducted to investigate the effectiveness of anchorage in concrete beams retrofitted with sprayed fiber- reinforced polymers (SFRP). It was intended to investigate whether the anchorage was an effective method to enhance the bond between the repair system and the application face. The anchorage is based on the idea of embedding the ends of the SFRP layer into preformed slits in the concrete so that the SFRP layer and anchors behave as a body. A series of three-point bending tests were conducted on notched plain concrete specimens retrofitted with SFRP layer and anchors. The test results were compared with those of control specimens and specimens retrofitted with SFRP without anchors to compare the performance enhancement between specimens with and without anchorage. The results show that the bond between the application face and the SFRP was sufficient enough to transfer the loads in the specimen to the repair system. The anchorage was not essential to enhancing the performance of concrete beams retrofitted with SFRP