Sharif Digital Repository

Polymer concrete is well-known for quick repairing of concrete structures and pavement. However, there are relatively few studies on the durability of epoxy polymer concrete (EPC). This study aims to investigate the long-term environmental effects on the mechanical properties of EPC. Therefore, EPC and ordinary cement concrete (OCC) specimens were prepared and exposed to four chemical solutions with pH values of 2.5, 7, 12.5 and artificial seawater in intervals of 1, 3, 6, 9 and 12 months. Epoxy resin (10 and 12% by weight) and Portland cement were used as binder phase in EPC and OCC specimens, respectively. Scanning electron microscopy (SEM) was additionally applied to investigate the... 

Epoxy resins have been used as structural materials since the late 1940s. Despite their desirable properties such as high strength, excellent creep resistance, and good adhesion, they suffer from low fracture energy. Rubber modification as a major toughening approach to overcome the inherent brittleness of epoxy polymers was introduced during the early 1970s. Since then, a large number of investigations have been conducted to elucidate different aspects of rubber-toughened epoxies. The present work is a critical review of the field focusing on the important parameters affecting rubber-toughening. The studies reviewed are classified in five categories including roles of matrix ductility,... 

In this research, the effect of adding graphene-based aerogel ((G)A) nanoparticles on the tensile and fatigue behavior of the epoxy polymer was investigated. Specimens of nanocomposites were prepared by adding 0.05, 0.1, 0.2, 0.5, 1, and 2 wt.-% (G)A nanoparticles to the epoxy polymer. Tensile tests revealed that the 0.1 wt.-% graphene-based aerogel/ epoxy ((G)A/E) nanocomposites had the highest increase in tensile strength with 19 % growth compared to neat epoxy. Also, the tensile modulus increased by 15 % in the 0.5 wt.-% (G)A/E nanocomposites. A substantial improvement in fatigue life of the epoxy polymer was observed on adding 0.1 wt.-% (G)A nanoparticles. For instance, the fatigue life... 

The objective of this study is to investigate the effects of both rubbery phase and nanosilica on mechanical properties of epoxy. Three series of formulations based on epoxy including nanosilica, rubber and rubber/nanosilica were prepared. Transmission electron microscopy showed that nanoparticles were homogeneously dispersed throughout the epoxy matrix. Compression and fracture toughness tests along with scanning electron microscopy and transmission optical microscopy were also done to evaluate the properties of the compounds. Although the results of compression tests indicate that addition of nanosilica could not change elastic modulus and yield strength of neat resin significantly,...