Conventional glass/carbon fiber-reinforced polymer (G/CFRP) composites have been widely used for infrastructure applications in the past decades. Nowadays, there is a trend to use cost-effective and ductile FRP composites such as polyester FRP (PFRP). This paper presents the results of an experimental investigation on the compressive behavior of concrete confined by PFRP jackets with low strength and high ductility. Twenty-seven PFRP confined plain concrete and nine unconfined plain concretes were tested. The considered experimental variables included concrete strength and PFRP thickness. Test results indicated that the PFRP jacket confinement increased the ductility of concrete to a great extent. However, the confinement on the enhancement in concrete ultimate compressive strength is limited. In addition, some existing stress–strain models were used to predict the ultimate stress and compared with the experimental results, and new confinement models were also proposed for PFRP-confined concrete.

The paper investigates the effects of Cu particle size on diamond composites experimentally. The hybrid microwave sintering process is proposed to obtain the particle size microstructure throughout the rapid heating. The effects of Cu particles on the hardness, flexural strength, and thermal conductivity are experimentally investigated. The experimental results indicate that the Cu particle size has a significant impact on the physical and mechanical properties of the CuSnFeNi/diamond composites. The smaller the Cu particle size, the larger thermal conductivity, the hardness, and flexural strength are obtained. This study provides an effective means to enhance the mechanical properties of the CuSnFeNi/diamond composite by adjusting the Cu particle size.