Experimental Study of the Compressive Strengths of Basalt Fiber-Reinforced Concrete after Various High-Temperature Treatments and Cooling in Open Air and Water

The rapid development of modern society has increased the demand for high-performance geo-materials. As an advanced cementitious composite, fiber-reinforced concrete has attracted much attention and has been widely applied to various buildings and civil infrastructure. A basalt fiber-reinforced concrete is proposed as an advanced geo-material and the mechanical and thermal properties were investigated in this study. The basalt fiber-reinforced concrete was compared with ordinary concrete to confirm its superiority by determination of the physical parameters, static compressive test, and dynamic compressive test. The static compressive test was performed using the YAW-2000C constant stress pressure experimental machine under different heating temperatures and cooling methods, while the dynamic compressive test was performed using the 75-mm split-Hopkinson pressure bar under different loading rates, heating temperatures, and cooling methods. For the basic physical parameters, it was found that the mass loss and wave velocity of concrete decrease with the increase of the temperature. In the static compressive test, the static compressive strength for both the ordinary concrete and the fiber-reinforced concrete decreased with the increase of the temperature, and greater strength was observed with the air-cooled compared to the water-cooled method. It was found that the strength of basalt fiber-reinforced concrete is greater than that of ordinary concrete. In the dynamic compressive test, the strength increased with an increasing loading rate and descended with an increasing temperature, while for the same heating temperature and loading rate, water cooling produced more irregular and smaller fragments than air cooling. The dynamic compressive strength of basalt fiber-reinforced concrete was bigger than that of ordinary concrete.

Evaluation of the compressive and anti-penetration properties of Ti-Al3Ti-Al laminated composites

In order to further improve the mechanical properties of Ti-Al3Ti laminated composites, the endothermic semisolid reaction was used to fabricate Ti-Al3Ti-Al laminated composites, and the quasi-static compressive test, dynamic compressive test, and the ballistic penetration test were conducted on these composites. The results showed that the compressive strength and failure strain of Ti-Al3Ti-Al laminated composites prepared at 660°C are 1432 MPa and 35%, respectively. The dynamic response of these composites has obvious strain rate effect, and the crack grows in the shape of “Z.” The V50 of Ti-Al3Ti-Al targets is 509 m s−1. To sum up, Ti-Al3Ti-Al laminated composites have better mechanical properties and anti-penetration properties compared to Ti-Al3Ti laminated composites.

Dynamic Compressive Test and Rate-Dependent Constitutive Model of Microconcrete

The dynamic compressive tests of microconcrete were carried out under the strain rate of seismic action. Based on test results, the rate-dependent compressive constitutive model of microconcrete was proposed. In order to verify the accuracy and efficiency of the proposed constitutive model, the dynamic compressive tests of microconcrete were simulated by finite element software ABAQUS. Results show that the dynamic compressive strength and elastic modulus of microconcrete increase with the increasing strain rate. There was no obvious change on strain at peak stress. The compressive stress-strain curves of microconcrete were similar to concrete. The results of numerical simulation approximately agree with test results. The proposed constitutive model can simulate the dynamic compressive property of microconcrete very well.

Dynamic Deformation and Fracture Behavior of Zr-Based Bulk Metallic Glasses

Dynamic deformation and fracture behavior of Zr-based bulk metallic glass (BMG) and BMG composite containing dendritic β phases was investigated in this study. Dynamic compressive test results indicated that both maximum compressive stress and total strain of the BMG and BMG composite decreased with increasing test temperature because shear bands could propagate rapidly as the adiabatic heating effect was added at high temperatures. Above the glass transition temperature, total strain decreased more abruptly due to crystallization of amorphous phases. Maximum compressive stress and total strain of the BMG composite were higher than those of the BMG because β phases played a role in forming multiple shear bands. The BMG composite having more excellent dynamic properties than the BMG can be more reliably applied to the structures or parts requiring dynamic properties.