Mechanical Properties of Carbon Fiber-Reinforced Polymer Concrete with Different Polymer-Cement Ratios.

To study the effect of redispersible polymer emulsion powder on the mechanical properties of carbon fiber-reinforced polymer concrete (CFRPC), the compressive, flexural, and splitting tests of CFRPC specimens with different polymer-cement ratios (polymer-cement mass ratios) were performed in this study. The modification effect of emulsion powder on CFRPC was analyzed from the perspectives of the strength and deformation properties of the specimens. The results show that the static properties of CFRPC increased first and then decreased with the increase of the polymer-cement ratio, in which the splitting tensile strength had the most significant increase; the flexural strength took second place and the compressive strength had a slight increase. When the polymer-cement ratio was 8%, the flexural and splitting tensile strength of the CFRPC specimens increased significantly by 36% and 61%, respectively. According to electron microscopy images, adding emulsion powder can effectively improve the structure of fiber-matrix transition zones and enhance the bond property between fibers and the matrix.

Developing a Polypropylene Fabric, Silica Fume, and Redispersible Emulsion Powder Cementitious Composite for Dynamic Water Environment.

In the dynamic water environment, grouting requires a material with higher strength and anti-washout performance to prevent groundwater inrush. This study aims to develop a dynamic water slurry by mixing polypropylene fiber (PP fiber), silica fume (SF) and the polymer material of redispersible emulsion powder (REP) to the Portland cement. Towards this aim, a series of tests, including strength, gel time, bleeding rate, fluidity, and anti-washout, were conducted to evaluate the effects of SF, PP fiber, and REP on the slurry properties. The test results show that: (1) SF displays significant effects on strength, gel time, fluidity, and bleeding rate of cement slurry. Differently, PP fiber mainly affects the stress⁻strain behavior of the slurry and can improve the ductility significantly. (2) By mixing SF and fiber simultaneously, the slurry strength can increase by about 30%, and its strain can extend by more than 70%. Meanwhile, the composite slurry possesses great anti-washout properties at a low flow velocity (v ≤ 0.4 m/s), and the grouting retention rate (GRR) can reach up to 98.7%. However, the GRR decreases to a maximum value of 31.3% when v = 0.6 m/s. (3) By mixing the REP into the fiber-SF composite slurry, the GRR can further increase, reaching more than 60% even when v = 0.6 m/s. As a result, the developed fiber-SF cementitious composite slurry, which when mixed with REP, presents a favorable performance in the dynamic water environment.

Influence of glycation on microencapsulating properties of soy protein isolate-lactose blends.

BACKGROUND: There is increasing interest in developing encapsulating materials from vegetable proteins as an abundant alternative for animal proteins or petroleum-derived polymers. Relationships between emulsifying and microencapsulating properties of soy protein isolate or blends with carbohydrates have not been well characterised. The influence of glycation between soy protein isolate and lactose prior to emulsification on the emulsifying and microencapsulation properties of their blends was investigated in this work. RESULTS: Analysis of the emulsion characteristics indicated that the glycation resulted in a decreased size of emulsion droplets, enhanced emulsion stability, and decreased apparent viscosity, suggesting improvement of emulsifying properties. In the spray-dried emulsions, the treatment with increasing degree of glycation from 0 to 13% progressively increased the retention efficiency from 96.4 to 98.3%. The glycation with an appropriate degree of glycation significantly decreased mean droplet size of the reconstituted emulsions, and increased the dissolution rate and capacity. However, the storage stability of the powders at 75% relative humidity was decreased by the glycation, though to a limited extent. CONCLUSION: Glycation improves the encapsulation efficiency, redispersion and dissolution properties of soy protein isolate-lactose blends, but slightly accelerated the storage instability of the spray-dried emulsions. The improvement of microencapsulation properties has been related to that of the emulsifying properties.