Performances of high performance polymer modified concrete for mining engineering
Although ordinary concrete is used in mining engineering, it has many defects such as high brittleness and low flexibility. It is urgent to exploit a kind of high performance polymer modified concrete for mining engineering which has low cost price, high performance, high bond strength, great convenience and excellent durability. Mechanical properties and durability were studied on ordinary concrete, concrete with polyacrylic acid latex and concrete with polyacrylic acid, styrene-acrylic two latexies and silica fume. The results are as follow. First, compression strength of concrete with polyacrylic acid latex is lower than that of ordinary cncrete. And its rupture strength, tensile splitting strength, bond strength and impermeability is higher by 28.6%, 37.5%, 55.3% and 77.2% than ordinary concrete respectively. Second, concrete with polyacrylic acid, styrene-acrylic two latexies and silica fume has higher compression strength than common concrete. At the same time, its rupture strength, tensile splitting strength, bond strength and impermeability is higher by 48.8% 53.1% 73.0% and 83.3% than ordinary cncrete respectively. So, it is called high performance polymer modified concrete. Third, it was analysed by scanning electron microscope. Last, the experiments in a mine shows that its performances and bond strength with tunnels are higher than ordinary concrete while its price is only higher by 0.6% for 1 stere concrete.
Composite mechanism of polymer modified cement
Abstract Microstructure and composite mechanism of polymer modified cement (PMC) and mortar have been studied. Microstructure of PMC was observed by cryo-SEM. Dispersed polymer particles were observed in the hardened body. Polymer films were observed on the surface of hardened samples and at the interface of cement or aggregate in PMC. The bending strength of PMC was increased by the action of soft polymer particles in the hardened body. Adhesive strength of PMC was improved by the formation of polymer films. Both the particle dispersion of polymer and the formation of polymer films are useful as the composite mechanism of PMC.
Simulating the Illuminance and Efficiency of the LEDs Used in General Household Lighting
Abstract The advantage of the LEDs illumination in general household lighting was proposed. High efficiency white LED as the light source was provided the energy saving illumination of the general household lightings. Different spaces in general household with different standards of average illuminance were designed and simulated by LightTools and DIALux software. The power consumptions and efficiency of traditional illuminated light sources and LED light source in lighting the household environment were analyzed and compared with each other at the same standard of average illuminance. Finally, it provided the advantage of using white LEDs in different spaces of the general household lighting.