Applied Mechanics and Materials Vols. 174-177

Abstract: Recycled aggregate concrete technology has been payed widely attention. In addition to the research on the basic performance of recycled aggregate concrete, the impact resistance performance of recycled aggregate concrete was also involved. Through mixing respectively steel fiber, polypropylene fiber and steel-polypropylene hybrid fiber into the recycled aggregate concrete, the writer studied the impact resistance performance of fiber-reinforced recycled aggregate concrete, and compared the influence of reinforced fiber on the impact resistance performance of recycled aggregate concrete.

Abstract: Because the fly ash will produce large amounts of the secondary waste emission after the extraction of aluminum, the utilization of the fly ash residue after the extraction of aluminum has great significance. The autoclaved fly ash bricks studied in this paper use CFB ash residue after extraction of aluminum as the main material, and calcium carbide clay which consists mainly of calcium hydroxide is the waste residua of the production of acetylene gas in the chemical plants. This paper analyzes the chemical composition, the mineral composition and the microstructure of the fly ash residue after extraction of aluminum. In the paper, we also study the law and impacts of compressive strength, flexural strength, frost resistance and water absorption, which are made by calcium carbide clay for the autoclaved fly ash bricks. Experimental results illustrate that calcium carbide clay can significantly improve the compressive strength, the flexural strength and the frost resistance of the coal fly ash autoclaved bricks, and significantly reduce its water absorption.

Abstract: In this study, one new function is defined as change of relative crystallization degree in unit time and named relative crystallization rate (1/min.). The curve of heat flow rate to time is transmitted to that of to . The produced curve was fitted using one high-order polynomial equation with a variable of and the coefficient vector （Ai ,in this paper，the values of i were from 0 to 9）was produced. It was found that, even during the accelerated stage of crystallization from PET melt，both aspects to promote and delay the relative crystallization rate existed， furthermore， both aspects of promotion and delay declined with the crystallization process and appeared “internal exhaustion”.

Abstract: The mechanical properties and toughening mechanism of basalt fiber reinforced concrete (BFRC) with different fibers proportion ranging from 0 to 2.5 kg/m3 were tested in the experiment. The results show that the basalt fiber has little effect on the compressive strength of BFRC, but it can improve the impact toughness of BFRC significantly. Taking impact toughness as criterion, BFRC with 0.36% basalt fiber would be the best choice. The energy absorption characteristic of BFRC with different fibers dosages increases by 1.4~3.1 times than that of plain concrete when it is ultimately destroyed. Basalt fiber provides a secondary micro-reinforced system to BFRC when added into cement matrix. BFRC specimens show multi-cracking characteristics in the failure process, and the vice crack near the main crack is clearly observed while the final destruction.

Abstract: The MTS810 and SHPB are used to experimentally study the quasi-static and dynamic mechanical properties of three-dimensional E-glass fiber-reinforced composite. Stress-strain curves along the plane and thickness direction are obtained under varying strain rates, ranging from 10-3 to 103s-1. Experimental results show that strain rate has a significant effect on the material response. It is found that the compressive strength and the modulus increase with increasing strain rate, the failure strain, however, decreases slightly. But, the effect of strain rate in-plane and through thickness directions is different. A higher strain rate sensitive modulus and failure is found in the thickness direction, while a higher strain rate sensitive failure strength is found in the in-plane direction.

Abstract: The sandwich external wall panel is made of fireproof Paper Honeycomb Board (PHB) as kernel material, and the external surface is covered by colorful extruded steel board, while the internal surface is coated with the thermal insulating frothing ceramic board or the calcium silicate board, which works as the insulating layer or protecting layer of the panel. Two types of formation design are suggested, i.e., Type-A and Type-B. After corresponding thermal calculation, the maximum thermal transmission factor is determined as 0.424W/(m²• K), which complies with the threshold stipulated in the National Code for external wall panel used in cold climate area. The newly designed wall panel will save 65% of energy when compared with the traditional one made in 1980.

Abstract: The model tests have been done to verified the reasonable proportion of the fireproof concretes; the test result was analyzed, the compressive strength of the fireproof concretes after heating higher than the common concretes, the fireproof concretes which admixed with the polypropylene textile fiber, the silica flour and the carbon fiber can prevent the blowout of the concretes.

Abstract: The main mineral component of HuNan ChenZhou iron ore tailings is quartz, fluorite, calcite, pyroxene, etc. The average particle size of the tailings is 0.15mm, -200 for the purpose of 6.30 percent. Using the tailings as the aggregate, 42.5R ordinary cement as the gelled material, HTD-1 as foaming agent and other addition agent for prepared foam concrete, m(cement):m(tailing):m(additive):m(vesicant)=1:(1~2.3):(0.02~0.2):(0.005~0.09). At the standard curing conditions its performance fully meet the requirements of B09 density range in JC/T 1062-2007 standard and the strength range for the A5.0.

Abstract: According to the unified theory of general concrete filled steel tube, this paper puts forward a constitutive relationship model of the self-stressed concrete filled steel tube, which was verified by experiments and finite element methods. On the basis of the above, the influences on the bearing capacity of self-stressed CFST members were analyzed about the strength grades and magnitudes of self-stress of confined concrete. The results show that the bearing capacity of the self-stressed concrete filled steel tube members will be improved with the increase of the magnitudes of self-stress and concrete strength grades. Compared to the general CFST in the same condition, the maximum of the bearing capacity can be approximately enhanced 20%.

Abstract: This paper studies the effects of different water-cement ratio on recycled concrete strength, anti-carbonation capability, and protecting reinforce steel bar capability. Select the water-cement ratio 0.6,0.55,0.5,0.45,0.4 five cases of the pilot study.It shows that: recycled concrete cube compressive strength, anti-carbonation capacity and protecting reinforce steel bar capability are less than ordinary concrete.