Advanced Materials Research Vols. 671-674

Abstract: The activator is very important for the use of high volume fraction slag in cement so that the compressive strength of cement complying with the requirements of codes. A new slag activator, which is from the by-product of magnesium chloride industry, is investigated experimentally. The test results show that the addition of the new activator increases the compressive strength of cement containing 69% slag effectively. Compared to the compressive strength of the reference cement (no activator added), the compressive strength of the cement with the new activator increases about 40%. The new activator has the similar performance as calcium chloride, which is a conventional slag activator. With the new activator, the compressive strength of cement containing 69% slag meets the requirements of standard GB1344-1999.

Abstract: A serial of fire tests have been conducted to study the fire resistance of the post-installed rebar connection with organic adhesive. Research variables include three kinds of anchorage depth. Loads are applied to specimens through lever and remain a constant throughout the whole process of the tests. The temperatures of connections are elevated following the ISO834 curve and the failure is controlled by excessive deflection of bonded-in rebar beams. The test results show that anchorage depth has a great influence on the performance of bonded-in rebar beams exposed to fire. Beams using organic adhesive fail suddenly with obvious rebar slip, and behave with poor fire endurance.

Abstract: Nylon 6/MgAl-LDH nanocomposites had been successfully prepared by In situ hydrolyzed ring opening polymerization in this work. The structures and properties of Nylon 6/MgAl-LDH nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The nanodispersion of exfoliated MgAl-LDH layers in nylon 6 matrix has been verified by the observation of TEM image in Nylon 6/MgAl-LDH nanocomposites with 0.3 wt% MgAl-LDH (MANM-0.3). The XRD results showed that the exfoliated MgAl-LDH favored the formation of the γ-crystalline of nylon 6 form. DSC data showed that the exfoliated MgAl-LDH layers play the role of nucleating agents with strong heterogeneous nucleation effect on the crystallization of nylon 6. But TAG results showed the thermal stability of nylon 6/MgAl-LDH nanocomposites were worse than that of neat nylon 6.

Abstract: Dextrins are important starch derivatives, they are a kind of environmental biological materials and widely used in industry. The paper gave a full introduction about the definition, properties, application and the recent research situation of pyrolysis dextrin, cyclodextrin, maltodextrin and β-limit dextrin, their development tendency are also discussed.

Abstract: In this dissertation, we studied the mechanical behaviors of HDPE fiber reinforced in cement mortar. One of our major concerns is to study the utilization of high strength high density polyethylene (HDPE) fibers obtained from different draw ratio melt spinning processing. Another major concern is to compare these fibers in term of mechanical behavior reinforced in cement mortar. We began with the material characterization, which mainly include different draw ratios with two sets of rollers through a glyceral bath set at 113°C. Draw ratio was calculated from the ratio of the speed of the follower to leader roller. The latter studies largely used three different fiber volumes fraction ratio tested mechanical properties of cement mortar by using the universal testing machine follow on ASTM standard testing. Subsequently, we studied the behaviors of HDPE fiber reinforced in cement mortar, which mainly include the flexural, tensile and compression strength. The development of mechanical strength of cement mortar when added with these fibers were presented characterize of cement mortar.

Abstract: By studying the entries of Solar Decathlon Europe 2010，the thesis sums up the new trends of green building’s skin materials, which are adjustable building skin materials, innovative application of traditional materials, solar skin integrated with architecture, regional context and aesthetic expression of the building skin materials. It is expected that the study can provide some reference and inspiration for the development of green building.

Abstract: Added carbon powder or M mineral powder in unburned kaolinite coal gangue, the mixtures could be changed better expansive mineral additive of Portland cement by microwave irradiation. The microwave activation coal gangue mixtures 5%, 10%, 15%, 20%, 25%, 30% and 35% (by weight) were respectively added intoⅠ42.5 Portland cement. The compressive/flexural strength of various expansive coal gangue Portland cements were determined after 3 and 28 day. The fineness, initial and final setting time, soundness and volume expansive ratio was also measured. 　　　The expansive reasons of coal gangue Portland cement were considered that there were lots of thicker and bigger flaky crystal during hydration processes by scanning electron microscope, and found the Al, Si, O and other elements in flaky crystal by Edax. 　　　The expansive mechanism of coal gangue Portland cement is different from traditional expansive cements theories by microwave irradiation.

Abstract: With the rapid development of construction industry, the amount of architectural coatings, especially exterior wall coatings, is growing year by year. However, more common problems of construction quality arise with the increase of project amount. Exterior wall putty is leveling material of the protective layer, and putty fitting for external thermal insulation system should have a high bonding strength, good performance of crack resistance and excellent resistance to water. The basic material in this paper is cement and coarse whiting, talcum powder and quartz powder are the fillers. Then the basic mix of putty will be got through orthogonal experimental design. In order to improve the performance and research inorganic materials and associated auxiliary for external wall putty performance impact, pasty exterior wall putty can be prepared through mechanical mixing and by adding some relevant inorganic materials and auxiliaries. Results indicate that this kind of exterior wall putty is easy to burnish the powder and have good performances of workability, water resistance, high bonding strength and dynamic crack resistance. Which has better performances than that sold in market, especially for the performances of bond strength, dynamic crack resistance and water absorpution.

Abstract: Generally the high density in high-strength concrete results in high strength, and so people often mix superplasticizer and particulate to increase the density of concrete, but ignoring the effect of coarse aggregate gradation on concrete strength. Referring to several Gradation Theories, this paper selects the coarse aggregate gradation with skeleton, uses uniform design method to test the compressive strength of high-strength concrete, and analyses the test results. It can be known from the test results of 7d and 28d concrete specimen that the concrete strength decreases linearly with water-cement ratio and sand ratio; The 7d’s concrete strength has higher variability due to low water-cement ratio with superplasticizer; The coarse aggregate skeleton is interfered by the increase of steel slag and sand rate, and the concrete strength decreases with limited cement paste. Furthermore, the steel slag with less than 30% addition has little effect on concrete strength and it can increase the cement’s possibility of contacting to water, and reduce the amount of cement without lowering the concrete strength. The influential degree on the compressive strength of concrete is followed by ascending sequence of steel slag content, sand ratio and water-cement.

Abstract: Introduce a green energy-saving slump retaining agent synthesis process, the slump retaining agent on IR characterization molecules ，which structure and design of the basic ideal molecular structure match.Test results show that：When Point-S polycarboxylate superplasticizer slump retaining agent complex mass ratio of 1:0.2, 2h slump when the variation amount is 30mm, to prevent the excessive concentration of concrete hydration heat, reduce cracks in concrete.The slump retaining agent complex products in Ping An International Financial Centre C60 successful application of self-compacting concrete.