Abstract: The potential stabilization of high calcium wood waste ash (HCWWA) derived from the wood biomass energy production for use as cementitious material using another industrial by-product, silica fume, was investigated. Throughout the study, both HCWWA and DSF were characterized in term of their respective chemical composition and mineralogical phases. Besides, physical characteristics of HCWWA and DSF in terms of particle grading and specific surface area were established in order to evaluate their suitability as for use as constituent material in blended cement. Additionally, compressive strength properties of high strength mortar produced using HCWWA and DSF blended cement were investigated. Results indicated that the use of HCWWA as a partial cement replacement did not have significant adverse effect on the workability of fresh mortar. The enhancement of the compressive of mortar was observed for mortar mixes containing DSF and HCWWA levels of cement replacement up to 16%.
Abstract: Management of solid wastes is one of the most important issues around the world. Vehicle tires are one of these solid wastes. A test program was carried out to determine the mechanical properties of rubberized concretes with and without silica fume and polypropylene fiber. The main objective of this study was to investigate the use of silica fume in cement composite containing waste rubber tire. In the present work the Silica fume was replaced by 10% of cement weight. Five designated rubber content varying from 10% to 50% by volume and polypropylene content 0.3% by volume were used. The 28-days properties of the cement composite were determined. The analyses included compressive strength, flexural strengths, velocity of ultrasonic wave, water absorption and Scaning electron microscopy(SEM). The results indicated the following points: Increase in rubber content decreases the sample unit weight, the introduction of rubber particles significantly increas the strain capacity of the materials and the use of silica fume increas the mechanical properties.
Abstract: This paper presents a laboratory study on the properties of rice husk ash (RHA) cement composite mortars incorporating nano-SiO2. Different amounts of nano-SiO2 (0%, 1%, 3% and 5%) were incorporated into the mortars with 20% replacement of RHA. The compressive and flexural strengths of mortars were tested at 7, 28, 60 and 90 days. The water absorption test carried out at 28 days. The drying shrinkage of mortars was measured up to the age of 42 days. Scanning electron microscopy (SEM) observation also conducted to evaluate the effect of nano-SiO2 on microstructure of cement paste containing RHA. Incorporating nano-SiO2 into RHA mortars significantly improved the mechanical strength and water absorption properties of the products. Nano-SiO2 increased the drying shrinkage of RHA mortars. SEM analysis showed that nano-SiO2 improved the microstructure of RHA pastes on dense and compact form.
Abstract: A designed experimental study has been conducted to investigate the effect of the fiber fraction of polypropylene fiber on the mechanical properties of concrete containing fly ash, a large number of experiments have been carried out in this study. The mechanical properties include compressive strength, splitting tensile strength and compressive modulus of elasticity. On the basis of the experimental results of the specimens of six sets of mix proportions, the mechanism of action of polypropylene fiber on these mechanical properties has been analyzed in details. The results indicate that there is a tendency of increase in the compressive strength and splitting tensile strength, and the modulus of elasticity of concrete containing fly ash decrease gradually with the increase of fiber volume fraction with appropriate content.
Abstract: A designed experimental study has been conducted to investigate the effect of polypropylene fiber on the compressive strength and flexural properties of concrete containing silica fume, a large number of experiments have been carried out in this study. The flexural properties include flexural strength and flexural modulus of elasticity. On the basis of the experimental results of the specimens of six sets of mix proportions, the mechanism of action of polypropylene fiber on compressive strength, flexural strength and flexural modulus of elasticity has been analyzed in details. The results indicate that there is a tendency of increase in the compressive strength and flexural strength, and the flexural modulus of elasticity of concrete containing silica fume decrease gradually with the increase of fiber volume fraction.
Abstract: Windows are one of the most significant elements in the design of buildings. Whether there are small punched openings in the facade or a completely glazed curtain wall, windows are usually a dominant feature of the building's exterior appearance. From the energy use perspective, windows may also be regarded as thermal holes for a building. Therefore, window design and selection must take both aesthetics and serviceability into consideration. In this paper, using building computer simulation techniques, the effects of glass types on the thermal and energy performance of a sample air-conditioned office building in Australia are studied. It is found that a glass type with lower shading coefficient will have a lower building cooling load and total energy use. Through the comparison of results between current and future weather scenarios, it is identified that the pattern found from the current weather scenario would also exist in the future weather scenario, although the scale of change would become smaller. The possible implication of glazing selection in face of global warming is also examined. It is found that compared with its influence on building thermal performance, its influence on the building energy use is relatively small or insignificant.
Abstract: In this research, the mechanical and fracture behaviours of concrete containing waste CD shreds were investigated using the three-point bending notched beam test, according to RILEM recommendations. The size effect of waste CD shred on concrete properties was the focus of this research. The study indicates that the fracture energy and modified characteristic length were found to increase significantly with increasing the size and volume fraction of CD shreds due to anchoring and bridging effects. In other words, concrete with higher amounts and larger sizes of CD shreds exhibit higher cracking resistance and the brittleness decreases accordingly. However, the strength properties were found to decrease when concrete with larger portion and size of CD shreds.
Abstract: This paper studies the recycling of solid waste concrete of the foundational content. Through the experimental research on the use of recycled aggregate and recycled concrete powder, I propose recycled coarse aggregate, recycled powder of various physical and chemical characteristic and the powder mixed with cement slurry mixed with recycled coarse aggregate on the surface of the mechanical properties after treatment. The results show that the coarse aggregate crushing value after surface treatment, strength characteristics of concrete can meet the requirements of ordinary concrete.
Abstract: A side platform with screen door was studied in this article using the computational fluid dynamics software FDS5.0, a 3D model of the side platform was built with a fire located close to one end wall in the platform. Large Eddy Simulation model (LES) was used to assess the effect of mechanical smoke exhausting under the different ventilation modes. The analysis of temperature field and CO concentration in the platform showed that the exhaust in fire zone mode can improve the ability of single vent, reduce the disturbance to the smoke layer, and the smoke exhaust effect is better than the other modes.