Effect of Fly Ash on Drying Shrinkage of Thermal Insulation Mortar with Glazed Hollow Beads

Drying shrinkage of thermal insulation mortar with glazed hollow beads was measured by a vertical length comparator, and the influences of fly ash with different contents（0, 18%, 36%, and 54% were used） on the long-term drying shrinkage were discussed. The mass loss was measured by the weighting method and the pore structure was characterized using three different methods, including the light microscopy, the mercury intrusion porosimetry（MIP）, and the nitrogen adsorption/desorption（NAD） experiments, and the correlations among them were researched. The results show that drying shrinkage process of thermal insulation mortar includes three steps with increasing curing time： the acceleration period（before 7 d）, the deceleration period（7-365 d）, and the metastable period（after 365 d）. Drying shrinkage in the first stage（7 d before） increases quickly owing to the fast water loss, and its development in the last two stages is attributed to the increment of the pore volume of mortar with the radius below 50 nm, especially the increment of the pore volume fraction of the pore radius within the size range between 7.3 nm and 12.3 nm. There is no change in the drying shrinkage development trend of mortar with fly ash addition, and three steps in the service life, but fly ash addition in the mortar restrains its value. There is a linear relationship between the drying shrinkage and fly ash content, which means that drying shrinkage reduces with fly ash addition.

Compressive and Fracture Properties of Syntactic Foam Filled with Hollow Plastic Bead(HPC)

The compressive mechanical properties of syntactic foams reinforced by hollow plastic beads were studied by the quasi-static compression test. The failure mechanism of syntactic foams was also investigated by macroscopic and microscopic observation on the fractured specimens. The experimental results show that the density of syntactic foams is still the key factor affecting their mechanical properties. The macroscopic and microscopic observation on the fractured specimens indicates that the main failure mode is the elastic-plastic collapse caused by shear.

Photocatalytic degradation of PCP-Na with TiO_2 photocatalysis loaded with platinum

Titanium dioxide(TiO 2) samples of different crystal forms were prepared by hydrolysis tetrabutyl titanate in various water to alkoxide ratios and sintering the hydrolysis product at different temperatures. The photocatalysts coated on hollow glass beads and loaded with platinum varying from 0.2% to 2.4% by weight.The photocatalytic degradation rate of sodium pentachlorophenolate (PCP-Na) depends on the preparing conditions such as: sintering temperatures, water to alkoxide ratios( R ), platinum content and the size. The proper conditions of preparation photocatalysts are as follows: the ratio of TiO 2 : sodium silicate : hollow glass beads : platinum is 10:5:20:0.15(w/w), R is 100, sintering temperature is 650℃, and the size of hollow glass is 0.5-1 mm. Under these conditions, the ratio between acatase and rutile of the photocatalyst is 2:1, and the photocatalytic activity is high.

Thermal Analysis of Concrete Mixtures with Recycled EPS Aggregates

Reusing recycled waste materials in buildings is gaining more and more attention for what it offers economic,environmental,and energy benefits;and many researchers are nowadays working on producing new sustainable construction materials incorporating recycled wastes.In this scope,this work uses an experimental approach aiming at understanding the effect of incorporating Expanded Polystyrene(EPS)beads in concrete and proposing thermally improved concrete mixtures for the production of hollow blocks in Lebanese constructions by substituting fine aggregates with recycled products such as EPS in order to promote their insulating properties.Three different diameters of EPS beads(2 mm~3 mm,3 mm~4 mm and 4 mm~5 mm)are studied with different volumetric ratios(20%,40%,60%and 80%)in order to investigate the effect of EPS on the thermal properties of concrete.The results showed that the only the percentage of incorporated EPS beads impacted the thermal performance of the concrete mixtures while the EPS diameters have a negligible effect on the thermal properties of the concrete samples.