This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na<sub>2</sub>...This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na<sub>2</sub>CO<sub>3</sub>): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.展开更多
The present study was carried out at two different gradients of unbumt and burnt Anogeissus latifolia forest sites in the Garhwal region, India. At each gradient, the unburnt and burnt forest sites were further catego...The present study was carried out at two different gradients of unbumt and burnt Anogeissus latifolia forest sites in the Garhwal region, India. At each gradient, the unburnt and burnt forest sites were further categorized into three different elevations, i.e., lower （700 m）, middle （850 m） and upper （1000 m）. At each elevation, the density of trees, saplings and seedlings was higher at the unburnt sites except for trees at the upper elevation which was higher at the burnt sites. The total basal area of each layer of for- est was also higher at the unburnt sites. The study revealed that the lower number of saplings and seedlings at the burnt forest sites might be due to the effect of fire. Most trees in the lower dbh classes were affected by forest fire at the burnt sites which reduced the total density and total basal area of the trees compared to the unburnt sites. The diversity of trees increased with increasing elevation. However, the diversity of saplings and seedlings reduced with increasing elevation.展开更多
The manufacture of clean steel needs high performance carbon-free bricks for ladle lining.Based on long term application experiences of the prefab Al_(2)O_(3)-MgO blocks,unburnt Al_(2)O_(3)-MgO brick has been develope...The manufacture of clean steel needs high performance carbon-free bricks for ladle lining.Based on long term application experiences of the prefab Al_(2)O_(3)-MgO blocks,unburnt Al_(2)O_(3)-MgO brick has been developed by pressing a mix of alumina,spinel and magnesia as major raw materials and Al_(2)O_(3)-MgO gel powder as binder.In addition to low open porosity and high strength,the unburnt Al_(2)O_(3)-MgO brick shows superior corrosion resistance and thermal shock resistance to the prefab block.Field trials in a 300t steel ladle have indicated the residual lining of unburnt Al_(2)O_(3)-MgO bricks showed smooth surface without large spalling and seldom steel infiltration,consequently longer service life than the prefab blocks.The reliable,unburnt Al_(2)O_(3)-MgO bricks have more advantages of high efficiency,energy-saving and eco-friendly production.It will be one of the best options for ladle lining in the manufacture of high-purity steel.展开更多
文摘This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na<sub>2</sub>CO<sub>3</sub>): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.
文摘The present study was carried out at two different gradients of unbumt and burnt Anogeissus latifolia forest sites in the Garhwal region, India. At each gradient, the unburnt and burnt forest sites were further categorized into three different elevations, i.e., lower （700 m）, middle （850 m） and upper （1000 m）. At each elevation, the density of trees, saplings and seedlings was higher at the unburnt sites except for trees at the upper elevation which was higher at the burnt sites. The total basal area of each layer of for- est was also higher at the unburnt sites. The study revealed that the lower number of saplings and seedlings at the burnt forest sites might be due to the effect of fire. Most trees in the lower dbh classes were affected by forest fire at the burnt sites which reduced the total density and total basal area of the trees compared to the unburnt sites. The diversity of trees increased with increasing elevation. However, the diversity of saplings and seedlings reduced with increasing elevation.
文摘The manufacture of clean steel needs high performance carbon-free bricks for ladle lining.Based on long term application experiences of the prefab Al_(2)O_(3)-MgO blocks,unburnt Al_(2)O_(3)-MgO brick has been developed by pressing a mix of alumina,spinel and magnesia as major raw materials and Al_(2)O_(3)-MgO gel powder as binder.In addition to low open porosity and high strength,the unburnt Al_(2)O_(3)-MgO brick shows superior corrosion resistance and thermal shock resistance to the prefab block.Field trials in a 300t steel ladle have indicated the residual lining of unburnt Al_(2)O_(3)-MgO bricks showed smooth surface without large spalling and seldom steel infiltration,consequently longer service life than the prefab blocks.The reliable,unburnt Al_(2)O_(3)-MgO bricks have more advantages of high efficiency,energy-saving and eco-friendly production.It will be one of the best options for ladle lining in the manufacture of high-purity steel.
