Abstract This research studies the effect of adding steel fiber in two percentage 0.5% and 1% by volume on plain structural lightweight concrete (SLWC) produced by using crushed bricks as coarse lightweight aggregates (LWA) in a lightweight concrete mix designed according to ACI committee 211-2-82 with mix proportion 1:1.12 :3.35 by volume .The wc equal to 0.5 and cement content 550 kgm3. Different tests where performed for fresh and hardened SLWC such slump test ,fresh and hardened unit weight ,compressive strength and two indirect tests of tensile strength (splitting tensile and flexural strength). The results demonstrated that the effect of addition of steel fiber was more pronounced on the tensile strength of SLWC than the compressive strength of such concrete .The maximum increase of compressive ,splitting tensile and flexural strengths at 28-days were 38.8,77.12 and 111.2 % in the SLWC containing 1% fiber. On the other hand the rate of strength gain between 3 and 28 days was constant on compressive strength of plain concrete and that containing steel fiber while this rate was clearly increase on tensile strength especially flexural strength.
Brick as a construction material can be considered one of the most common materials used for a very long time to construct buildings in iraq. The historic building represents one of the most important figures representing the rich history of iraq, which is built with bricks. Due to the aging of this type of building, a necessary improvement and retrofit need to occur. The paper investigates the ability to use different kinds of materials such as cfrp and srg to enhance the brick columns' structural capacity. From the results and discussions, it can be concluded that these materials are suitable to be used for this purpose with some limitations due to brick capacity itself.
Fresh and hardened properties of self-compacting concrete was experimentally examined by replacing different percentages of cement by soft clay powder, which resulting from crushing the wastes of clay bricks. Three percentages (5%, 10%, and 15%) of cement were replaced with clay powder to study their effect on the properties of cement mortar and concrete of Grade (C35) in both fresh and hardened states. It was found that development rates of the compressive and tensile strengths for the mortar between ages of 7 to 28 days, decreased with increasing the percentage of the clay powder. Compared to the mix without clay powder, it was found that replacing (5%) from the cement causes a significant increase in the workability of the self-compacting concrete and the properties of the resulting hardened concrete such as compressive strength, tensile strength, and modulus of elasticity. While using (10%) and (15%) of the clay powder causes a significant decrease in the workability of the fresh concrete and the properties of the hardened concrete compared to mix without clay powder.
To reduce using the brick as a unloaded walls in frame building by using concrete parts to preproduction walls and is assemble in working area , the suggested wall is consist of a double parts (1000x500x140)mm with 50mm insulating material and arrangement parts by roller bolts with building frame and covered by sheets as external finishing material, and used a gypsum layer of 3mm thickness as an internal finishing material, therefore, the total wall thickness is 200mm. The thermal behavior of that suggested wall was measured for 15 hour/day for one day in July month. in Baghdad climate region (33.2 N°). The researcher found that, the metal sheet which paint with thermal & plastic paints cover that suggestive wall is gave more energy saving when it compared with brick wall (240mm,120mm) and the saving value was increased when uses reeds stalks sheay 50mm (thickness) as an insulating material among the concrete wall instead of air gap.
In this paper three material with equal amount have been chosen to make a mixture, these materials are sand (passing sieve no. 1.18, porosity 0.41), activated carbon (passing sieve no. 4.75, porosity 0.51), crushed bricks (passing sieve no. 20, porosity 0.47), the mixture was used as a bio-filtering media , placed to a height of (1.15) m in a cylindrical filter with diameter of (300)mm and a height of (2)m which is designed and constructed from (PVC). The filter is equipped with three piezometers fixed at three point along the height of the cylindrical filter, in addition to three overflows at different height, and an outlet with control valve. On May 2010 the filter was operated with a synthetic wastewater similar to domestic sewage in order to determine the hydraulic and sanitary characteristics of the filter. Then the feeding of waste water was continued for 3 weeks in order to stimulate the growth of bio-film. On June 2010 the filter was operated with gray water to determine the change in filter characteristics after the bio-film growth, and to evaluate filter efficiency to treat this water for the purpose of reuse. The outcome of this work showed that the mixed media bio-filter, to a certain extent, is similar in hydraulic characteristics (pressure drop and hydraulic load) to granular activated carbon bio-filter, head loss at (1000) mm depth is (59%) of initial pressure, the growth of bio-film leads to increase in head loss by (43%), decrease in flow by (25|%), decrease in pressure by (16%). According to removal efficiency of pollutants, the results shows an efficient removal of BOD5 (86%), turbidity (96%), TDS (81%) at a retention time (60 minute).