In General, original reactive powder concrete (RPC) consists of a superplasticized cement mixture with silica fumes, steel fiber and ground fine sand (150-600 ىm). The main purpose of the present work is to produce and study some mechanical properties of lightweight reactive powder concrete using a superplasticized cement mixture with high reactivity metakaolin (HRM) instead of silica fume, steel fiber (with different ratios ) with ground fine sand (150-600 ىm) and light weight material called (Perlite ) also with different ratios .This investigation was carried out using several tests, these tests were compressive strength, modulus of rupture, modulus of elasticity, density and absorption, and performed for specimens at ages of 3, 7, 28 days, respectively. The tests results were compared with a reference mix. The experimental results shows that , with different ages, (for constant Perlit ratio for 0% to 10% as additional cementtitious materials) addition of 1% steel fiber will improve about (8.3%-10% , 3.2%-11%and 0.25%- 8%) for compressive strength , modulus of rupture, and modulus of elasticity respectively, and increase density, absorption about (0.8%-1.8%,4.5%-8.2%) respectively. Also an increase of steel fiber ratio to 2% will improve about (16.5%-20.3%, 9.0%-17%, and 1.7%-11.5%) for compressive strength , modulus of rupture and modulus of elasticity respectively, and increase density, absorption about (1.7%-2.3% , 7.3%-8.3%) respectively. For same steel fiber ratio about 0% to 2%, increasing Perlite ratio to 2.5% will decrease about (17.3%-18.8%, 9.5%-15.5%, 4.4%-16.6%, and 4.98% - 6.9%) for compressive strength, modulus of rupture, modulus of elasticity and density respectively and increase absorption to about (55.5% - 66.5%). Increasing the ratio to 5% will also make a decrease of about (36%-36.77%, 33.7%-37%, 16.5%- 21.88%and 15.91%-19.74%) for compressive strength, modulus of rupture, modulus of elasticity and density respectively and increase absorption for about (106%- 110.5%) . Increasing the ratio to 10% will also decrease about (45.98%-47.2%, 46.5-54.2%, 30.6%- 35.57%and 19.4%-23.36%) for compressive strength, modulus of rupture, modulus of elasticity and density respectively and increase absorption about(183%- 192.6%). To produce structural lightweight concrete, the tests results show that the optimum steel fiber is 1% by volume and optimum Perlite ratio is 2.5% by weight of cement as additional materials.
This investigation provides experimental results and nonlinear analysis by using finite element model of thick hollow core slab made from recycled lightweight material. Four hollow core slabs specimens were cast and tested in this investigation with dimensions (1200mm length, 450mm width and 250mm thickness). The crushed clay brick was used as a coarse aggregate instead of gravel. The iron powder waste and silica fume were used in order to increase the compressive strength of concrete. The techniques reduction hollow length and use shear reinforcement were used to improve shear strength and avoid shear failure. The specimens were tested by applying two-line load up to failure. The experimental results were showed these techniques were resisted the shear failure significantly and works to change failure mode from shear to flexural failure. Finite element computer software program (ANSYS) was used to analysis hollow core slabs specimens and compare the experimental results with the theoretical results. Good agreement have been obtained between experimental and numerical results.
Some mechanical properties of mortar (compressive strength and hardness) with sawdust replacement of sand were investigated. Cubes of 50 mm × 50 mm were prepared, the compressive strength tests were done for a replacement levels ranging (5, 10, 15, 25, 50, 75) % by volume a reference mix were also prepared for comparison this test was done after 7, 14, and 28 days while hardness test were done after 28 day for a replacement levels (0, 5, 10, 15, 25) % by volume. Result showed that the compressive strength of the specimen were decreased with higher sawdust content, hardness values were decreased slightly in the replacement levels 0, 5, 10 % while the values began to decrease noticeably in the replacement levels 15 and 25 % the hardness values were (59, 57.5, 56, 47.77 , 45.2) N/mm2 respectively A cost analysis was done, this analysis was based on a unit of mortar (1.0 m3) made from conventional materials and a modified concrete made by substituting materials with sand using sawdust
This research work includes production of polymer modified polystyrene concrete and studies the mechanical properties. Several proportions of raw materials were used to produce this type of concrete. This study is intended to improve the mechanical properties of light weight polystyrene concrete using styrene butadiene rubber(SBR) with rate of (5,10,15and20)% of cement weight. Compressive strength, flexural strength, impact strength and dry density tests were made on more than 150 specimen at age of 28 days. The results show that the addition of (SBR) with range of (5-20)%of cement weight is improve the flexural strength with range (3.74-18)%, and improve the impact strength with range (39-163)%. Also the results show that it is possible to produce polystyrene concrete with density (1680,1433 and 1147) kg/m3 replacing light weight Polystyrene aggregate with volume fraction (30,50 and70)%of sand.