Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : impact resistance

Performance of Powdered Polymerized Concrete at Elevated Temperatures

Dina Mukheef Hamza

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 932-950

In the domain of concrete modification by using polymers, the present study, focused on the use of Carboxy-Methyl Cellulose (CMC) as a water-soluble polymer and investigate its effects on the behavior of concrete. The study include two issues, the first one is the effect of polymer adding method on mechanical properties of concrete such as compressive strength, tensile strength and modulus of elasticity in additional to impact resistance and the second is the effect of graded temperature on these properties. The polymer/cement ratio used herein is 3%, this ratio never used before in the previous researches on many types of water soluble powder polymers.
Three concrete batches were prepared, the first is the reference one as a normal concrete (NOR), the second is a polymerized concrete (POL1) where the polymer added as a latex, and the last also as a polymerized concrete (POL2) but the polymer added as a powder.Each batch contains twelve cubic specimens (100x100x100)mm for compressive strength test, three cubes for each level of temperature, eight cylindrical specimens (150x300)mm for splitting tensile strength test, two cylinders for each level of temperature, and four paneled specimens (450x450x50)mm for impact resistance test, one panel for each level of temperature.
It can be considered from the results that when the polymer CMC used herein added as a latex will give better strength behavior in polymerized concrete than the one which added as a powder by about 28.86% in compressive strength, 19% in splitting tensile strength, very high percent in modulus of elasticity and 16.66% in impact resistance. On the other hand, it is found that the temperature level of 200°C will affect the behavior of polymerized concrete and that contrast with the behavior of normal concrete while in temperature levels 400°C and 600°C the effects on polymerized concrete will be more slightly and more clearly on normal concrete.

Using Propylene–Ethylene Grid to Improve the Production of Precast Concret Slabs

Zainab Abdulrdha Thweny

Engineering and Technology Journal, 2013, Volume 31, Issue 4, Pages 741-751

The precast concrete roofing slab produced from the local factory were below the Iraqi standard requirement (NO 1107-1988).
This study has been made to improve the production of precast concrete slabs by using(propylene – ethylene copolymer grid )which is a waste material produced from the base of polymer boxes .
The depended mix of the precast concrete slab in the local factory did not use the correct proportion ,tested mixes were redesigned and prepared to achieve the limited requirements . Propylene – ethylene copolymer grid was used to have better results, less costs, with protection of the environment from pollution ,where there is difficulty to remove it even when it is fully exposed to severe weather conditions .the manufactured slabs had dimensions of (800×800×40)mm and testing program extended to 60 days of age and comprised ,breaking loads, water absorption ,and impact resistance of concrete. The total number of manufactured samples was (55 slabs).
The test results indicated that the weigh ted mix proportions ((1:1.5:2.45) cement :sand : gravel ) with w/c=0.41 , superplasticizer(0.75 liter/100 kg of cement )and propylene –ethylene copolymer grid with a dimension (600×600)mm enhances the mechanical properties of concrete . It increased the breaking load by 81 % compared to ordinary production. while the impact resistance increased to 26 blows compared to 3 blows for the ordinary production. However, the polymer grid decreased the width and depth of cracks and maintained the integrity of the slabs after failure .

Studying Some Of Mechanical properties Of (sawdust/Un Saturated Polyester) Composite in salt solution

Sanaa A. A. Hafad

Engineering and Technology Journal, 2010, Volume 28, Issue 16, Pages 5238-5245

Commercial sawdust is the most common wood filler used for polyster
thermosetting and is produced from graduated particles of different sizes which has in general has a lower aspect ratio than wood and other natural fibers. Wood additives include a mixture of sawdust and short chopped fibers. To study how characteristics of fibers and sawdust influence the mechanical properties of unsaturated polyester composites .Investigations were made by studying the effects of different volumetric fractions from sawdust and fiber fillers (up to limit
of 1.4mm), then these results were compared with the properties of sawdust –fiber filled composites immersed for different periods in a salt solution of (2 N) . wood volume fractions {(20, 30, 50) vf %} selected to be added for un saturated polyester were studied which gave improvement in their selected studied mechanical properties for all reinforced composites -(only impact is decreased)- and particularly at higher values of volume fractions ,were hardness showed an improvement by (15% ) , compressive strength gave obvious Improvement by
(38% ) ,while impact resistance decreased by (16%) with the reinforcement of (50 vf %) sawdust . The above values were reduced when the items were immersed in asalt solution for (60days).