زينب حسن عبد العباس الحسناوي

The objective of this paper is to calculate the really influential properties of concrete. These are the dynamic properties of sustainable concrete in situations at which metal waste can be found within its components. Growing the rate of pollution in the world, a fast decrease of original resources, the requirement for utilization of more areas of natural land and increase the price of the new available area are the reasons that make the researchers give great attention on the new concrete (green concrete) and destruction of unwanted material in the green mix. The concept of reuse aimed at sustainable structures was implemented within the current paper through consuming metal waste of cans and bottles caps in concrete. The waste materials were consumed in two modes; at 1st mode, it was applied in the role of fibers and mixed using 15% by weight of cement. On 2nd mode, it was applied as coarse aggregate with 25% replaced by volume. The procedure includes testing 4 concrete mixes. The estimated properties were the flexural and compressive strengths, besides modulus of elasticity. Adding bottle caps (waste materials fibers) in concrete led to enhancement in strengths. Use of walls of cans (waste materials fibers) in concrete reduced the strengths. While in case of compacted bottles caps plus pull-tab of cans (waste materials aggregate), concrete mechanical properties are a little below the reference mix. The dynamic properties of concrete containing these types of waste under impact load were determined. As known, the dynamic properties are so helpful in the strategy that deal with civil constructions put in danger of impact loads like runways, gas explosions, etc. CEB-FIP (2010) code provides wide-ranging formulas to predict the strain change of concrete. The dynamic properties determined by this code with consideration strain level between (10-2-100). In this range, dynamic loads in the civil constructions at level of quasi-static strain were predicted.

The desalination of brackish water is one of the common issues in the world and spiral wound membrane is mostly used in desalination systems in home and industrial level, in this study a spiral wound brackish water membrane element were used to study the reverse osmosis system practically with the effect of multiple operational parameters and by creating Matlab Simulink modeling to analyze the RO system performance depending on concentration polarization theory then compare both results. The parameters that studied were flow rate range (0.6, 1, 1.3, 1.6, and 2 cm 3 /s), concentration (100, 200, 300, 400 and 500 ppm), and temperature (15, 25 and 35 °C), of the feed and mass transfer coefficient for the permeate water, the salts that used (CaCl 2 and KCl) and by the concentration polarization (a phenomenon of accumulation of solute) the salts will tangle up at the surface of the membrane and affect membrane efficiency. The results indicated that the membrane operation is response sensitively to variations in feed temperature. The modeling results indicated that the major effect on the membrane parameters is the feed temperature and concentration of the salt.

In this investigation, the influence of using waste office paper fibers (WOPF) on the behavior of drying shrinkage in cement mortar have been presented. Cement mortar specimens size of (25×25×285) mm, and a length change measuring apparatus including a dial gauge capable of measuring the length accurately to ±0.002 mm have been used to study free drying shrinkage of cement mortar according to ASTM C596 – 01 method. The workability of cement mortar reinforced with WOPF was assessed by using flow table test method. WOPF was added to cement mortar in five ratios (0.2%,0.4%,0.6%,0.8%,1%) by weight of cement with two categories: In first one WOPF added after being soaked in water for 24 hours. While in second one WOPF added after being soaked in cooking oil for 48 hours. The total mixes were 10 in addition to the reference mix (the 11th mix) which made without WOPF. The results of the study indicated that the increase in WOPF ratio lead to reduce in workability. In first category, when WOPF ratio increased to 0.4%, the flow percent still within 110±5%, and when WOPF ratio increased to 0.6% and above the flow percent clearly reduced. While in second category, when WOPF added, the flow percent dropped obviously for all ratios. Drying shrinkage percent increased when WOPF was added to mixes compared with reference mix for all ratios used in both categories except the fifth ratio (i.e. WOPF 1%) in which the drying shrinkage percent decreased at age of drying 11, 18, 25 days for first category and at age of 18 and 25 days for second category. Drying shrinkage percent of mixes have equal ratio of WOPF in the both categories had the same tendency in variation with time. The loss of weight percent variation for all the mixes is approximately linear. The loss of weight percent of category I more than that of category II.

In the current study attention was focused on effects of using wastes of plastic and glass of juices and soft drink bottles in concrete, and the optimum percent's of the wastes were detected giving the best properties of concrete. Total number of concrete mixes was (12), which have different wastes additions details. These mixes included: three mixes have plastic fibers (1, 2, 3)% by cement weight, three mixes have glass with ratios of (10, 15, 20)% as a replacement of sand volume, three mixes have pieces of plastic bottle caps with ratios of (15, 20, 25)% as a replacement of gravel volume. The mix that has the optimum properties in these three groups, was selected to merge these types of wastes in one mix. Therefore, two additional mixes were prepared; one mix contains addition of 2% plastic fibers and 15% glass; and the other mix contains 20% plastic bottle caps and 15% glass, in addition to the reference mix without any waste additions. The achieved tests comprise; compressive strength, modulus of elasticity, flexural strength, ultrasonic pulse velocity, density, absorption and fire resistance. Tests results give good indications about using these waste in concrete; when two types of wastes are added to the mixes (plastic fiber with glass C11 or pieces of bottle caps and glass C12) the compressive strength is improved noticeably, the residual compressive strength is about (75% and 83%) with total ratio of wastes about 35% at age of 7 and 28 days, respectively, in mix C12, and (76 .7% and 70.5%) with total ratio of wastes about 17% at age of 7 and28 days, respectively, in mix C11.

One of environmental pollution and global warming sources is cement industrials. In line to diminish the effects of cement industrial activities on environment, wastes are used in cement mortar as a partial replacement of cement weight throughout the present study. These wastes comprise poultry egg shell which is wealthy in calcium and glass of bottles of juices and soft drink which has high content of silica. Both types of wastes were grinded carefully and passed sieve No. 200 ( 75µm opening size) to produce egg shell powder (ESP) and milled glass (MG). Cement was substituted by (5%, 7.5%, and 10% ESP), and (10% MG). These ratios of replacement was evaluated individually and in groups by compressive strength test at age of 28 days and drying shrinkage test at ages of 4, 11, 18, 25, and 60 days of drying. Results of tests indicated that compressive strength and drying shrinkage have the same trend when the replacement ratios of ESP used individually in mortar mixes. The higher results were recorded with ratios of 5% and 7.5%. While, compressive strength increased when 10% of MG was used as a partial replacement of cement, and drying shrinkage decreased at ages 11, 18, and 25 days of drying. The combination of MG and ESP in one mix, decrease compressive strength in all percent of addition. However the gathering of MG to 5% of ESP, and MG to 7.5% of ESP decrease drying shrinkage at all age of testing when compared it with the reference mix.

In this study, the impact of the use of Gum Arabic at low temperatures on concrete properties have been scrutinized. Gum Arabic was used in liquid state. The dosage of Gum Arabic was specified by using slump test. Low temperatures ranged between 4-10ºC, which represent mostly term winter temperatures in the central and southern regions in Iraq. The properties of concrete specimens were evaluated by measuring compressive strength, flexural strength, splitting tensile strength, absorption percent, density, and ultrasonic pulse velocity. The using of Gum Arabic in liquid state in concrete mixes improved compressive strength, flexural strength, splitting tensile strength, decreased segregation, increased the absorption percent and decreased the density of concrete and ultrasonic pulse velocity. The properties of fresh and hardened concrete with Gum Arabic were not evidently affected by low temperatures. Low temperatures deferred the hardening of concrete with Gum Arabic without a shrinkage in strength at the age 28 days although the absence of a curing process for 72 hours.