Engineering and Technology Journal

In many road construction projects, if weak soils exist, stabilization and improvement of their properties is necessary. The stabilization process aims at increasing the soil strength and reducing its permeability and compressibility. An experimental program was undertaken to study the effect of engineering properties of kaolin clayey soils ((the kaolin was supplied by the General Company of Geological Survey and Mining which originally obtains from Al-Dewiekhla near Aukashat district in the west of Iraq)) when blended with lime (L) and Silica Fume (SF). A series of laboratory experiments have been implemented for varieties of samples: 2.5%, 5.0%, 7.5% and 10.0% for (Lime) and 2.0%, 4.0% and 6.0% for(Silica Fume). These experiments are: consistency limits test, specific gravity test, compaction test, unconfined compression test and California bearing ratio test. For each test, the optimal quantity of Lime (L) and the optimal percentage of Lime Silica Fume (LSF) combination were determined. The results revealed that: the optimal percentage of LSF combination was attained at a (2.5%L+6.0%SF), which served as control in this study. This optimal percentage: decrease the liquid limit, plasticity index, specific gravity and maximum dry density; and raise the optimum moisture content, unconfined compressive strength and California bearing ratio. These results showed also, that the combination of LSF stabilization at (2.5% L+6.0% SF) is better than the optimal one which achieved by Lime alone: 2.5%L for plasticity index, 10.0%L for specific gravity, maximum dry density and optimum moisture content, 5.0%L for unconfined compression stress and 7.5%forCaliforniabearingratio. All of these results indicated that the engineering properties of clayey soils can be enhanced, by blending Lime and Silica Fume together.

Industrial wastewaters from local state textile industry (Al-Khadimia Textile Co.) as well as aqueous prepared solutions of color dyes were subjected to simple physico-chemical treatment. The effect of pollutants concentrations, magnesia and other coagulants doses, filtration rate and the overall run time on the water quality were studied in detail.
The treatment involves the addition of either magnesia or lime-water suspensions (combined with CPE) in various doses, 0.1-1.0 g/l to the wastewater and colored samples, to study the effect of varying doses on the treatment efficiency. The optimum values of MgO doses were found to be 0.2-0.4 g/l for synthetic colored. Doses of 0.05-0.2 g/l were the best for industrial wastewater. The removal efficiency of all the pollutants in the different samples increases to more than 95% by increasing the pH values to the range of 9.5 to 10 with MgO coagulant and pH of 11.5 to 12 with CaO coagulant.
In the jar experiments the rotation speed, N, of 120-140 rpm, for two minutes was the most favorable speed of coagulation mixing for industrial waters. For flocculation, the mixing speed of 35-40 rpm, (G of 40-45 s-1) gave the best removal efficiencies with 20-30 min detention time.
At the best operating conditions of the pilot plant, the removal efficiencies of Turbidity, TSS, and color were 97-99%, 94-96%, 94-95%. The TDS removal efficiency was of 39% for Al-Khadimia wastewater.

Sawdust concrete has some shortcomings due to the harmful effects of some organic soluble components existing in the sawdust which affects setting and strength of sawdust concrete. Also, volume changes of sawdust as an aggregate due to variation of moisture content, cause large volume changes in the sawdust concrete. In this work, sawdust was treated before using as an aggregate for making sawdust concrete. The treatment included boiling the sawdust in water containing hydrated lime in order to dissolve all soluble organic components. To reduce water absorption of sawdust, it was dried and treated with waterproofing material. Two types of waterproofing materials were used (cutback asphalt and classic varnish). The properties of sawdust concrete were highly improved using pretreated sawdust. The increase of compressive strength was up to 50% for moderate sawdust ratios. Flexural strength is also increased, water absorption and thermal conductivity were highly reduced, while the basic advantages of sawdust concrete such as lightness of weight, sawability and nailability were not affected.

Recently, many attempts were made to use metal fiber reinforcements to
improve some soil properties. In this research, the effects of fibers on the
compaction and mechanical properties of cement and lime stabilized soils (silty
and clayey soils respectively) were studied. Variables such as stabilizer (cement
and lime) content, amount and type of metal fibers were studied. Results indicated
that the addition of fibers lead to increase in the maximum dry unit weight. On the
other hand, a maximum values of unconfined and tensile strength were obtained
with the addition of 0.5 % short fiber (FS) and 1.5 % long fiber (FL) respectively.
During the flexural test a brittle manner failure was observed for the unreinforced
samples and samples prepared with little amount of fibers 0.5%. Finally, the
addition of fibers increases the fracture energy of cement stabilized silty soil and
lime stabilized clayey soil.

The single component and multi-component hydroxide precipitation and
adsorption were studied for different heavy metals namely Iron (III), Chromium
(III), Copper (II), Lead (II), Nickel (II), and Cadmium (II) from aqueous solutions.
By using the jar tester Magnesia (MgO) was used as a precipitator at different
doses and compared with other chemicals like lime (CaO) and caustic soda
(NaOH). The treatment involves the addition of either magnesia or lime-water
suspensions (combined with cationic polyelectrolyte, CPE) in various doses, 1.0 –
5.0 g/l for the metal samples to study the effect of varying doses on the treatment
efficiency. The results show that the percent removal of metal ions increases to
about 99 % with increasing the MgO dose to some limits. The optimum values of
MgO doses were found to be 1.5-3.0 g/l. The pH value ranges are 9.5 to 10 with
MgO precipitant and pH of 11.5 to 12 with CaO precipitant. In the jar experiment
the rotation speed, N, 180-200 rpm, (G of 460-480 s-1) of mixing for two minutes
was the most favorable speed of rapid mixing and the slow mixing speed of 15-30
rpm, G of (14-35 s-1), for twenty minutes gave the best results.At the best operating
conditions of the pilot plant, the removal efficiency of metal ions was more than
97% at doses of MgO (1.0-4.0 g/l).

Huge amounts of glass materials being applied in medical, pharmaceutical
and chemical aqueous solutions; this requires the study of chemical stability of glass at the exposed surfaces with these solutions where the leaching takes place. The leaching of the glass ions will transport these ions to the solutions stored in the glass containers; leading to changes in the chemical composition in the order of part per million that causes hazardous effect with time. The present work investigates the leaching chemical properties of the soda-lime Iraqi glass containers. The effect of the pH of contact solution and
annealing of glass on leaching rates is studied. Ionic leaching shows lower rate with PH of the solutions at the ‘safe zone’: (6>PH>8.5). Annealing increases the leaching rates and reduces of the chemical durability of glass. Increasing annealing time led to further increase the leaching rate. In addition, the increase in the exposed surface area also increases leaching rates.