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EVALUATION OF COAL WASTE ASH AND RICE HUSK ASH ON PROPERTIES OF PERVIOUS CONCRETE PAVEMENT G. Shafabakhsh and S. Ahmadi Abstract The use of pervious concrete has been significantly considered in recent years. This consideration is due to the properties of pervious concrete in relating to the environmental sustainability that is utilized in the effective management of the runoff from rainfall. Coal extraction and rice husk obtained from milling, produces wastes that have no application and followed by environmental pollution. The purpose of the current research, is to evaluate of the effects of coal waste ash (CWA) and rice husk ash (RHA) and to compare between the mechanical properties of pervious concrete pavement. Therefore, both of these wastes were burned and after that XRF testing it was observed that they both achieve Pozzolanic properties. In order to strengthen pozzolanic cement paste has been used CWA and RHA as a cement replacement in concrete mixtures. The results indicated that the addition of RHA and CWA improved the mechanical properties of pervious concrete, however the optimum percentage is dramatically varying. Among these, the effectiveness of CWA is more significant compared to RHA. By increasing the amount of CWA and RHA to the optimum level, the permeability of the pervious concrete will decrease simultaneously. Meanwhile, after the optimum level, it will be reversed. Keywords Pervious Concrete Pavement, Mechanical Properties, Rice Husk Ash, Coal Waste Ash چکیده استفاده از بتن متخلخل به طور قابل توجهي در چند سال اخير مورد توجه قرار گرفته است. اين توجه به دليل ويژگي هاي بتن متخلخل در رابطه با محيط زيست پايدار در مورد مديريت موثر رواناب ناشي از بارندگي مورد توجه مي باشد. استخراج زغال سنگ و پوسته برنج بدست آمده از شالیکوبی، پسماندهایی را تولید می کند که هیچ کاربردی نداشته و آلودگی محیط زیست را در پی دارد. هدف از این پژوهش بررسی اثر ضایعات زغال سنگ سوخته و خاکستر پوسته برنج و مقایسه بین این دو بر خصوصیات مکانیکی روسازی بتنی متخلخل می باشد. بنابراین در این مطالعه هر دوی این مواد پسماند سوزانده شده و بعد از انجام آزمایشاتXRF مشخص گردیدکه هر دو این مواد خاصیت پوزولانی پیدا می کنند. در مطالعه حاضر به منظور تقویت خمیر سیمان از پودر ضایعاتی زغال سنگ سوخته و خاکستر پوسته برنج به عنوان جایگزین بخشی از سیمان در ترکیبات بتن استفاده شده است. نتایج نشان می­دهد اضافه شدن پودر ضایعاتی زغال سنگ سوخته و خاکستر پوسته برنج سبب بهبود خصوصیات مکانیکی بتن متخلخل می شوند این در حالی است که محدوده درصد بهینه آنها متغیر می­باشد. در این بین اثر پودر ضایعاتی زغال سنگ سوخته بسیار چشمگیرتر از خاکستر پوسته برنج بوده است و از طرف دیگر با افزایش مقدار پودر ضایعاتی زغال سنگ سوخته وخاکستر پوسته برنج تا مقدار بهینه نفوذپذیری بتن متخلخل کاهش و در ادامه افزایش می یابد. منبع دانلود 29-2-8.pdf

Long Term Dry and Wet Effects on the Engineering Behavior of Subgrade Soil with High Amount of Soluble Salts using Low Cost Stabilizers Original Article, D74 Ibrahim S.F., Ibrahim M.S., Abd hak H. J. Civil Eng. Urban. 4(5): 492-500. 2014 ABSTRACT: The performance of pavements depends upon the quality of subgrades. A stable subgrade and properly draining pavement help to produce a long-lasting pavement. Subgrade soil provides support to the remainder of the pavement system. This study is performed to evaluate the effect of total soluble salts (T.S.S.) on the strength of subgrade soil brought from Al-Mahmodia city south of Baghdad. Chemical and physical test, carried out on the soil sample, indicate that, the soil is lean clay of (CL) group according to the Unified Soil Classification System (U.S.C.S.). The soil sample contains about (15.685%) by weight of (T.S.S.) content. Different stabilizers are added to the subgrade soil to study the influence of these stabilizers on (T.S.S.) and the strength of subgrade, the stabilizers are (5% lime, 2.5% calcium chloride, 6% kaolin, 6% Rice Husk Ash and 5% saw dust). California Bearing Ratio (CBR) test is determined for the natural soil and different stabilizers with different number of blow per layer (10, 25 and 56) for (4-days) soaking periods under (10 Ibs.) surcharge load. The number of blow per layer and (CBR) value, required to achieve (95%) relative modified proctor compaction are determined from the results of different number of blow (10, 25 and 56) and soaked for (4-days). The (CBR) value of the natural soil at 95% relative modified proctor increases by about (48%, 66.1%, 36.1% and 38%) for the (2.5% CaCl2, 5% lime, 6% RHA, 6% kaolin) respectively. While the CBR value of soil with the (5% saw dust) decreases to (29%). The (T.S.S) is reduced after the addition of the different stabilizers. Durability test (long term soaking) for the subgrade stabilized with (6% RHA) and compacted at 95% relative modified proctor is conducted, the results of soaking showed reduction in both (CBR) value and (T.S.S) with the time. Keywords: Strength, Rice husk ash, Total soluble salts, Durability, Calcium chloride منبع: [Hidden Content] دانلود: [Hidden Content].,%204%20(5)%20492-500,%202014.pdf J. Civil Eng. Urban., 4 (5) 492-500, 2014.pdf

Improvement of Clayey Soil Characteristics Using Rice Husk Ash Original Article, C3 Mohammed Y. Fattah, Falah H. Rahil, Kawther Y. H. Al-Soudany. Journal. Civil Eng. Urban. 3(1): 12-18. 2013 ABSTRACT: Rice husk ash (RHA) is a pozzolanic material that could be potentially used in soil stabilization, though it is moderately produced and readily available. When rice husk is burnt under controlled temperature, ash is produced and about 17%-25% of rice husk’s weight remains ash. This paper presents the results of experimental study carried out on three different soils improved with different percents of rice husk ash. Samples were brought from different sites of Iraq. The testing program conducted on the clayey soil samples mixed with different percentages of rice husk materials, included Atterberg limits, specific gravity, compressibility, unconfined compression test and consolidation test. It was found that the liquid limit of the three soils has been decreased by about (11 - 18) % with the addition of 9% RHA, while the plasticity index decreased by about (32 - 80) %. Treatment with rice husk showed a general reduction in the maximum dry unit weight with increase in the rice husk content to minimum values at 9% rice husk content. The optimum moisture content generally increased with increase in the RHA content. There is enormous increase in the unconfined compressive strength with increase in rice husk content for the soil to its maximum at RHA between (6 – 8) %. Keywords: Clayey soil, improvement, rice husk ash, strength. منبع: [Hidden Content] دانلود: [Hidden Content],%203(1)%2012-18.pdf JCEU-2013-C3, 3(1) 12-18.pdf