Wyniki wyszukiwania - BazTech

1

Ground water quality in Wadi Shati (Libya): Physicochemical analysis and environmental implications

Ahmad Omar Asad, Gazzaz Nabeel M., Alshebani Amnah Khair

Journal of Water and Land Development

|

2022

|

no. 53

128--137

EN

This study aimed at evaluating water quality of groundwater wells (GWWs) in Wadi Shati, Libya, and assessing its suitability for drinking. Water samples were collected from 17 GWWs and subjected to laboratory testing for 24 physical and chemical water quality parameters (WQPs). Analysis uncovered that the recorded values of 11 WQPs were consistent with the Libyan drinking water quality standard (DWQS). These parameters were pH, temperature (T), acidity, alkalinity, electrical conductivity (EC), sodium, potassium, calcium, magnesium, zinc, and cadmium. However, values of colour and turbidity exceeded the maximum levels set by the Libyan DWQS at five out of the 17 study wells. Likewise, concentrations of chloride (Cl-), sulphate (SO4 2-), and ammonia (NH3) violated the local DWQS in three locations, each. Additionally, concentrations of phosphate (PO43-), iron, manganese, chromium, and nickel exceeded their maximum allowable concentrations according to the Libyan DWQS. The levels of these five parameters are alarming. Overall, the 17 studied GWWs suffer from varying levels of pollution that, mostly, arise from domestic and agricultural sources, e.g., septic tank seepage and agricultural drainage of agro-chemicals like fertilisers and pesticides. The results of this study emphasise that routine monitoring of groundwater resources plays a vital role in their sustainable management and stresses that water quality data are critical for characterisation of pollution, if any, and for protection of human health and ecosystem safety. Our results serve as guideline for sustainable management of water quality in the Wadi Shati District.

2

The strength behaviour of transitional group A-2-7 soil stabilized with fly ash and lime powder

Ahmad Omar Asad

Archives of Mining Sciences

|

2021

|

Vol. 66, no. 4

511--522

EN

Recent works aimed to investigate geotechnical properties of Transitional Group A-2-7 (TGA-2-7) soil affected by the use of hydrated lime and fly ash class F, by-products from quarries and a cement factory in Jordan, to compensate for the gap in the granular distribution. Host soil was exposed to various proportions of fly ash and lime powder. The blended specimens were subjected to different tests related to index properties, including Atterberg limits, compaction properties and California bearing ratio. The results demonstrate that 2% fly ash led to a reduction in the plasticity index from 19% to 10%, while lime powder reduced it from 19% to 13%. A sufficient improvement of maximum dry density was observed at 20% lime addition and increased from 15.11 kN/m3 to 16.29 kN/m3. California bearing ratio that measures the strength soil linearly increased up to 10% induced by 20% lime addition.

3

The use of sand columns in the reinforcement of weak layers in road engineering

Ayyad Sami Mohammed, Ahmad Omar Asad

Archives of Civil Engineering

|

2021

|

Vol. 67, nr 1

527--538

EN

It is an established fact that when roads are planned and constructed, consideration needs to be given to ensuring the strength of the road surface. It is, however, also the case that when an existing road is being rebuilt or is under maintenance, its base may need to be fortified to increase the road’s vehicle-carrying capacity. The base may, for example, contain a high proportion of weak soil that would be difficult, time-consuming, and costly to remove. This paper aims to investigate the efficacy of using sand-filled piles to reduce road deformation. Experiments conducted on sponge samples confirm that there is a relationship between the total area of sand-filled piles and relative reduction in deformation. It finds that the relationship is non-linear, but that the relationship can be made linear by adjusting the area of sand-filled piles. When the area of sand-filled piles increases from 7.8% to 19.4%, the deformation module can change by up to 100%. Relative reduction in deformation can change from 14% to 45.5% when the area of sand-filled piles increases from 7.8% to 11.7%. The maximum reduction in deformation - 92.4% - occurs when the area of sand-filled piles exceeds 19.5%. Changing the loads borne also affects the deformation module. This paper found that when there was a 10 to 15kg load, and the number of sandfilled piles was increased, there was a change in the deformation module by 380-470%. When there was only a 5kg load on the sample, and the number of sand-filled piles was increased, there was a change in the deformation module by up to 1217%.

4

Secondary treated wastewater as a concrete component and its impact on the basic strength properties of the material

Ahmad Omar Asad, Ayyad Sami Mohammed

Archives of Civil Engineering

|

2021

|

Vol. 67, nr 1

571--583

EN

In Jordan, the unprecedented proliferation of building projects is anticipated to increase the potable water demand in the construction manufacturing. In the present work, secondary treated wastewater (STW) and potable water (PW) were used in the production of concrete mixes, which were subjected to testing after 3 to 28 days of curing to determine how the, mechanical properties of concrete was affected by the addition of secondary treated wastewater in various proportions (25-100%). Results indicated that the use of 25% and 75% of secondary treated wastewater in concrete production increased the compressive strength to 39 MPa after 28 days of curing. A more noticeable increment was recorded in tensile strength, which was double that achieved with the standard design. Overall, the compressive strength increased by 21.95% when secondary treated wastewater was used, while the expenditure related to water usage was halved. Furthermore, there was consistency between the results obtained from scaling up to actual ready-mix concrete production and the results of the empirical work.