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In this paper, the indoor air pollution was investigated inside an educational building which contains air pollutants with elevated concentrations. A field study was conducted in a naturally ventilated, single-faceted lecture’s hall to evaluate the indoor air quality (IAQ). Both air velocity and carbon dioxide (CO2) concentrations were measured at the respiratory area level to compare these values with ASHRAE standard (62.01-2019). The computational fluid dynamics (CFD) 3D model was utilized to predict the air velocity, and CO2 concentrations, and to validate the measured air concentrations. The measured results fairly agree with the numerical CFD data with a 6.2% difference between both values. This paper deals with experimental work to study the effect of the cross-section area, the number, and the height of the solar chimneys. The results showed that using solar chimneys improved the natural ventilation in the hall and minimized the CO2 concentrations. Additionally, using the chimney cross-section area of 0.25*0.25 m, 0.30*0.30 m, and 0.40*0.40 to 0.50*0.50 m can reduce the CO2 concentrations to (3%, 6.2%, 6.4%, and 6.7%, respectively). While using three chimneys instead of only one, the ventilation flow rate increased from 61 to 70.9%. The effect of the height of the chimney on the average of CO2 concentrations inside the hall was examined. The modeled height rates (1, 3, 5, and 7 m, respectively) were improved to 26%, 33.6%, and 48.7%, respectively.

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Lightweight concrete (LWC) is the most needed material to be used in many applications due to its low density, accepted compression strength, and high thermal properties. This paper study the effect of using lightweight concrete in structural elements using three experimental variables such as (admixtures content, cement content and w/c ratio). For twenty-five different mix trial with different admixtures was used. The slump loss, slump flow, compaction factor, compressive strength at the ages of 7, 14, 28, and 56 days and tensile strength at the age of 28 days were obtained. Based on the results the slump ranged from 70 to 140 mm. Moreover, the average slump loss was as same as the average slump loss for the normal concrete(NC). Further, the average compressive strength of the lightweight plain concrete mixtures fluctuated from 70 to 75% of the compressive strength of normal weight concrete and using admixture improved this ratio. By using mineral admixtures, the compressive strength improved to 90 to 95% of the normal concrete compressive strength.