CEMENT

This study investigates the properties of limestone calcined clay cement (LC3) with a water/cement ratio of 0.5 and cement/sand ratio of 1:2.75 produced using clay sourced from Uzebba, Nigeria. The kaolinitic Uzebba clay was calcined at 600°C, 700°C and 800°C to activate it's pozzolanic properties. Mortar cubes were cast and cured in lime water and by air. A total of 120 mortar cubes were prepared for compressive strength testing and water absorption test. For compressive test, 9 cubes were mixed and cured in lime water and air serving as the control, 27 cubes were mixed for LC 3 calcined at 600°C, 700°C and 800°C for 30% and 40% replacement and cured in lime water and by air. Additionally, this study utilized other tests like sieve analysis of fine aggregate, standard consistency test, setting time of cement and bleeding tests. The average compressive strength for 30% and 40% mortar cubes cured in lime water ranged from 9.44N/mm2 - 17.12N/mm2 and 7.47N/mm2 - 12.16N/mm2 respectively, while for 30% cured in air ranged from 5.70N/mm2 - 15.91N/mm2 For water absorption test, 12 cubes were mixed and cured in lime water to determine the amount of water absorbed by the cubes for the control and replacement.

Major contributions to the pollution in the atmosphere are Nitrogen dioxide (NO2) and
Sulphur dioxide (SO2) from cement factories as well as other industrial activities in Urban and Rural areas. The study area covers Ibese, Paplanto, Abeokuta, Ewekoro and
other rural areas as they play host to either cement factories or congested urban. This
research compared the amount of NO2 and SO2 released into the atmosphere at Ibese, Papalanto and Abeokuta. Sentinel 5P data for the study area was used to monitor these pollutants. Google earth engine editor was used to extract the pollutants over the study area. The duration considered was a 4-month interval within year 2019 to 2021 which was used to present 3 spatial maps per year resulting in a total of 9 maps for both pollutants. SO2 concentration ranged between -0.000161 to 0.0000782; -0.000206 to
0.000162; 0.000194 to 0.000228, for 2019, 2020 and 2021 respectively. NO2 concentration ranged between 0.0000459 to 0.0000846, 0.0000491 to 0.0000947, 0.0000565 to 0.000122 mol/m2 for 2019, 2020 and 2021 respectively. The spatial distribution for both pollutants were regrouped into 4 classes namely low, moderate, high and very high. Ibese fell once within the low class, seven times within the moderate class, five times each within the high and very high class respectively considering both the NO2 and SO2 maps. Papalanto fell twice within the low class, once within the moderate class, six times within the high class and eight times within the
very high class. Abeokuta fell six times within the moderate class and twelve times within the high class. The most dominant zone is the moderate zone followed by the high zone for SO2 and NO2 between 2019 and 2021. The frequency of occurrence of Papalanto and Ibese within the peak zone of SO2 and NO2 was very high when
compared to the frequency of occurrence of Abeokuta which never fell beyond the high
zone of either pollutant. This was attributed to the cement factory working nonstop located within Papalanto and Ibese.