This paper presents the results of structural reliability analysis of a structural element (beam) in building using First-order reliability method (FORM) to ascertain the level of safety. The natural stone (NS) which is the by-product of Precambrian deposits of the Bida trough was used as coarse aggregate: unwashed and washed aggregates were used. A total of 80 concrete cubes of 150 mm × 150 mm × 150 mm were cast and used for this study, sensitivity analysis was conducted by varying the span, depth, effective depth, area of shear reinforcement and dead load of the beam in bending. The result of the sensitivity analysis revealed that the beam utilising unwashed and washed NS are both structurally safe at a span of 3000 mm with probabilities of failure of 9.20 × 10–5 and 2.06 × 10–8 and both safe at a depth of 600 mm with probabilities of failure of 4.19 × 10–4 and 2.602 × 10–4, respectively, in bending.

Concrete is an assemblage of Cement, aggregates and water, the most frequently used fine aggregate for concrete production is sand sourced from river banks. The continuous exploitation of available granite conventionally used as coarse aggregate in concrete production coupled with rapid infrastructural development has resulted in its scarcity and often high cost. The suitability of utilising Palm Kernel Shell (PKS) as partial replacement for coarse aggregate in concrete production was examined in this paper. Preliminary tests were conducted on all aggregates to determine their suitability for concrete production. Concrete with 5, 10, 15, 20 and 25% PKS-coarse aggregate content was cast with a mix ratio of 1:2:4. The freshly prepared Palm Kernel Shell Concrete (PKSC) was cast in moulds measuring 150 x 150 x 150mm and cured using ponding method. The Compressive strength result shows that an increase in the PKS content results in a decrease in compressive strength of concrete. Linear regression models for the slump and compressive strength of the PKSC were developed and found to be sufficient in predicting the compressive strengths with R2 values of 96% and 92 % respectively.

Concrete is an assemblage of Cement, aggregates and water. The most frequently used fine aggregate for concrete production is sand sourced from river banks. The continuous use of this river sand as a result of rapid infrastructural development has resulted in its scarcity and often high cost. This paper examines the suitability of using quarry dust (QD) as partial replacement for fine aggregate in concrete production. Preliminary test (specific gravity) was conducted on the aggregates to determine their suitability for concrete production. Concrete with 5, 10, 15, 20 and 25% QD – Fine aggregate content was cast with a mix ratio of 1:2:4. The freshly prepared Quarry Dust Concrete (QDC) was cast in moulds measuring 150 x 150 x 150mm and cured using ponding method. The Compressive strength result shows that replacement of fine aggregate with QD leads to a general increase in compressive strength of concrete. Statistical package for the Social Sciences (SPSS) version 21 was utilised to develop the linear regression models for the 7 and 28 days compressive strength of the QDC. The developed models were found to be sufficient in predicting the 7 and 28 days compressive strengths with R2 values of 98.9% and 95.2 % respectively.