This research presents an experimental program to study the effect of using angle shear connectors instead of the headed stud on the flexural behavior of composite beams under negative bending moment (NBM). Both the angle and headed stud shear connectors used in this study have the same cross-sectional area. Five composite beams were casted and tested using three-point load configuration to ensure the NBM effect. Different parameters were included in this study such as the type of shear connector, bond interaction (partial and complete bond interaction) and arrangement of angle shear connectors. Two proposals method were suggested for angle setting in this study to investigate the structural behavior of the composite section. It has been found that, in the case of single angle shear connectors, the ultimate strength decreased by 4.12% compared with samples with the headed stud shear connectors. The direction of the angle setting has been shown to affect the flexural behavior of the composite section.

The punching shear strength of reinforced concrete (RC) flat slab is the main concern in the structural behavior. This study presents a strengthening technique for improving punching shear resistance in RC two-way flat slabs using RC column capital. Two sizes of column capital were used (600 × 600 and 800 × 800 mm), and the influence of column capital on the behaviours of two-way solid slabs under concentric and biaxial loading thus investigated. Six specimens were tested, with two slabs as reference specimens with concentric and biaxial loading, and four slabs with added column capital. The dimensions of the slabs were 1,600 × 1,600 × 100 mm, while the column dimensions were 200 × 200 mm. The eccentricity of the biaxially loaded slab was set to 150 mm in both directions. The results showed a considerable increase in punching shear capacity for flat slabs using column capital; further, as the column capital increased, the punching strength of the slab also increased.

The effect of retarding admixture on the fresh and hardened behaviour of different types of cement mortars and pastes when using a retarding admixture was investigated in this study. The types of cement used are; White cement (WhC), Ordinary Portland cement (OPC) and Sulphate Resistant Portland cement (SRC). Different cement mortar and paste mixes were cast, for this purpose, with and without the admixture. Initial and final setting times, compressive strength, length change, absorption and density for these mixes were examined at the curing ages of 3,7,28,45 days. The results showed that the addition of retarding admixture delayed the setting time significantly of WhC paste. The retarding admixture has a positive effect on the compressive strength of the mortar specimens for all types of cement used. regarding the length change test, the admixture was found to reduce the initial expansion for all types of cement at all ages. The results also showed an increase in the density and decrease in water absorption, especially at the later ages for all types of cement.  Among all cement types used, WhC was noticeably the most affected type by using the retarding admixture compared to other types of cement used.