Voided slabs are reinforced concrete slabs in which voids allow to reduce the amount of concrete. The bubbled deck slab is a new and sustainable biaxial floor system to be used as a self-supporting concrete floor. The use of voided slabs leads to decrease the consumption of materials and improve the insulation properties for enhancing the objectives of sustainability. This study presents an investigation into the flexural behavior of sustainable Reactive Powder Concrete RPC bubbled slab flooring elements. Six one-way slabs were cast and tested up to the failure. The adopted variables in this study are: the volumetric ratio of steel fibers, type of slab; bubbled or solid, placing of reinforcement and thickness of slab. The effect of each variable on the ultimate load, deflection and strain has been discussed. The results show that increasing the percent of steel fibers from 1% to 2% in solid and bubbled slabs decreases the deflection by (18.75%) and (50%) respectively. As well as, the deflection increases by (41%) for bubbled slab compared to the solid slab. The slabs reinforced with top and bottom steel meshes show less deflection than slabs reinforced by only bottom steel mesh.

No abstract

This investigation provides an experimental study about structural behavior of reinforced hollow core slab (HCS) by using recycled lightweight material. Six hollow core slab specimens were casted with dimensions 1200mm length, 450mm width and different thickness (200mm, 250mm and 325mm). The shear reinforcement was used for each thickness to resist the shear failure that occur in thick hollow core slab. The Recycled materials were crushed clay brick and iron powder waste. The crushed clay brick was used as a coarse aggregate instead of gravel to a get lightweight concrete. The hollow core slab specimens were tested with age 28-day. The test was done by applied two line load up to failure. The experimental results showed an increase in the shear strength up to 50% and decrease in the maximum deflection up to 50% with increasing thickness specimen. Also the experimental results showed an increase in the shear strength up to 50% and increase in the maximum deflection up to 50% with using shear reinforcement compare with hollow core slab specimens without shear reinforcement. From the experimental results of this investigation can be avoid the shear failure and change the mode of failure from the shear to flexural failure.

Megaprojects are classified within large investment projects which have a long term impact on the economy, the environment, and the society. Megaprojects are huge development projects such as railways, motorways, dams, power plants, airports and processing projects. Numbers of megaprojects have been constructed and some of them are in the construction process or in the planning level, therefore, this research focused on these megaprojects to investigate the factors that could influence them in Iraq. Accordingly, the practical study consisted of quality data collections through interviews and quantitative data collections through questionnaire. The interviews have been done with six (6) experts in privet companies. The questionnaire survey has been conducted in government institutes. 85 questionnaire forms have been distributed; only 81 forms are collected. The results of this research project revealed that less than half of the Megaprojects in Iraq are unsuccessful. However, there are numbers of reasons which may causing the failure in projects, such as insufficient and weaknesses in financial, quality and management abilities. Accordingly, there are some factors that influence the success of the megaproject in Iraq, such as increasing the confidence in local government, clarity of project vision and goal and compatibility with the long-term government plan.

This research paper focused on the experimental study about shear behavior of reinforced concrete thick hollow core slab. The reduction hollow length technique was used to resist the shear failure that occurred in the thick hollow core slab. The three hollows were used in tested slabs. The effect of reduction in the length of hollow in the shear region as well as the sides hollow was considered in the shear behavior of the tested hollow core slab. The recyclable material was used to a get of lightweight concrete, where the crushed clay brick was used as a coarse aggregate instead of the gravel. The test was done by applying two line load. The specimens were tested up to failure. The experimental results showed an increase in the shear strength up to 109.52% and an increase in the deflection up to 24% compared with the hollow core slab specimen that all hollow core is accessible. From the experimental result of this investigation can avoid the shear failure subsequently the load devolves from the shear region to the flexural region with change the mode of failure from shear failure to flexural-shear failure.