The purpose of this research is to produce a modified SCC that involves the incorporation of expanded polystyrene (EPS) and waste of plastic type (PET). The goal is to minimize the weight of the material while simultaneously improving its brittleness and reducing the environmental impact. The study focuses on two methods for reducing the weight of structural elements by using EPS beads, which create voids through concrete, and the second method is making a hollow through the element. This study included designing and investigating four concrete beams under concentrated static load. The parameters were hollow position and material types. The results showed that the offsetting hollow from the center of the beam enhanced the ductility index by 10% and increased the load capacity by 10%. Adding EPS beads reduce the concrete density by 11.5% and load capacity by 22%. Toughness was improved by using plastic fiber due to the mechanism of crack bridging. The crack pattern had been changed due to the utilization of waste material, and enhancement was observed through experimental tests by making smooth cracks and changing the probability of sudden failure when using GFRP rebars. It was found that the optimal quantity of EPS was 2 kg to produce SCC in accordance with code requirements. No debonding or slip was observed during monitoring, as evidenced by the absence of spalling or cracking around the reinforcement.
At the last period, the problems of the pre-cast concrete units have been increased rapidly due to its unconformity to the adopted specifications with regards to sulphate content. The high content of sulphate in Iraqi fine aggregate in many aggregate quarries, which are out of the Iraqi standard specification limits, causes many difficulties for most pre-cast concrete units Factories to provide an acceptable fine aggregate with regards to sulphate content. This study has been conducted to assess the possibility of using fine aggregate with sulphate content higher than the upper limit of the Iraqi standard (0.5%) to produce pre-cast concrete units: hollow concrete block and paving concrete brick, where the total amount of sulphate has been controlled by decreasing the fine aggregate content in the adopted mixes. The tests are conducted on reference mix with an acceptable fine aggregate according to the Iraqi standard (with regards to sulphate content) and three mixes with fine aggregates contain (1.19, 1.90 and 2.47%) of sulphate respectively. The hollow concrete block and paving concrete brick are produced from all these mixes. The results indicate the possibility of using unacceptable fine aggregate (those with sulphate content higher than 0.5%) to produce an acceptable hollow concrete block and paving concrete brick according to Iraqi specifications. This could be done by reducing the fine aggregate content in the mixtures within a specific limit.
The object of this paper was reduced the heat transferred quantities from or to internal building space by covering it's external walls with many materials, therefore, the researcher build the (1x1x2) m room sample at 3rd floor for building in Baghdad city (L = 33.2 N°), and (1x2)m wall has East orientation , while the other surfaces were insulated by 200 mm styropor sheets, and using Air – Conditioner 0.5 Ton of refrigeration to afford the standard thermal comfort. The researcher found that, the metal sheet painted with thermal plastic paint with 10 mm thermal insulation used as a cover layer for ordinary wall saved 57% from electrical energy consumption in Air-Conditioner, while used that material without insulation layer gives 46.2% , hollow plastic board (for decorative used) gives 42.5% , hollow faced brick with thermal insulation gives 40.22%, solid flooring brick with thermal insulation gives 39.5% , colour metal sheets with air – gap gives 36.4%, asbestos – cement board coated by reflective aluminum paint gives 34%, the ceramic with thermal insulation gives 31.9%, while all the material – marble , porcelene , hallan stone , fiberglass sheets with 10 mm thermal insulation will gives the electrical energy reduction percentage less than 30% .
Composite columns are frequently used in constructing high-rise structures because they can minimize the size of the building's columns while increasing the floor plan's usable space. This study aims to create a nonlinear 3D finite element model for square composite columns designed for solid and hollow columns with various multi-skin tubes subjected to loads at eccentricities of (30 and 60) mm, compressive strength, and mesh size using the ABAQUS software. The comparison was based on the experimental data of six references of composite columns. While the compressive strength of concrete increases, the stiffness of the composite column rise. The ratio of concrete compressive strength values for composite column increased by (0, 12.3, 17.8, and 26.7 percent) for (fc'=25, 31.96, 35, and 40) MPa, respectively. The results of the different mesh sizes (20, 40, and 60) mm are showing; The experimental results and the finite element solution developed using the (20 X20) mm element correspond well. The nonlinear finite element analysis method was used, and the finite element outputs results were confirmed to be in favorable agreement with the experimental data