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 aim of this research is to produce lightweight cement mortar with properties better than reference ordinary cement mortar. Porcelanite stone were utilized as lightweight aggregate with a volumetric partial substitution of fine aggregate. The process includes using different percentages (5, 10, 15 and 20 %) of pre-wetted (24hr.) porcelanite to produce lightweight mortar with internal curing. Water curing was used for reference mortar mixture and air curing for the other mixtures of porcelanite substitution. Compressive strength, flexural strength, density and ultrasonic pulse velocity for different ages (7, 14 and 28 days) have been tested. The results show an improvement in the properties of cement mortar especially in replacement percentage of 10 %.
Sustainable buildings reflect the interest rising of Urbanism sectors in issues of economic development, optimal utilization of natural resources and greater reliance on "renewable" sources of energy. The objective of the research is to identify and Diagnosis the priority of alternatives to sustainable projects with the of relative importance and to review the value engineering indicators in building and the possibility of applying sustainable building standards such as British Standards (BREEAM), US Standards (LEED), Pearl Rating System and Green Pyramid Assessment System. The research is based on four axes. The first axis is the foundations of architectural design to serve the optimum use of the available resources. The second axis is based on the methods of producing building materials with optimum use of natural resources; Third axis: The sustainable use of the building to achieve conservation of the environment using economical sources of energy, waste recycling and maintenance of the building according to the required specifications. The fourth axis, which means Using renewable energies to provide the building with the energy it needs. The literature and researches in the field of research work were reviewed, which included the concept of applying value engineering method in the sustainable buildings and the most important areas of their applications during the stages of completion of the project and what are the basic considerations that should be provided in the construction projects, Which represents the practical aspect in relation to the various stages of the field study, which includes aspects related to the field survey, through the preparation and Configure of questionnaires derived from the theoretical study and interviews and also focused on the indicators and areas of applications during the stages of the project (pre-construction stage, implementation stage, A maintenance and operation, post-construction phase (end of the age of the building) and what are the basic considerations that must be provided in the construction projects. The research provided this results: The Sustainable Buildings Projects location Selection Index is The most important indicators of value engineering for sustainable buildings where relative importance of it is 72%, according to the respondents' answers, conversely the architectural index, with its relative importance of 55%, while the electromechanical index was 68% and the constructional index by 65%. And the development of a waste management program during the process of construction and operation so that this program achieves the minimum recycling and the use of new alternatives to building materials drawing on what has been developed within other areas in the development of the construction industry.
Composite beams, made up of a concrete slab and steel in the IPE steel section, are commonly used in bridges and buildings. Their main function is to enhance structural efficiency by merging the compressive strength of concrete with the tensile resistance of steel, thereby improving overall stiffness, ductility, and load-bearing capacity. This study offers an extensive review of the flexural behavior of steel-concrete composite beams, focusing on the interplay of concrete strength, shear connector types, and interaction levels in determining structural performance. It integrates experimental and numerical research to analyze critical parameters, including load-deflection behavior, shear transfer efficiency, and crack propagation at the steel-concrete interface. The study emphasizes the effect of concrete compressive strength, particularly in ultra-high-performance concrete (UHPC) and lightweight concrete, on stiffness, ductility, and load-bearing capacity while reducing self-weight and enhancing sustainability. The study revealed that fully bonded shear connectors, using CFRP sheets and welded plates, enhance flexural capacity and stiffness. In contrast, partial bonding or pre-debonding reduces performance due to crack propagation. Indented and hot-rolled U-section connectors enhance interaction and minimize slip, while uniform distribution of shear connectors optimizes load capacity and stiffness. Lightweight concrete decreases slab weight without compromising performance, and high-performance materials such as ECC, SFRC, and UHPFRC improve strength and ductility. Numerical modeling, particularly finite element methods, and higher-order beam theories validate experimental results, providing accurate tools for predicting structural behavior under various loading and environmental conditions.