Research Abstract:

The use of self-compacting high-performance concrete has increased dramatically as a result of its multiple use following its recent discovery in Japan in 1980, as it can be pumped to very high places or used in confined spaces where the rebar is found with a high density without having to use any mechanical energy for compacting this type of concrete .

Following the recent war in the Gaza Strip, the Israeli forces demolished several buildings , the burden to restore many of these buildings has become a great concern ever since. The self-compacting concrete can be used in the restoration of many of the structural elements, however given the high-quality properties of concrete, restoration work of these elements shall be much easier as opposed to using traditional concrete .

The theme of ​​this study is based on the production of self- compacting high-performance concrete by using locally available materials in addition to examining the mechanical properties and how they interact over extended periods of time , more particularly the shrinkage property which is one of the aspects greatly considered by the international standards, as accelerated shrinkage of concrete causes significant deformations which may eventually lead to its crumbling or collapse.

This study is a scientific and practical study which is based on conducting laboratory experiments through the creation of multiple admixtures of self-compacting high-performance concrete and conducting the necessary tests on short and long terms , as well as exploring the impact of using iron fibers and polypropylene fibers on the performance of the concrete.

This study also aims to determine the ideal ratios of the iron and polypropylene fibers amount, and then use the results of these tests to produce the best concrete admixture that conforms to the relevant American specifications by using locally available materials.

 

Research objectives:

 To produce self-compacting high-performance concrete using local materials .

 To measure shrinkage capacity of self-compacting concrete .

 To determine the implications of the different ratios on the mechanical properties of concrete.

 To identify the impact of using iron and polypropylene fibers on the dynamic qualities of concrete and determine the ideal ratios.

 To dispose large amounts of debris left behind as a result of the demolition of buildings during the recent war on Gaza using eco-friendly methods.

 To supply the Palestinian market with this kind of self-compacting high-performance concrete as this type of concrete is being heavily used in the repair work which the Gaza Strip lacks significantly.

 

Background of research proposal: (previous work which has been accomplished in this field and the contribution this research is going to make):

The theme of ​​the research is based on mechanical properties and shrinkage of the high-performance self-compacting concrete using local materials . This research comes as part of a series of master's research and graduation theses for producing high- performance concrete and self-compacting concrete on a separate basis, hence the properties of fresh and mechanical properties such as stress-strain, tensile and bending moment have been essentially examined, however the behavior of concrete in the long run, for instance its shrinkage property, has a great role in the performance of concrete in the medium and long run. It is known that the availability of properties such as fresh concrete with high strength and good elastoplasticity without having properties that are suitable for shrinkage leads to not using such types of concrete in the engineering activities . Therefore, we need to work on improving the shrinkage properties of this kind of concrete, the shrinkage property will be further examined and verified through numerous tests on concrete admixtures to obtain the best outcomes. Further, we will study the effect of using polypropylene to improve the shrinkage property of self-compacting concrete and its effect on the compressive strength and other properties such as tensile and bending moment . We will examine the impact of using recycled aggregates on the fresh properties and durability of self-compacting and high-performance concrete.

There have been numerous studies on the use of recycled aggregates in concrete admixtures, the researcher (Zuhd, 2008) studied the impact of replacing natural aggregates with recycled aggregate (used aggregates) and its impact on the resistance capacity of concrete under compressive and tensile strength.

(Abed , 2009) also used recycled aggregates in the production of building and interlocked blocks, these products conformed to the required specifications. The researchers (Bisiso et.al., 2010) used recycled aggregates in asphalt pavement.

 

Research Methodology ( how to plan for solving the research problem, and the strategy to be followed in the study )

 To study previous literature .

To determine laboratory tests program.

 To procure the materials needed to complete the work .

To manufacture some of the equipment required for carrying out the tests (such as load frame equipment with its accessory devices)

         Implementation of the testing program .

         Presenting, discussing and comparing results with previous work.

         Study conclusion and recommendations

         Checking report formatting.

         Publish research in scientific peer-reviewed journals.

 

The contribution of the research in addressing the issues of the community or the development of knowledge (the extent to which the research is relevant to the needs of the research community and the possibility of applying the results within local institutions or its contribution in sharing knowledge)

The Gaza Strip is currently suffering from a problem which was discussed by the syndicate of engineers and the USAID, namely the size of the debris resulting from the recent war on the Gaza Strip and the difficulty of disposing it in light of the severe shortage of natural aggregates which are usually imported from abroad , such a fact has recently paralyzed the movement of construction and reconstruction materials, this research, on one hand, aims to solve the problems through the use of the rubble of destroyed buildings as an alternative to natural aggregates and hence allow us to able to overcome the problems associated with the rubble of destroyed buildings, find an alternative for the natural debris, and use it as a reliable component based on several studies .

On the other hand,  the research aims to produce self-compacting concrete using local materials and recycled rubble to improve concrete shrinkage properties using polypropylene and study the impact on the compressive strength and other properties such as tensile and bending moment.

Self-compacting concrete does not require any mechanical tools (vibrator) during the casting phase , so it is used to strengthen the structural elements in narrow places and where rebar is found with high density which is one of the urgent requirements of the Gaza strip at the present time.