Roslli Noor Mohamed

Development of Self-compacting Concrete Using Palm Oil Clinker as Lightweight Aggregate

This chapter reports the study of development of self-compacting lightweight concrete using lightweight aggregate. In this study, palm oil clinker (POC) is used to replace normal gravel as course aggregate in concrete. There are two types of mix designs in this project, which are the normal self-compacting concrete as the control mix and the POC mix with 100% POC replacement for course aggregate. Slump flow test is carried out to measure the workability of the concrete. Compressive strength test is conducted using cubes for these two types of concrete mix at the age of 7 and 28 days. Splitting tensile and flexural strength test were also conducted using cylinders and prism, respectively, at the age of 28 days and were also wet-cured. The result shows that by using POC as lightweight aggregate, lightweight self-compacting concrete with high workability and strength almost similar to normal self-compacting concrete can be produced. This study also analyzes characteristics of 500 mm × 500 mm wall with thickness 125 mm under vertical load using both types of mix design. Throughout the test, data such as load capacity, behavior of cracks, and failure mode were observed. The test results showed that specimens with POC achieved almost similar performance in terms of ultimate load capacity with only 14.3% difference.

Performance of Grouted Splice Sleeves with Tapered Bars under Axial Tension

Many structural failures in precast concrete buildings are initiated by connection failures. To avoid such failures, the connections should have enough strength to join the reinforcement bars between precast concrete panels. This paper presents the structural performance and behaviour of a proposed splice sleeve connection using generic steel pipe. The connection consisted of steel bars with tapered nuts confined in grouted steel pipes. The connections were subjected to increasing axial tension until failure. The results show that the use of smaller pipes gives better confinement effects and provide higher bond strength. A short embedment length of about 10 times rebar diameter is able to provide full tensile strength of the connected rebars. As compared to long embedment length of conventional lapping of steel bars, the proposed connection is able to provide structural continuity with short embedment length.

Performance based design of self-compacting concrete incorporating class F fly ash

The application of self-compacting concrete (SCC) in speeding the development of construction technology has become a growing trend due to its known advantages. It is now well established since it has three significant properties which are flowing or filling ability, passing ability and segregation resistance as the main self-compactability characteristics. As a result of all these capability, SCC has increased the workability in the fresh concrete properties while maintaining or even increase the strength in hardened concrete properties. This study presents an experimental study on the performance based design of self-compacting concrete incorporating Class F fly ash where a total of 6 cubes, 3 cylinders and 3 prisms were cast and tested to failure while another 6 cubes, 3 cylinders and 3 prisms were also prepared for the normal concrete (NC) as control specimens. The mix design of SCC was established based on limited water-powder ratio to meet the self-compactability characteristics. The performance of SCC was studied through the fresh concrete properties as well as the mechanical properties of hardened concrete. Experimental results on the fresh and hardened properties of SCC mix design indicated that both workability and strength of self-compacting concrete were found to be higher compared to the normal concrete.