Effects of palm oil clinker as coarse aggregates replacement in self curing concrete

Concrete, if properly design, can be one of the most durable material and widely used in construction due to its availability and good compressive strength. A good quality concrete can be produced not only through good design of concrete mix proportions but also good and proper curing process that ensure a complete hydration process of the cement. However, sometimes proper curing process was not provided during concreting on site due to various reasons. This study investigates the effects of 10 mm crushed Palm Oil Clinker (POC) as partial aggregates replacement to act as internal reservoirs in concrete to provide internal curing process of cement. This process or technique is also popularly known as self-curing process for concrete. The POC which has the density of 780 kg/m3 was used to replace 20% of the coarse aggregates. A water/cement ratio of 0.53 was used in the concrete mix design. Three different curing conditions were employed, namely, normal water curing, air curing and 7 days in water plus outside curing conditions. The workability of the POC and control concretes was determined through slump test. The concrete samples were tested for compression at the age of 3, 7 and 28 days while concrete prisms and cylindrical samples were tested at the age of 7 and 28 days. The experimental results show that the inclusion of POC was found to increase the workability of concrete by 27% but reduced the concrete compressive strength by about 6% compared with the control concrete. In addition, the flexural and tensile strengths of POC concrete were found to be less than the control concrete due to the properties of the POC which was lightweight and porous. The experimental results show that the porous structure of the POC aggregates can be utilised as water reservoir for the process of internal curing for the self-curing concrete

Behaviour of treated rubberised fiber concretes at higher temperatures

The fundamental aim of this study is to determine the effect of high temperature on the behavior of concrete consists NaOH treated rubber and steel fibers (TRSF-Con). During the experiment, four different concrete mixes were prepared; the first one is the control mix (CM) which was made with natural coarse and fine aggregates, cement, and water, while the other three concrete mixes were with the replacement rates of 10%, 20% and 25% of the natural coarse and fine aggregates by TRSF from used tires. The specimens were exposed for a period of 1 hour to design temperature-time curve up to 800°C followed by cooling to room temperature. Compressive strength, flexural strength, weight loss were determined and compared with that of control specimens. The ductility of the concrete increased with the increased of TRSF contents, increases the damping properties, and while the compressive strength of the concrete reduced with the increment of TRSF contents. Although data obtained in all parameters where lover than the control specimens, concrete containing treated rubber and steel fiber can be suitable for non-structural member in concrete and driveways or road constructions