Concrete is one of the most important materials for construction industry. The material in the mixture of concrete includes cement, sand and coarse aggregate. Production of cement causes the air pollution from the emission of carbon dioxide to the air. This research studies the replacement of cement with palm oil fuel ash (POFA) in the concrete mixture. The objective of this research is to investigate the compressive strength of concrete and water absorption rate of concrete made from POFA and to compare the strength and absorption rate between conventional concrete and concrete made from POFA. This is to indicate whether the compressive strength and absorption rate are equivalent to the strength of conventional concrete. The methodology used in this research is experimental method and the palm oil fuel ash was taken from palm oil mill in Cha’ah, Johor, Malaysia. The results of this research are the specimens which contain 20% POFA has a compressive strength and water absorption rate comparable to conventional concrete.

Dredged sediment can be used in producing bricks for geotechnical engineering purposes including construction of foundations, retaining walls and roads. This study was conducted to determine the strength of brick made from dredged sediments and comparing them with the strength of normal brick. This study was conducted in an experimental form that involves collecting dredged sediment in the river of Sungai Bebar, Pahang, Malaysia and the river of Sungai Setiawan, Perak, Malaysia for analysis. It also involved the use of materials and equipment from laboratory to test the strength of brick. The results obtained from the analysis of data showed that the strength of brick exceeded the standard value for ordinary brick in Malaysia’s standard. This support the fact that the brick made from dredged sediment can be used in Malaysian construction industry. The result of this study helps to reduce the volume of dredged sediment to be disposed and to avoid geo-hazards from dredging activities.

Sea and river dredging has produced a large volume of dredged waste over the years which could trigger geo-hazards including dispersion of contamination from sediments. One of the ways to overcome this issue is by incorporating it into geotechnical engineering purposes including the production of concrete for foundation, retaining wall and highway construction. This research aims to investigate the strength of concrete made from dredged sediments and to compare it with the strength of conventional concrete. This research emphasises on the usage of two types of dredge waste; silt and sand, obtained from Kuala Perlis, Perlis and Sungai Bebar, Pahang, respectively. The dredged sediments from Sungai Bebar will be used as fine aggregates while sediments from Kuala Perlis will be used as admixtures and fine aggregates for production of concrete. The concrete will then be tested for its strength. As a result, the concrete made from these two rivers are able to produce the minimum strength requirement for C20 concrete mix. This enables the concrete mixtures used in this research to be applied in the construction of foundation, retaining wall and highway. This research helps in reducing the amount of wastage from dredge work as well as providing a new material source for concrete.

The primary objective of this study is to determine trace metal contamination in environmental samples obtained from Pahang River and Kelantan River, Malaysia which may help to identify the risk of sustainable dredging in these areas. This research also proceeds to compare the trace metal concentration with the National Water Quality Standards of Malaysia, Interim Canadian Sediment Quality Guidelines and Malaysian Food Act 1983 to determine its limits and risks. Samples of water, sediment, snails and fishes were collected and analyzed for As, Cu, Cd, Cr, Fe, Pb, Ni, Mn, and Hg by using atomic absorption spectrophotometer. It was found that the concentration of trace metals namely As, Cu, Cd, Cr, Pb, Ni, and Hg in river water, sediment, snail and fish samples in Pahang River were lower than the maximum allowable limits, except for Fe and Mn. In Kelantan River, the concentration of trace metals indicating that it is contaminated with Fe, Mn, Pb, Cr, Cu, Hg, and As as all trace metals exceeded the maximum allowable limits. Negative impacts may arise, and the river may contaminate more in future if there is no proper management to tackle this issue during execution of dredging activities.

Dredging works are commonly described as removal of sediments from underwater which involving excavation process. Soil and rocks are excavated for channel and harbor deepening and for land reclamation. Land reclamation is defined as usage of dredged sediments to construct or build new land in the sea. This research aims to investigate the impact of dredging and reclamation projects as dredging and reclamation are one of the geotechnical engineering elements. Human activities such as dredging and reclamation may lead to geo-hazards such as coastal erosion, landslides, flooding and etc. In this research, 157 villagers from Teluk Rampang and Langkah Baik, Pengerang, Kota Tinggi in Malaysia has been selected as respondents to answer the distributed questionnaire. As a result, the analysis shows that villagers become victims due to the reclamation project executed to construct petroleum hub in Pengerang, Kota Tinggi. The impact can be reduced with a proper monitoring and management by the project stakeholders’.