Conventional in situ construction

Conventional in situ construction 2.1 Introduction In architecture and building, in situ refers to construction which is carried out on the building site using raw materials. In-situ is most commonly a mixture of aggregate (known as builders mix) blended with portland cement and clean water, that is free of oils, acid and others. Portland cement is made from lime, silica, alumina and gypsum with the raw materials being readily available throughout the country. Aggregate meanwhile is most commonly sand, gravel and crushed stone and constitutes 60 to 75pc of the volume of most concretes. In-situ concrete is strong, durable, stable, readily available and relatively economic in terms of construction and life time maintenance. It is the ideal structural material, in building sites that have difficult access. Other qualities that make it an ideal construction medium include the ability to control of form and shape, the enclosure of space and structure in one material, its compatibilty with most other materials, the ability to form integral surface finishes and colour of its compatibilty with most other materials. In-situ concrete structure usually used in industrial and commercial service industry such as school,hospital and hotel.The basic form of in-situ concrete structure are columns, beams, walls and floor. Compare that withprefabricatedconstruction, in which building components are made in a factory and then transported to the building site for assembly unlike insitu method of construction. Conventional building method or in situ construction method, is also defined as components of the building that are made at site through the processes of timber or plywood formwork installation, steel reinforcement, and cast in situ. Conventional buildings are mostly built of reinforced concrete frames. The traditional construction method uses wooden formwork. It is much more costly for construction which includes labour, raw material,transportation and low speed of construction time. This system is suitable for a country where unskilled labour is limited. There is no heavy machinery or high technolog y involved compare to precast method. 2.2 Advantages of using in situ The objective of an in situ method is to eliminate and reduce the traditional site-based trades like traditional timber formwork, brickwork, plastering and to reduce labour content. By using in situ method, alteration can be made at the last minute, design can be proceed as the structure is built and the rates of the production can be fast. 2.3 Disadvantages of using in situ However, conventional in-situ construction method also have their own disadvantages. It will lead to the higher amount of wastage compare to precast method. For example, in term of mixture of cement,sand and aggregates. It also require all activities involve high labour and plant on site. Besides,construction is also influenced by the weather and the reinforcement and formwork tend to be labour intensive.