Civil Engineering Today

  Aggregates Aggregates are raw materials that are produced from natural sources and extracted from pits and quarries, crushed stone and recycled concrete, used in construction. Aggregates are the major and important constituent of concrete. They form the body of the concrete as it occupies 70–80% of the volume of concrete. Although aggregates were originally considered to be inert material, they have recently been found to be chemically active to some extent. Cement is the only factory-made component, whereas aggregates (both coarse and fine) and water are naturally available materials. Aggregates are the important constituents of the concrete which give body to the concrete and also reduce shrinkage.     Classification of Aggregates I.   Classification of Aggregates Based on Size: Aggregates are available in nature in different sizes. The size of aggregate used may be related to the mix proportions, type of work etc. The size distribution of aggregates ...

  WOOD PRODUCTS The common industrial timber products are: 1. VENEERS - Timber veneer is a decorative building material comprising thin slices of timber glued onto wooden board , particle board or fibreboard .  It has been favoured by builders and designers since ancient times as the finest and most efficient use of the valuable timbers.  Veneer is produced as a thin layer of timber that is uniform in thickness.  The veneer is normally between 0.5 and 0.85mm thick .  Timber veneer is from a natural and renewable resource competing with non-renewable commodities like steel, aluminum and plastics.  The surface coverage of veneer is approximately forty times more than 25mm timber, which makes it the most economical way of utilizing precious wood.  One cubic metre of log produces around 1,000 square metres of real timber in veneer form.  No other form of wood working material results in such an efficient use with minimal wastage.   ...

    SEASONING OF TIMBER Seasoning is the process of reducing moisture content in a freshly cut tree to the desired level. In other words, Reduction of moisture content along with improving some qualities before the use of woods is called seasoning of timber. By seasoning, generally, the moisture is reduced to about 15% where new cut woods bear about 50%. Timber is wood that is used for building houses and making furniture. Basically, timbers are used for structural purposes. Those woods, which are adapted for building purpose, are timber. When the trees are cut down, it will be having approximately 50% of moisture content. Timber cannot be used immediately after the cutting of trees because of the tree contains an uneven sap. If the excess moisture is present within the timber will shrink excessively.It will even have a tendency to decay so, there is the only seasoning of timber is one of the solutions. The 100% amount of the moisture cannot be removed from the Tree...