Carbonation is the term used to describe the effect of carbon dioxide on a material. The phenomenon rarely leads to structural problems but carbonation-induced corrosion can lead to unsightly spalling on structures. The repair costs, for example to multi-storey office development façades, can be considerable. Carbonation of cementitious materials results in a lowering of the …
Aggregates: Effects and Classification Aggregates constitute a skeleton of concrete. Approximately three-quarters of the volume of conventional concrete is occupied by aggregate. It is inevitable that a constituent occupying such a large percentage of the mass should contribute important properties to both the fresh and hardened product. Aggregate is usually viewed as an inert dispersion …
Rodded Unit Weight of Coarse Aggregates PURPOSE Determination of the unit weight of coarse aggregates in a compacted condition. This test method is applicable to aggregates not exceeding 15 cm in nominal size. The unit weight so determined is necessary for the design of a concrete mixture by the absolute value methodز EQUIPMENT AND MATERIALS …
Selection of the Construction Plant The selection of plant is usually straightforward but the following points are relevant. 1- Cost a- Hire rate Take all factors into account if you are offered alternatives. What are the extras to the basic rate? For operated plant, these can include overtime, bonus and subsistence. Are fuel and lubricants included …
Concrete in Compression It is generally accepted that the behavior of a reinforced concrete member under load depends on the stress–strain relationship of the materials, as well as the type of stress to which it is subjected. With concrete used principally in compression, the compressive stress–strain curve is of primary interest. The compressive strength of concrete …
Concrete in Tension: Tensile Strength of Concrete The tensile and compressive strengths of concrete are not proportional, and an increase in compressive strength is accompanied by an appreciably smaller percentage increase in tensile strength. According to the ACI Code Commentary, the tensile strength of normal-weight concrete in flexure is about 10% to 15% of the …
Structural Design and Limit States Aims and methods of design Codes state that the aim of design is the achievement of an acceptable probability that the structure will perform satisfactorily during its life. It must carry the loads safely, not deform excessively and have adequate durability and resistance to effects of misuse and fire. Codes recognize …
There is no generally accepted method of directly measuring the amount of work necessary to achieve full compaction, which is a definition of workability. Probably the best test yet available uses the inverse approach: the degree of compaction achieved by a standard amount of work is determined. The work applied includes perforce the work done …