Carbonation of Concrete Carbonation of concrete is one of the reasons for corrosion of reinforcement. It is a process by which carbon dioxide from air penetrates into the concrete and reacts with calcium hydroxide to form calcium carbonates. The percentage of CO2 present is air vary from place to place. In case of rural areas … Read more
For the same strength or workability, concrete with large size aggregate will require lesser quantity of cement than concrete with a smaller size aggregate. In a mass concrete work the use of larger size aggregate will be useful due to the lesser consumption of cement. This will also reduce the heat of hydration and the … Read more
Prestressed Concrete Prestressed concrete is a modified form of reinforced concrete. it not only eliminates the weakness of concrete, but also makes it possible to take full advantage of compressive strength of concrete. The term “Prestressed Concrete” is applied to those reinforced concrete members in which concrete is subjected to compressive stresses, before the external … Read more
Points to Consider Mixing of mineral admixtures with OPC at site should not normally be permitted. However for projects requiring use of blended cement from durability and strength considerations, which is not available from the cement manufacturer blending may be permitted through a specific facility created at site with complete automated process control to achieve … Read more
Finishing may be defined as the process of leveling, smoothing, compacting and otherwise treating surface of fresh concrete or recently placed concrete to produce desired appearance. Steps Involved for Finishing Concrete There are 3 different steps involved for finishing concrete, which are as given below. Screeding Floating Trowelling 1. Screeding (Step-1) This is the process … Read more
Removal of Forms Forms should not be removed until the concrete has sufficiently hardened in order that it can carry safely its own weight and any other live loads it is subjected to. The supporting period (period between placing of concrete in forms and removal of forms) differ according to the type of cement used … Read more
Careful supervision during concrete manufacture is necessary for all concreting operations such as batching, mixing, transporting, laying, compacting and curing. While inspecting concreting work following points should be remembered for effective quality control. Inspection during Concreting The concrete mix should be designed in the laboratory with the materials to be used in the field. Weight … Read more
Great care is to be taken to keep the repaired patches moist for several days. In general much amount of care is taken to cure material in patches than the whole structure. The reason is, being relatively small volume of repairs and the tendency of old concrete, around it, to absorb moisture from the new … Read more
This method is used for repairing holes having a depth nearly equal to greater than the least surface dimension, i.e. for any holes and narrow slots cut for the repair of cracks. This method is not used for shallow depressions; for filling patches where reinforcement is exposed or holes which extend through and through wall … Read more
The following 4 mineral admixtures can be used for making concrete. Rice husk ash Metakaolin Silica fume Fly as 1. Rice Husk Ash It is obtained by burning the rice husk in a controlled manner without causing environmental pollution. This is generated in huge quantity in the rice shelters and each tone of paddy produce … Read more