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
Aim To determine volume of concrete per bag of cement, where nominal maximum size of aggregate does not exceed 38 mm. Apparatus Balance – Sensitive to 0.01 kg Tamping bar – Length 38 cm, Weight 1.8 kg Cylindrical mould – Dia = 250 mm, Height = 280 mm, Capacity = 0.01m3 Procedure Step-1 (Measuring Volume … Read more
What is Crazing on Concrete Surface? Crazing is the development of fine shallow hair cracks on create surface. Due to crazing the surface appearance of concrete looks not so pleasing. This may appear within few day after curing or sometimes after a longer periods. These cracks do not penetrate deep onto the concrete and do … Read more
What is Slump Loss in Concrete? Slump value is of great importance when concrete is in its fresh state. Slump value represents the workability property of concrete. Due to its importance, the value of slump is generally specified by the designer. And while working on site, the engineer’s responsibility is to make sure that the … Read more
Sulphates present in soil or water can cause serious damages to concrete. The methods given below can be adopted to protect concrete from sulphate attack. Use of Sulphate Resisting Cement The most efficient method of resisting the sulphate attack is to use cement with the low C3A content. It has been found that a C3A … Read more
Factors Affecting Strength Test Results of Concrete Compressive strength is the most important property of concrete. The compressive strength of concrete is determined in the laboratory in controlled conditions. On the basis of this test result we judge the quality of concrete. But sometimes the strength test results vary so widely that it becomes difficult … Read more
Capping of Concrete Cylinders Capping is required to give a smooth surface for applying compressive load to concrete cylinders. Only cylindrical concrete test specimens are capped using appropriate method. When the ends of cylindrical test specimens are not plane within 0.05 mm, it is required to cap those test specimens. The capped surfaces should be … Read more