Maintenance of Concrete Structures: Modern concrete is a very durable construction material and, if properly proportioned and placed, will give very long service under normal conditions. Many concrete structures, however, were constructed using early concrete technology, and they have already provided well over 50 years of service under harsh conditions. Such concrete must be inspected(…)
EXPOSURE CONDITIONS AFFECTING DURABILITY OF CONCRETE
There are five levels of environment exposure of concrete for which durability requirements of concrete depends. These are: Mild exposure Moderate exposure Severe exposure Very severe exposure, and Extreme exposure. These are the environments to which the concrete will be exposed during its working life. The durability requirement, like clear cover to reinforcement steel is(…)
DETAILING OF RCC BEAMS
Detailing of Beams ? Beam carries transverse external loads that cause bending moment, shear forces and in some cases torsion ? Concrete is strong in compression and very weak in tension. ? Steel reinforcement is used to take up tensile stresses in reinforced concrete beams. ? Mild steel bars or Deformed or High yield strength(…)
BENEFITS OF USING STEEL FIBRES IN CONCRETE
The use of steel fibre in concrete can improve its many properties. The benefits of using steel fibres in concrete are as follows: 1. Steel Fibres are generally distributed throughout a given cross section whereas reinforcing bars or wires are placed only where required 2. Steel fibres are relatively short and closely spaced as compared(…)
HIGH PERFORMANCE CONCRETE COMPOSITION & FEATURES
The composition of high performance concrete (HPC) are almost same as those of Conventional Cement Concretes( CCC ). But, because of lower Water Cement Ratio, presence of Pozzolans and chemical admixtures etc., the HPCs usually have many features which distinguish them from CCCs. From practical considerations, in concrete constructions, apart from the final strength, the(…)
QUANTITY & RATE ANALYSIS FOR REINFORCED CONCRETE
Today we will see how to prepare rate analysis for Reinforced Concrete (RCC) work. First step to rate analysis is the estimation of labour, materials, equipments and miscellaneous items for particular quantity of reinforced concrete. The second step is to determine the component of structure for which the RCC rate analysis is required, as the(…)
DESIGN OF SLAB – BASICS
DESIGN OF SLAB Slabs are generally designed on the assumption that they consists of a number of beams of breadth ‘one meter’. Effective Span The effective span of a simply supported slab shall be taken as the lesser of the following: Distance between the centers of bearings, Clear span plus effective depth Thickness of Slab(…)
PRE-CONCRETE CHECKS FOR FORMWORK & RELEASE AGENTS
PRE-CONCRETE CHECKS FOR FORMWORK: Before the concrete is poured into the formwork, it must be checked by someone who has been trained to inspect formwork. Depending on how big or complicated the pour is, the inspection may just take few minutes or it could take hours. Only when the formwork has been approved, may the(…)