PROCEDURE FOR PLACING OF CONCRETE: Before any concrete is placed the entire placing programme consisting of equipment, layout, proposed procedures and methods is planned and no concrete is placed until formwork is inspected and found suitable for placement. Equipment for conveying concrete should be of such size and design as to ensure a practically continuous(…)
Work Procedures
POLYURETHANE WATERPROOFING OF ROOF SLAB
Polyurethane Waterproofing of Roof Slab Polyurethane waterproofing of roof slab consists of two pack clear/pigmented Aliphatic Polyurethane using Polyether Polyols with Iso-cynorate for rendering flame resistant characteristic. The two pack system consisting of pigment and the solvent (Xylene/Toulene, no filter) is mixed in definite ratio by weight strictly as per manufacturers specification for preparing the(…)
COLD JOINT IN CONCRETE
What is Cold Joint in Concrete? An advancing face of a concrete pour, which could not be covered by fresh concrete before expiry of initial setting time (due to an unscheduled stoppage or delay on account of breakdown in plant, inclement weather, low rate of placement or any other reason), is called a cold joint.(…)
WORKABILITY TESTS AT SITE & RECOMMENDED VALUES
What is workability of concrete? Which test is generally performed at site for its determination? And what are its recommended values for different purposes? Workability of concrete describes the ease or difficulty with which the concrete is handled, transported and placed between the forms with minimum loss of homogeneity. Workability is important because, if i.(…)
SPECIFICATIONS FOR JOINTS IN CONCRETE
Joints in concrete structures such as contraction joints and expansion joints are required to be provided to prevent cracks in concrete at hardened state. To provide these joints, there certain specification which must be followed. These specifications are explained below: Specifications for Construction joints: A construction joint is defined as a joint in the concrete(…)
SEQUENCE OF WORKS FOR EXCAVATION AND BACKFILLING
Earthwork in excavation upto required depth is required for construction of foundation. It is a very important part of construction process, and care must be taken while excavation in safety perspective. Different soil layers may be encountered while excavation, dewatering may be needed sometimes. These points must be kept in mind to take necessary action(…)
POOR CONSTRUCTION METHODS AND WORKMANSHIP
Poor construction methods and workmanship is responsible for the failure of buildings and structure. The poor construction methods and workmanship is caused due to negligence and inadequate quality control at construction site. The effects of some of the poor construction methods are discussed below: (a) Incorrect placement of steel Incorrect placement of steel can result(…)
AVOIDING COMMON CONCRETING PROBLEMS
There are a number of problems which can occur in concrete as a result of improper mixing, placing, or curing. The following are common problems that are easily avoided if proper procedures are followed. Segregation is the tendency of the various constituents of a concrete mix to separate, especially the separation of the large aggregate(…)