INGREDIENTS OF CONCRETE
b) COARSE AGGREGATE
c) FINE AGGREGATE
f ) AIR
WHY QUALITY CONTROL OF CONCRETE IS IMPORTANT ?
The quality control of concrete is done in three stages
a) Production stage ( On fresh concrete before placing)
b) Hardened stage ( hardened concrete specimens)
c) On structures ( tests done on the structures )
TESTS TO BE DONE ON FRESH CONCRETE
a) SLUMP TEST
b) Compaction Factor test
c) Vee- Bee Test
d) k slump test
e) Kelly ball test
f ) Flow table test
TESTS TO BE DONE ON HARDENED CONCRETE
a) COMPRESSIVE STRENGTH TEST (CUBE TEST)
b) WATER PERMEABILITY TEST
c) WATER ABSORPTION TEST
NON DESTRUCTIVE TESTS ON STRUCTURES
a) REBOUND HAMMER
b) UPV TEST
CONCRETE CORE TEST
WHAT IS A SLUMP TEST?
Slump cone test is to determine the workability or consistency of a concrete mix prepared at the laboratory . Slump test shall be done on fresh concrete immediately after production at the batching plant to ensure the workability is in line with the design mix requirements and also at the pour point immediately after releasing from the transit mixture.
HOW DO YOU DO A SLUMP TEST (AS PER IS 1199:1959 REAFFIRMED 2013)
The nominal size of the aggregate shall be less than 38 mm . The cone has 20cm bottom diameter and 10 cm top diameter. The height of the cone is 30 mm. It consists of a 16 mm tamping rod having a length of 600 mm
The mould shall be filled in four layers, each approximately one-quarter of the height of the mould. Each layer shall be tamped with twenty-five strokes of the rounded end of the tamping rod. The cone is removed gently and the decrease in the height of concrete is the slump of concrete.
The slump tolerance shall be +/- 25 mm . If a design mix recommends a slump of 100 mm it cant go beyond 125 mm and go below 75 mm.