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TECHNICAL PAPER

table 1: Properties of PPC table 2: Properties of aggregates
PRoPeRties vALUe obtAineD PRoPeRties vALUe obtAineD
Normal consistency 31.6% Specific gravity of FA 2.72
Initial setting time 85 minutes
Fineness modulus of FA 2.56
Final setting time 225 minutes
Moisture present in FA 2.16%
Specific gravity 2.92
Water absorption of FA 1.05%
3-days compressive strength of 70.6 18.05 MPa
mm cube sample Grading zone of FA III
7-days compressive strength of 70.6 25.08 MPa Specific gravity of 10 mm CA 2.67
mm cube sample Fineness modulus of 10 mm CA 6.34
28-days compressive strength of 70.6 38.12 MPa Water absorption of 10 mm CA 0.51%
mm cube sample
Fineness (i.e., by using 90µ sieve) 0.67 % Specific gravity of 20 mm CA 2.62
Soundness (i.e., by using Le-Chatelier’s 2.5 mm Fineness modulus of 20 mm CA 7.31
apparatus) Water absorption of 20 mm CA 0.43%
2.1.2 Aggregates minimum strength and durability. In general, mix proportioning
is carried out for a particular compressive strength requirement
Locally available natural sand, conforming to IS 383 was used ascertaining that the fresh concrete is having the adequate
[18]
as fine aggregate (FA). Local aggregates of size 20 mm and workability without any segregation and bleeding. The physical
10 mm conforming to IS 383 were used as coarse aggregates properties of materials (i.e. Tables 1 and 2) were used in the
(CA). Well graded coarse aggregates 20 mm and 10 mm were design of mix proportioning to produce the different grades of
combined in the proportion as 60:40 by mass. The physical concretes , conforming to IS 456 and IS 10262 .
[19]
[20]
[1]
properties of aggregates, required for mix proportioning, are
presented in Table 2. In this study, five different grades (i.e. M15-M35) of low
and medium strength concretes were considered for the
2.1.3 Water investigation. In each grade, three different types of mix were
prepared by varying the water/cement ratios. The quantity
Ordinary potable water was used in preparing the mixtures.
of water, cement, fine and coarse aggregates required to
make one cubic meter of concrete was calculated and are
2.2 Mix Design
presented in Table 3 for the different grades of concretes. The
Mix design is a process of selecting and proportioning the produced concretes were classified into two groups, i.e., low
ingredients in right proportion to produce good quality strength (M15 and M20) and medium strength (M25, M30, and
concrete as economically as possible to achieve the required M35) concretes. According to IS 456 clause 7.1, the degree
table 3: Mix proportion of concretes
tyPe of gRADe of sLUmP W/c cement fA 10 mm 20 mm WAteR
concRete concRete (mm) RAtio (kg/m ) (kg/m ) cA (kg/m ) cA (kg/m ) (kg/m )
3
3
3
3
3
Low M 15 25-50 0.60 255 655.35 516.12 774.18 153.00
strength 50-75 0.58 280 658.00 500.64 750.96 162.40
concrete 75-100 0.55 318 674.16 475.59 713.59 174.90
M 20 25-50 0.51 346 671.24 476.10 714.14 176.46
50-75 0.48 388 628.56 473.36 710.04 186.24
75-100 0.47 408 624.24 463.49 695.23 191.76
Medium M 25 25-50 0.49 384 610.56 482.30 723.46 188.16
strength 50-75 0.47 410 582.20 480.52 720.78 192.70
concrete 75-100 0.46 432 578.88 471.74 707.62 198.72
M 30 25-50 0.45 410 578.10 490.36 735.54 184.50
50-75 0.44 438 573.78 478.30 717.44 192.72
75-100 0.43 476 547.40 468.38 702.58 204.68
M 35 25-50 0.44 465 567.30 466.86 700.29 204.60
50-75 0.42 488 550.31 465.57 698.36 204.54
75-100 0.41 496 545.60 464.26 696.38 203.36

The IndIan ConCreTe Journal | november 2019 9