DEVELOPMENT OF SAWDUST CONCRETE FOR BLOCK MAKING
Dr. R. Sri RavindrarajahCentre for Infrastructure Research,
University of Technology, Sydney, Australia
Chistopher Carrolland
Nick AppleyardCivil Engineers, Sydney, Australia
SAWDUST
RADIATA PINE
SAWDUST VARIABILITY
• PARTCLE SIZE AND SHAPE
• CHEMICAL COMPOSITION
• DENSITY
• COLOUR
SAWDUST USAGE
• ABUNDANCE IN TROPICAL COUNTRIES
• WASTE MATERIAL FROM TIMBER SAWING
• LIMITED USE AS FUEL FOR COOKING
• DISPOSAL METHOD: OPEN BURNING
PROBLEMS RELATED TO THE USE OF SAWDUST IN CONCRETE
• AFFECT THE SETTING AND HARDENING OF CONCRETE
• PRE-TREATMENT SUCH AS WASHING
• MIXING DIFFICULTY
LIGHTWEIGHT MATERIALS USED IN CONCRETE
• AIR VOIDS
• EXPANDED POLYSTYRENE BEAD
• SAWDUST
• EXPANDED CLAY, SHALE
• NATURAL LIGHTWEIGHT AGGREGATES
PURPOSES OF THIS STUDY
• TO STUDY THE ENGINEERING PROPERTIES OF SAWDUST CONCRETE
• TO DEVELOP AN OPTIMUM MIX COMPOSITION FOR BLOCK-MAKING (OVER 12.5 MPa )
• TO DEVELOP FUTURE RESEARCH NEEDS
SAWDUST CONCRETE
• PORTLAND CEMENT (ORDINARY)
• FLY ASH (LOW-CALCIUM)
• NATURAL SAND
• SAWDUST (WITHOUT PRETREATMENT)
• WATER
• CALCIUM CHLORIDE (TO ACCELERATE SETTING)
• LIME (TO INCREASE THE ALKALINITY)
REFERENCE CONCRETE
• CEMENT 34%
• FLY ASH 6%
• SAND 12%
• SAWDUST (PINE) 3%
• CALCIUM CHLORIDE 2%
• LIME 3%
• WATER 41%
• WATER/[CEMENT + FLY ASH] 0.34
DETERMINATION OF OPTIMUM SAWDUST CONTENT
• WATER/[CEMENT + FLY ASH] = 0.34
• SAWDUST CONTENT (7 MIXES)– 3 %, 4 %, 5 %, 7 %,
– 8 %, 10 % & 12 %
DETERMINATION OF OPTIMUM WATER TO BINDER RATIO
• WATER/[CEMENT + FLY ASH]– 0.32, 0.35, 0.40, 0.46, 0.51, 0.57
• SAWDUST CONTENT (18 MIXES)– 8 %, 10 % & 12 %
DETERMINATION OF OPTIMUM CALICUM CHLORIDE CONTENT
• WATER/[CEMENT + FLY ASH]– 0.40, 0.46, 0.51
• SAWDUST CONTENT (9 MIXES)– 8%, 10% & 12%
• CALCIUM CHLORIDE CONTENT– 0%, 2%, 4%
BATCHING SEQUENCE
• SAND
• SAWDUST
• FLY ASH
• HALF OF THE MIXING WATER
• CEMENT, LIME, CALCIUM CHLORIDE
• REST OF THE MIXING WATER
01020304050
2 4 6 8 10 12 14
Sawdust Content (%)
7-da
y C
omp.
Str
. (M
Pa)
0
5
1015
20
25
30
0.30 0.35 0.40 0.45 0.50 0.55 0.60
Water/(Cement + Fly Ash)
7-d
ay C
omp.
Str
. (M
Pa)
Sawdust content (%)
8%
10%
12%
0
10
20
30
40
1400 1500 1600 1700 1800 1900 2000
Wet Density (kg/m3)
Com
p. S
tren
gth
(MP
a)
1000
1200
1400
1600
1800
2000
2 4 6 8 10 12 14
Sawdust Content (%)
Wet
den
sity
(kg
/m3
)
0
10
20
30
40
0 5 10 15 20 25 30
Age (Days)
Com
p. S
tr. (
MP
a) Calcium Chloride 2%
4%0%
CONCLUSIONS
• BATCHING SEQUENCE INFLUENCES THE SAWDUST CONCRETE PROPERTIES
• SAWDUST 12% BY VOLUME; 2% CALCIUM CHLORIDE, AND 0.51 (WATER/CEMENT + FLY ASH) PRODUCED THE DENSITY OF 1520 kg/m3 WITH THE 28-DAY STRENGTH OF 16.5 MPa
CONCLUSIONS
• SAWDUST IS AN IDEAL FILLER MATERIAL TO PRODUCE LIGHTWEIGHT CONCRETE BLOCKS
• OPTIMUM MIX PROPORTIONS MAY DEPEND ON SAWDUST TYPE
POTENTIAL APPLICATIONS
• LOAD/NON-LOAD BEARING BLOCKS
• NOISE BARRIERS
• PAVING BLOCKS
• WALL PANELS
• FLOOR PANELS
• PERMANENT FORMWORK
FUTURE RESEARCH NEEDS
• LIGHTWEIGHT CONCRETE BLOCKS SHOULD BE STUDIED FOR THE FOLLOWING PROPERTIES
– VOLUME STABILITY RELATED TO MOISTURE AND LOAD
– FIRE RESISTANCE
– INSULATION PROPERTIES
– TENSILE AND ELASTIC PROPERTIES
FUTURE RESEARCH NEEDS
• REMOVAL OF LIME FROM THE MIX
• INCLUSION OF COARSE AGGREGATE
• MOISTURE CONDITION OF SAW DUST
• FIRE RESISTANCE
• APPLYING CASTING PRESSURE
