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