1. READYMIX INDUSTRY
There are two main components in asphalt concrete: 1) the asphalt cement, or glue, and 2) the aggregates.

2. READY MIX INDUSTRY
(BASED ON ASTM C94)
BASIS OF PURCHASE
BATCHING
MIXING
TRANSPORTING

3. BASIS OF PURCHASE:
IN ABSENCE OF A DESIGNATED SPECIFICATION, A PURCHASER MUST REQUEST:
DESIGNATED SIZE OR SIZES OF AGGREGATE
SLUMP REQUIRED
AIR ENTRAINMENT – AIR TEST AT PLACEMENT
THE CHOICE OF OPTION A,B,OR C FOR
PROPORTIONING THE MIX
DRY UNIT WEIGHT FOR YIELD TEST
(FOR STRUCTURAL LIGHTWEIGHT CONCRETE)

4. BASIS OF PURCHASE:
OPTION A OR C (ASTM C94)
MANUFACTURER ASSUMES FULL RESPONSIBILITY
FOR SELECTING THE MIX PROPORTIONS
PURCHASE HAS TO DECIDE ON THE 28 DAY
STRENGTH
OPTION B (IN ADDITION)
PURCHASE MUST SPECIFY MIN. ALLOWABLE CEMENT
CONTENT TO BE USED IN THE MIX DESIGN
DESIGNATED SIZE OR SIZES OF AGGREGATE
SLUMP REQUIRED
AIR ENTRAINMENT – AIR TEST AT PLACEMENT
OVEN DRY WEIGHT FOR YIELD TEST (UNIT DRY WT.)

5. BASIS OF PURCHASE:
OPTION B continued (ASTM C94)
PURCHASER ASSUMING THE RESPONSIBILITY FOR
PROPORTIONING THE CONCRETE MIXTURE
SPECIFY CEMENT CONTENT PER CY
SPECIFY WATER CONTENT PER CY
THE TYPE AND DOSAGE FOR ALL THE ADMIXTURE
SIZE OF AGGREGATE AND SLUMP REQUIRED

6. BATCHING
MEASURED BY WEIGHT
CEMENT
FINE AND COARSE AGGREGATE
FLYASH AND POZZOLANS
MEASURED BY WEIGHT AND VOLUME
WATER
ADMIXTURE

7. BATCHING
BATCH PLANTS
HOPPER CAN WEIGH CUMULATIVELY OR
INDIVIDUALLY
AGGREGATES WATER CONTENT HAS TO BE
DETERMINED
TOTAL MOISTURE =WATER CONTENT
TOTAL WET WT. = DRY AGG + WT. OF MOISTURE
POWDERED ADMIXTURE ARE MEASURED BY WEIGHT
LIQUID ADMIXTURE ARE MEASURED BY WEIGHT OR
VOLUME

8. BATCHING
BATCH PLANTS
WEIGH BATCHER
TRUCK MIXERS
COARSE AGG SHOULD BE DISCHARGED BEFORE
OTHER INGREDIENTS
ALL SCALES HAVE TO BE CALIBRATED

9. SHOULD NOT EXCEED 63% OF THE DRUM VOLUME
MIXING
MIXERS AND AGITATORS
STATIONARY MIXERS
I.E. TILTING DRUM MIXER DISCHARGES WHILE TILTING
THE MIXING, IN OPPOSE TO A NON-TILTING MIXER
TRUCK MIXERS (AVG CAPACITY IS 8-9 YDS)
Note the cliché – “Give me the whole nine yards!”
FRONT DISCHARGE
REAR DISCHARGE
SHOULD NOT EXCEED 63% OF THE DRUM VOLUME
AGITATORS (MAYBE TRUCK MIXERS OR AGITATORS)
MUST BE ABLE TO DELIVER THOROUGHLY MIX
CONCRETE TO THE JOBSITE
SHOULD NOT EXCEED 80% OF THE DRUM VOLUME

10. MIXING
UNIFORMITY TEST
SAMPLES MUST HAVE THE SAME:
SLUMP- SLUMP TEST
UNIT WT. – YIELD TEST
AIR CONTENT – AIR METER OR AIR TEST
STRENGTH – COMPRESSION TEST

11. MIXING
MIXING AND DELIVERY
CENTRAL MIX – CONCRETE THAT IS MIXED COMPLETELY IN A STATIONARY MIXER
SHRINK MIX- CONCRETE THAT IS FIRST PARTIALLY MIXED IN A STATIONARY MIXER, AND THEN MIXED COMPLETELY IN A TRUCK MIXER
TRUCK MIX –CONCRETE THAT IS COMPLETELY MIXED IN A TRUCK MIXER, REVOLUTIONS AT THE MIXING SPEED

12. MIXING
NON-AGITATING MIXING
REQUIRES SLUMP TEST
USED FOR SHORTER HAULS

13. TRANSPORTING
JOB SITE CONTROL
NO ADDITIONAL WATER CAN BE ADDED EXCEPT IF SLUMP DOES NOT REACH SPECIFIED SPEC. AND THE WATER CEMENT RATIO IS NOT INCREASED
SHRINK MIX- CONCRETE THAT IS FIRST PARTIALLY MIXED IN A STATIONARY MIXER, AND THEN MIXED COMPLETELY IN A TRUCK MIXER
TRUCK MIX –CONCRETE THAT IS COMPLETELY MIXED IN A TRUCK MIXER, REVOLUTIONS AT THE MIXING SPEED

14. TRANSPORTING INSPECTION AT THE JOBSITE
CONCRETE MUST BE TESTED FOR SLUMP, AIR CONTENT, AND
STRENGTH
ACI CERTIFICATION FOR CONCRETE FIELD TESTING TECHNICIAN
– GRADE LEVEL I
ONE STRENGTH TEST IS PREPARED FOR EVERY 150 CY AND AT
LEAST ONE FOR EACH DAY THE CONCRETE IS DELIVERED OR FOR EACH CLASS OF CONCRETE (I.E. CLASS A,B OR C )
AT LEAST THREE STRENGTH TEST SHOULD BE MADE AND
AVERAGE
I.E. FOR A 4000 PSI CONCRETE
THREE SAMPLES GIVES AN AVERAGE 4100
AND NONE OF THEM ARE LESS THAN 500 PSI BELOW THE SPECIFY STRENGTH