Transcript md sha pervious concrete specifications

Review of Maryland
SHA Specification
for
Portland Cement Concrete
Permeable Pavement
System
Maintenance
Freeze Thaw Durability
Abrasion Resistance
Strength
The American Concrete Institute Committee Report ACI 522R-Pervious
Concrete, Chapter 7.2.2 states:
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“Guidance
for structural design of conventional concrete
pavements is provided in ACI 330R for parking lots and in
ACI 325.12R for streets and roads. These documents cover
many different aspects of paving design. The structural
design recommendations in these documents, however,
are not necessarily applicable for use with pervious
pavement. As there are no standardized test methods
for strength of pervious concrete, design and
specification by strength should be avoided”.
Table 902A
ACI 522R-10 R
Report on
Pervious
Concrete
Table 902A
Testing Fresh Density
ASTM C1688 Density and Void
Content of Freshly Mixed Pervious
Concrete
0.25 ft3 measure
(standard air pot)
Standard Proctor
Hammer
Example
Portland cement…….……...600 pcy
Coarse aggregate*…..…...2,670 pcy (ssd)
Water………………… …..180 pcy
Total Weight…………......3,450 pcy
*b/b 0 = 1.00 Dry rodded unit weight = 98 pcf
Design plastic unit weight = 3,450/27 = 128 pcf
Acceptance 128 +/- 5 pcf
Design air-free unit weight = 163 pcf
Calculated void content = (163-127)/163 = 22% > 15%
Fill in two equal layers
1st lift – 20 drops
2nd lift – 10 drops
Refill / 10 more drops
Density = 31.95 lb / 0.25 ft3 = 128 lb/ft3
Permeable Pavement System
Materials
Excavation
The System
Stone Base
The Pervious Concrete
Monitoring Equipment
Contractor Qualifications
Test Panels
Thickness, Density, Infiltration
ASTM C1701 Infiltration Rate as a
Function of ASTM C1688 Void
Content
Kevern, J.T, Montgomery J
Plus or minus 5
ASTM C 1701 Infiltration
400 per hour
Measuring In Place Infiltration
• ASTM C1701
• Infiltration
Rate of In
Place
Pervious
Concrete
Test Equipment
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Infiltration Ring – 12 +/- ½ in.
Scale
Container – 5 gallons
Stop watch
Plumbers Putty
Water
Test Location
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3 test for up to 25,000 sft
Additional test for each 10,000 sft
Minimum 3 ft between test location
No standing water
Do not test within 25 hours of rain
Questions / Comments