Prez on pervious concrete

1. PERVIOUS OR POROUS CONCRETE
Manuj Sinh
M Tech (Structures)

2. FLOODING SITUATION IN COUNTRY AS ON DATE
VIDEOS OF FLOOD CONDITION IN INDIA
AVAILABLE ONLINE

3. BACKGROUND : WHY PERVIOUS ?
• Construction boom has taken place, cities and suburbs are constantly
expanding and have become densely populated .
• Areas with vegetation have now been replaced by infrastructure.
• Resulting in greatly disrupting the natural water cycle
• Excessive use of impervious covering poses challenge of increased runoff
volumes, bank erosions, flooding and the degradation of water quality.
• Problem pose considerable risk to the sustainable development of cities
and suburban areas.
• It s a serious matter that requires immediate attention and a viable
solution.
• Various options exists to water harvesting and ground water table
recharging is most common and prevailing in cities is one of the solution
• Other available options cant be ruled out
• Interlocking tiles.
• Porous Concrete.

4. INTRODUCTION: POROUS CONCRETE
• Special Concrete.
• Mix.
• Cementitious paste.
• Preserves.
• High porosity.
• Allows Flow.

6. DEMO ON POROUS CONCRETE
VIDEOS OF FLOOD CONDITION IN INDIA
AVAILABLE ONLINE

7. CONTENTS
• Introduction#
• Mix Proportion
• Properties
• Variation in strength and rupture.
• Environmental benefits
• Disadvantages
• Application
• Construction Demo
• Conclusion.

8. INTRODUCTION
• Same basic constituents as conventional concrete
except 15% to 30% of its volume consists of an
interconnected void.
• Mixture of Cement, Coarse aggregate and with or
without sand (Fine aggregate).
• Has enough cementitious paste to coat the coarse
aggregate
• Preserves the interconnectivity of the voids.
• Allows water to pass through the concrete.
Pervious or Porous Concrete

9. LITERATURE REVIEW
INTRODUCTION TO PERVIOUS CONCRETE
• Pervious concrete is both a pavement and a storm water mgt
tool.
• Pavement
• Used for pavement in parking lot.
• Sidewalk‐like applications.
• Occasionally used on low‐volume roads.
• Storm Water Mgt Tool.
• Allows rainwater infiltration.
• Reduces the size or eliminate the need for storm water
retention ponds .
• Eliminates the cost of curb and gutter and connecting to the
city storm sewer.
• Reduces the need for infrastructure.

10. • Pervious concrete is a reliable storm-water
management tool
• Regions without freeze/thaw cycles protected
from im-permeability,
• Not subject to frequent heavy vehicle loads.
• Ensure sufficient cement paste hydrates.
• Prevent clogging
• Ensure no structural failures ie structural
integrity
• Ensure desired workability

11. HISTORY: PERVIOUS CONCRETE
• In use since the 19th century.
• Europe: late 1800s to mid 20th century to build houses.
• In 1948, over 250,000 homes had been built in UK.
• Use incr esp after WWII- Paucity of building materials in Europe and Russia .
• In US from mid 1970’s when the constr industry considered reducing energy
costs and exploring alternatives.
• In the 1990s and early 2000s, pervious concrete was explored as a wear course
on high-speed roads in Europe and Japan. In this application, the pervious
concrete served as a noise reducer and safety measure. The pervious
concrete’s interconnected void network attenuates noise and removes water
from the vehicle wheel path, which effectively improves road safety due to
skid resistance.
• Research conducted in the United States also investigated the sound
attenuation function of pervious concrete pavements for both high-speed and
low-volume roads .
• In 2000s, research in the US focused on mix design, permeability, and
structural durability.

12. ROLE OF PERVIOUS CONCRETE IN
SUSTAINABILITY INITIATIVES
From a sustainability perspective, pervious concrete serves many purposes.
•The pervious surface allows rainwater to remain at the site on which it
falls.
•This aids in recharging local aquifers whereas storm sewer systems remove
most storm water that falls on impervious surfaces.
•Because pervious concrete is lighter in colour than typical asphalt
pavement, its use as a parking lot surface reduces the urban heat island
effect .
•Pervious concrete has also been credited with removing excess nutrients
from storm water, which reduces nutrient pollution of nearby bodies of
water.
•Because of these uses, pervious concrete is considered a sustainable
building material.
•It can assist a building owner in the earning of points for Green Building
certification GRIHA .

13. •Lack of research.
•Specific to service conditions in high altitude
environ( freeze/thaw regions).
•Maintenance.
•Rheological properties.
•Sound structural design.
•Long-term viability.
•Heterogeneous cement hydration showed the
most distresses.
PROBLEM AREAS

14. • Special type of concrete with
high porosity.
• Allows water from precipi-
tation and other sources to
pass directly through the
concrete
• The high porosity is attained
by a highly interconnected
void content.
• No fines concrete
INTRODUCTION

15. • Why do we require porous concrete?
PERVIOUS OR POROUS CONCRETE
• Reduced ground water
recharge
• Water wastage in terms of
surface runoff.
• City road Ponding.
• City Floods.

16. WORKING : PERVIOUS SYSTEM

17. Pervious Concrete Constituents
• Pervious concrete maintains its interconnected void volume because of a single
sized or narrowly graded aggregate and dense cement paste that thinly coats
each aggregate without filling the aggregate‐created voids .
• The size of the pervious concrete aggregates used for drainage are typically ¼
in. to ¾ in., and the type of aggregates typically used are crushed limestone,
granite, or gravel.
• Fine aggregates are sometimes incorporated into pervious concrete, but this
practice also decreases permeability.
• In addition to aggregate, water, and cement, admixtures such as water
reducers, set retarders, air‐entrainers and pozzolanas are added to pervious
concrete.
• As indicated by a 2004 National Ready Mixed Concrete Association (NRMCA)
report, pervious concrete mix constituents fall in the following ranges:
• Cement : 300‐600 lb/yd = 150‐300 kg/m
• Coarse Aggregate: 2,400‐2,700 lb/yd = 1200‐1350 kg/m
• Fines : 0 lb/yd = 0 kg/m
• W/Cement ratio : = 0.27 to 0.43

18. MIX PROPORTIONS

19. PROPERTIES OF PERVIOUS CONCRETE
Ser Properties Range
1. Density 1600 2000 Kg/m³
2. Void 20 35 %
3. Permeability 120 320 L/m²/min
4. Compressive
strength
3.5 28 MPa
5. Flexural
strength
1 3.8 MPa
6. Shrinkage 200x10¯⁶
7. Freeze Thaw Entrained air improves freeze
and thaw protection

20. PERVIOUS CONCRETE PROPERTIES
Strength
•Strength and material properties are determined by paste strength,
aggregate type, and volume of interconnected voids.
•Compared to conventional concretes with similar quantities of
cementitious materials, Pervious concrete exhibits.
• Lower unit weight.
• Lower modulus of elasticity.
• Lower compression, tension, flexural, and bond strengths .
• Lower shrinkage.
• Higher value of thermal insulation.
• Poisson’s ratio same.
• Strength and permeability are competing factors when designing
pervious concrete. it is difficult to separate the two because one is
dependent on the other. As strength increases, permeability decreases
and vice versa.
Strength and permeability.

21. Strength(contd..)
•Str of conventional concrete is determined by its w/c ratio,
pervious concrete str is controlled by both the w/c ratio and unit
weight.
•For a given cement content, narrow rg of w/c ratios that
produced the highest compressive strengths .
•Items that incr the unit weight of pervious concrete such as
smaller agg size (3/8”), inclusion of sand in the mix and an incr in
cement content , typically incr the comp, tensile, and flexural str of
pervious concrete, but they also decr the permeability.
•Certain polymers were found to enhance pervious concrete str by
improving the bond between cement and agg.
•Addition of fiber reinf to pervious concrete shows both incr and
no affect on the allowable bending strength.
•Quality and shape of agg rather than type of agg affects the
allowable strengths.

22. Permeability.
•Permeability of pervious concrete describes the storm water
infiltration capacity per unit of time.
•Pervious concrete’s infiltration capacity is dependent on the
volume of interconnected voids and is measured as the
amount of water that can pass per unit of time.
•The ability of pervious concrete to infiltrate the required
amount of water depends on the initial design and the amount
of foreign material that is deposited and consolidated within
the void structure over time.
•Pervious concrete’s void ratio is somewhat dependent on the
compaction of pervious concrete, and compaction is
dependent on the aggregate size and shape and the method of
compaction or consolidation.

23. ASTM STANDARD FOR MEASURING THE INTERCONNECTED
VOID RATIO
• Until 2008, there was no ASTM standard for measuring the
interconnected void ratio of pervious concrete so more than one
method was described in the literature.
• One of the most referenced methods for determining void ratio of
pervious concrete is an equation proposed by Park and Tia :
A = 1 – {[(W2 – W1)/ρw]/V1} * 100 (%)
• A = total void ratio of the pervious concrete (in percent)
• W1 = underwater weight of the cylindrical specimen (kg)
• W2 = 24‐hour air dried weight of the cylindrical specimen (kg)
• V1 = specimen volume (mm3)
• ρw = density of water (kg/mm3)

24. MEASURE IN SITU:PERMEABILITY OF PERVIOUS CONCRETE
• The permeability of pervious concrete can be tested in the field
or in the lab with samples taken from the field, or in the lab with
lab‐produced samples.
• Principle : Permeablility was measured by the time it took for a
known amount of water to infiltrate the pervious concrete.
• Device used : Double ring infiltro‐meter.
• Bottom of the infiltrometer is sealed to the pervious concrete
with foam around the base and putty‐sealed to the concrete
and fed water by an attached plastic jar .
• A unique feature of the double ring infiltro‐meter was that it
limited lateral flow through the pervious concrete whereas the
other tests did not.

25. A DOUBLE RING INFILTRO‐METER

26. MEASURE IN LAB :PERMEABILITY OF PERVIOUS CONCRETE
• The device most often used for laboratory measurement of
pervious concrete permeability was the constant head permea‐
meter.
• The instrument, while different at each laboratory, performed a
similar test: the sides of the pervious concrete sample were
sealed, a head (height) of water was maintained above the top end
of the sample, and a volume of water that exited the lower end of
the cylinder was collected for a specified amount of time.
• Once the water was collected, its volume was measured and
compared to the amount of time it took to travel through the
sample .
• A variation of this test involved a falling head permeameter
instead of a constant head permeameter.

27. CONSTANT/FALLING HEAD PERMEAMETER.
• Flow is steady , Sample in a right circular cylinder with length =L and Area =A.
• Constant head difference is = h applied across the sample producing a flow rate Q.
• Darcy Law.
Q=k A h /L or k = QL/Ah

28. CLOGGING OF THE INTERCONNECTED VOIDS
• Clogging of the interconnected voids is another aspect that limits the
permeability of pervious concrete over time.
• Pervious concrete becomes semi‐impermeable to impermeable when
material fines such as soil, grass clippings, leaves, acorns, and sand.
• Over time, the fines consolidate within the pervious concrete void
structure and limit or completely impede permeability.
• Ideally, sources of fines are either eliminated or diverted away from the
pervious concrete, or, at least, the quantity of fines that reach the
pervious concrete should be minimized by vegetation on surrounding
landscape.
• Since fines enter the pervious concrete from the surface, it is reasonable
to deduce that pervious concrete impermeability begins at the surface.
• Delatte hypothesized that clogging begins at the bottom and progresses
towards the top.

29. • Pressure washing and vacuuming were the two
methods suggested to maintain the permeability of
pervious concrete.
• The effectiveness of permeability remediation was
often measured with a permeameter both before and
after the remediation attempt
• Maintenance using backflushing pervious concrete.
Approx 0.5 psi pressure could force clogging material
out.

30. RELATIONSHIP BETWEEN AGE AND COMP STRENGTH
Age in Months
Compressive
strength psi
Coarse aggregate: Crushed Basalt
Water Cement ratio: 0.43
Aggregate Cement ratio 8:1
10.99
9.62
8.24
6.36
5.49
4.12
2.75
1.37
0
Compressive
strength
KN/m²

31. RELATIONSHIP BETWEEN AGE AND COMP STRENGTH
Age in Months
Compressive
strength, psi
Coarse aggregate: Crushed Basalt
Water Cement ratio: 0.43
Aggregate Cement ratio 8:1
MN/m²
3.43
2.75
2.06
1.37
0.69
0
(Specimen size 18 x 9 x 4.25 inch slabs)

32. Relationship Between Age and
Modulous of Rupture

33. ENVIRONMENTAL BENEFITS
• Reduces storm water runoff.
• Eliminates need of storm water mgt practices.
• Replenishes water tables and aquifers.
• Allows for more efficient land development.
• Minimizes flash flooding and standing water.
• Prevents polluted water into streams.
• Mitigates surface pollutants.

34. DISADVANTAGES
• Runoff from adjacent areas onto pervious concrete
needs to be prevented.
• The parking areas are generally limited to auto
parking and occasional trucks.
• If reinforcement is required, epoxy coated bars
should be used.
• Concrete is variable in permeability; over vibration
significantly reduces permeability.
• It is still a new material that requires acceptance
from cities and states.

35. APPLICATIONS
• Low vol pavements
• Pervious pavement for parking lots.
• Cement Concrete Playing Courts.
• Alleys and driveways.
• Trees gates in sidewalk .
• Swimming pool decks.
• Greenhouse floors.
• Well Linings.

36. PERVIOUS CONCRETE PAVEMENT CONSTRUCTION AND
DESIGN
Pervious Concrete Construction
•The most common way that pervious concrete pavement is constr is
as given below and illustrated in the photos.
• Base Layer Installation.
• Placing Pervious Concrete
• Finishing Pervious Concrete
• Edging
• Jointing Pervious Concrete.
• Curing
•It is important to note that jointing of pervious concrete can be
accomplished either by cutting joints into plastic concrete with a
circular blade attached to a heavy steel roller or by saw cutting joints
into hardened concrete.

37. Base Layer Installation.
•On top of sandy soil and
pervious fabric that separates the
rock and sand layers.
Placing Pervious Concrete
•Placing with a vibratory
screed roller.

38. Edging
•Edging pervious concrete to
ensure adequate compaction at
edges.
Finishing Pervious Concrete
•Finishing with a weighted steel
roller.

39. Curing
•pervious concrete beneath a
polyethylene plastic sheet.
Jointing Pervious Concrete.
•Note that the joint in the
pervious concrete matches the
location of the joint in the
adjacent conventional concrete.

40. CONSTRUCTION DEMO
Video to play

41. CURING: CRITICAL PROCESS
• The effect of curing on pervious concrete was often measured in
terms of the decrease in compressive strength compared to either
wet cured pervious concrete or pervious concrete cured for seven
days beneath a plastic sheet.
• A paper dated 1952 reported that no‐fines concrete made with a
dense, non‐absorptive aggregate and cured in air only reached 43%
of the compressive strength of a similar no‐fines concrete moist
cured for seven days .
• Another paper showed that the strengths of air‐cured pervious
concrete at 7, 28, and 91 days reached 54%, 78%, and 77% of the
specimens cured in 80% relative humidity.
• In addition, it was observed that the air‐cured samples failed
because the cement paste failed to hold the aggregate particles
together, and it was presumed that the lower strength was due to
the incomplete hydration of the cement.

42. • Curing ultimately affects pervious concrete because it affects the
cement paste pore size vol and distribution. Tech, as the w/c ratio
decr, the microscopic pores within the paste decr both in dia and vol.
• The fewer pores there are in concrete paste, the stronger it is.
However, as the w/c ratio decr, the amt of cement that can be
hydrated also decr. If the w/c ratio is too low or if too much water is
allowed to evaporate from the plastic pervious concrete, the lack of
cement hydration will render the concrete weak.
• In order to achieve the smaller pore size and vol adequate moisture
must be available to the paste during curing.
• Other research on pervious concrete curing reports that drying is
more serious for no fines concrete than for conventional concrete
because dry paste fails to hold the aggregate particles together.
• The NRMCA recommends that pervious concrete be covered with a
polyethylene plastic sheet as soon as possible following placement
and that curing must continue for a min of seven days with
occasional rewetting if the pervious surface shows signs of drying.

43. CONTRACTOR QUALIFICATION
• In the introduction to a paper that reviewed case studies of pervious
concrete in the Southeastern United States, it was stated that, “It
should be stressed that contractor qualifications by certification is
one of the most important practices related to the installation of
pervious concrete” .
• One of the reasons why experience and training are important for
contractors and ready‐mix suppliers is because plastic pervious
concrete cannot be evaluated by familiar conventional concrete
standards such as the slump test or air test.
• In practice, visual inspection and experienced contractors confirm a
good mix.
• Designer knowledge and experience are also important so they
understand when it is appropriate to specify pervious concrete and
to require an experienced contractor.

44. PERVIOUS CONCRETE DESIGN
• Design parameters of pervious concrete pavements such as thickness
and joint spacing are similar to those for conventional concrete.
• The loc and environmental conditions in which pervious concrete is
appropriate are restricted.
• Thickness Design Methods determined by AASHTO and Portland Cement
Association (PCA) were appropriate for pervious concrete pavements .
• American Concrete Institute Specification for Pervious Concrete
Pavement indicates that jointing, when not specified, must not exceed
twenty ft., and also specifies jointing angle, joint alignment, joint depth,
and isolation/contraction joint requirements.
• ACI also specifies that the larger horizontal dimension of a pervious
concrete panel shall not exceed 125% of the smaller dimension.
• Pervious concretes require deep, permeable soils, restricted traffic, and
restricted adjacent land uses [2].

45. SUMMARY
• Pervious concrete is concrete with a network of voids that allow
liquid to pass through the concrete. These voids are typically 15%‐
35% of the concrete’s total volume .
• The voids are formed by a combination of gap‐graded coarse
aggregate and a lack of paste volume to fill all of the void space
created by the gap graded aggregate. T
• The cement paste must be of the consistency that allows it to coat
each aggregate and remain around the aggregates without
slumping off.
• The course aggregate size in pervious concretes is typically 3/8 ±
1/8 in. Fine aggregate is often eliminated because it decreases the
void volume resulting in reduced permeability.
• Pervious concrete’s water to cement ratio is characteristically
below 0.30.

46. • The allowable compression, flexural, and tensile stresses of
pervious concrete are less than those of a concrete made with a
standard gradation of coarse and fine aggregates and a similar
quantity of cementitious materials.
• Pervious concrete is a dual‐purpose building material that must
satisfy specifications both as a stormwater runoff best
management practice and as a pavement.
• To these ends, its design requires a balance of permeability,
strength, and durability.
• Pervious concrete is primarily used for storm water infiltration and
is typically as pavement in parking lots, patios, sidewalks, low‐
volume roads, parking bays, and alleys. Pervious concrete has also
been labelled as a sustainable building tool for decreasing the
amount of impermeable surface on a building site after new
construction or renovation and is credited with decreasing noise
generated by tyre pavement interaction on high‐speed roadways.

47. CONCLUSION

48. PERVIOUS CONCRETE SURFACE DISTRESSES

49. DISTRESSES IN PERVIOUS CONCRETE
• Primary Distresses In
• Impermeability,
• Raveling
•Surface Raveling.
•Deep Raveling.
• Cracking.

50. • During rains the storm water remained on the concrete’s
surface or it ran off the surface without infiltration into
pervious concrete pavement.
• The concrete is severely clogged with debris/ waste mtrl.
• Reasons/Causes.
•Flow of storm water over the pavement surface from
adjascent areas/runoff results in soil erosion and grass
clippings being was directed towards the pavement
surfaces.
•Approaches and exits to other dusty roads from pervious
concrete pavement.
•Proximity to beaches/lakes results in sand carriage.
•Clogging with debris primarily from overhanging tree.
IMPERMEABILITY

51. RAVELING
• Raveling/Spalling occurs when the aggregates de‐bond
from the cement paste.
• Surface distress.
• Reasons/Causes.
– Extreme temperatures at the time of placement.
– A dry batch.
– Over finishing .
• Place of Occurance. Surface and deep raveling
occurred in both the bulk concrete matrix and at
discontinuities in the pervious concrete such as at
joints, cracks, edges, and inclusions.

52. Surface Ravel
•Surface ravel is raveling of the
top 2‐3 aggregate layers.
•The causes of surface ravel
appeared to be shear stress from
turning veh tires and drying
shrinkage.
Deep Ravel
•Deep ravel is raveling of multiple
agg layers, and it appeared as an
area of loose agg.
•Begins at discontinuities such as
joints, cracks, edges, or inclusions
which aggravated the distress.

53. Joint Ravel
•Raveling occurring at joints.
Edge Ravel
•Edge ravel occurs at edges in
pervious concrete pavement.

54. Crack Ravel
•Shrinkage or structural cracking
showed crack ravel.
•Severity of the crack raveling is
gen minimal.
•Crack raveling did not propagate
as surface or deep ravel.
Inclusion Ravel
•Inclusion are objects that disrupted
the pervious concrete surface eg.
parking lot light poles as the paving
procedure is disrupted.
•Concrete around the inclusions is
compacted by hand.
•Incr the time and water loss before
covering.

55. CRACKING
• Joint spacing or effective width of the pervious concretes
slabs is kept around 12 ft or less to prevent shrinkage
cracking.
• Spacing accordingly.
• Minimum joints to avoid discontinuities in pervious concrete
as they are susceptible to raveling.
• Reasons.
• Stresses created by unavoidable large vehicle loads eg.
maintenance trucks, garbage truck etc.
• Structural cracks due to settlement or erosion of
pavements base or subgrade materials.
• Multiple cracks may be caused by differential frost heave.

56. • Pervious concrete typically performs as a dual‐role infrastructure.
It has to function both as a stormwater runoff management tool
and as a concrete pavement.
• Primary distresses observed on the surfaces of the pervious
concrete pavements and these were impermeability, raveling, and
cracking.
• impermeability was caused by a large quantity of organic matter
on the surface that was consolidated into the pervious concrete
voids by vehicle tires.
• Coarser fines, such as sand, reduced but did not eliminate
permeability
• Surface, joint, edge, crack, and inclusion ravel typically had more
of an effect on appearance than on the structural integrity of the
pervious concrete. Surface ravel does not necessarily threaten the
long‐term viability of the pervious concrete as it
CONCLUSION

57. • Distress in the top aggregate layer is similar to the types of
abrasion damage seen in conventional concrete that occur from
plowing snow.
• Deep raveling, besides being unsightly, contributes to pervious
concrete failure and could cause damage to vehicles if the raveled
contents were pushed out of the pavement by tires or sweeping,
effectively leaving a pot hole.
• Additionally, if the pervious concrete serves as the pavement
material for a sidewalk or path, deep raveling would make wheeled
recreation, such as biking, rollerblading, or pushing a stroller,
difficult.
• Cracks showed that they were susceptible to raveling, which, in the
case of driving surfaces, could contribute to a rough pavement.

58. Loc Jaipur, Gandhi nagar rly stn Parking lot
Key Pers Prof. Prithvi Kandhal, designed and supervised construction, also
worked at Franklin Institute of Philadelphia (USA) in developing
porous asphalt pavement technology
Constr by Jaipur Development Authority 2012
Characteristics open‐graded stone bed, 225 mm thick, Allows water percolation
Evap Losses Evaporation loss is minimal. Water infiltration capacity is higher
(0.8) than that of regular cropped areas (0.3).
Addl Adv Integ of rooftop rainwater harvesting systems of adjacent bldgs
Cost Cost per sqm is 18% higheras for conventional surfacing.
Problem Areas Heaps of agg and other constr mtrl stacked on it were choking it.
Life if maintained properly, can last more than 20 years.
Continuous
Maint
Parking lot worked efficiently during two monsoons but the JDA
has lost interest in maintaining it.
ASPHALT POROUS CONCRETE PARKING LOT IN JAIPUR: DETAILS

59. ASPHALT POROUS CONCRETE PARKING LOT IN JAIPUR
IMAGE: PROF. KANDHAL