Recycled Concrete Aggregate(RCA) used in subbase

1

EXPERIMENTAL INVESTIGATION ON CEMENT STABILIZED RECYCLED CONCRETE AGGREGATS AS SUB-BASE MATERIAL

BYSHIVUNAIKA B

M.E( HIGHWAY ENGINEERING),UVCE Bangalore.

2

INTRODUCTION• The focus towards conservation of aggregate is

based upon possibility of using waste and milled material in place of fresh aggregates.

• Construction and demolition waste is generated whenever any construction/demolition activity takes place, such as, building, roads, bridges, fly over, remodelling etc.

• These wastes are heavy, having high density, often bulky and occupy considerable storage space either on the road or communal waste bin.

3

• It is estimated that the construction industry in India generates about 10-12 million tons of waste annually.

• 750 million cu.m. of aggregates would be required for achieving the targets of the road sector.

• Recycling of concrete and masonry waste is being done abroad like U.K., USA, France, Denmark, Germany and Japan.

• To utilize large volumes of construction and demolition debris, the minimum standards set by AASHTO, as well as the local specifications, must be met

CONT……

4

Advantages of Recycled Concrete Aggregate (RCA)

• Lower costs• Lower utilization of Virgin aggregate which are becoming

scarce• Reduced land-filling• Reduced energy consumptions by eliminating fuel

consumptions required for Land-filling trips• Faster construction if in-place recycling methods are

employed.• Recycled concrete can also be used in landscape settings.• This is used as the foundation for a roadway pavement

and in the underlying layer that forms a structural foundation for paving.

5

Disadvantages of Recycled Concrete Aggregate (RCA)

• Lack of codes, specifications, standards and guidelines

• Water absorption property of aggregate is high.• Demolished concrete contains mortar which

creates dust during the crushing process and causes air pollution around the demolition area.

• The water from washing RCA may contain a high pH value due to the alkaline nature of concrete.

• Recycled materials are of lower quality than virgin aggregate.

6

Objectives of Study• To design Recycled Concrete Aggregate (RCA) mix for sub-

base course.• To determine the basic property of sub-base material as

per MORT&H (V revision).• To study the Compaction characteristics of RCA material

stabilized by varying dosages of 0%, 1%, 3%, 4% and 5% of Portland cement by weight of RCA mix.

• To study the Unconfined Compressive Strength characteristics of RCA material stabilized with 3%, 4% and 5% dosage of Portland cement by weight of RCA mix, cured for 3, 7 and 28 days.

7

CONT…

• To study the CBR characteristics of RCA material stabilized by varying the dosages of 3%, 4% and 5% Portland cement by weight of RCA mix.

• To study the Permeability of RCA mix stabilized with 3%, 4% and 5% dosage of Portland cement by weight of RCA mix cured for 3, 7 and 28days.

8

Production process of Recycled Concrete Aggregate (RCA)

Feed reception

Separation of Concrete and bricks

9

Size reduction using impact crusher

Feed Conveyor

Screening

10

Washing & Contamination Removal

Fines Recovery

11

Water Treatment

Filter Press

12

Materials used • Recycled concrete aggregate (RCA)• Water• Portland cement(Grade-43)

The fine aggregate and coarse aggregate of RCA material

13

Tests on RCA Material• Sieve analysis• Specific Gravity Test • Water absorption• Wet Aggregate impact value• Ten Percent Fines Test• Proctor compaction• UCS test (unconfined compressive strength)• CBR test• Permeability Test

14

Sieve analysis of RCA material• Sieve analysis helps to determine the particle size

distribution of the coarse and fine aggregatesTable 3.1 Sieve Analysis of RCA Material

IS sieve size, (mm)

Weight of retained, (g)

Cumulative weight retained,(g)

Cumulative % retained

Cumulative % passing (Obtained

gradation)

Requirement as per MORT&H(V revision) Table 400-1, Grade-II

Upper limit ( % passing)

Lower limit( % passing)

53 0 0 0 100 100 100

26.5 40 40 2 98 100 70

9.5 300 340 17 83 80 50

4.75 540 880 44 56 65 40

2.36 980 1860 93 7 50 30

0.425 80 1940 97 3 15 10

0.075 60 2000 100 0 5 0

15

Figure 3.2 Grain size distribution curve of RCA material

0.01 0.1 1 10 1000

10

20

30

40

50

60

70

80

90

100

obtained grain size dis-ribustion curve

Upper limit grain size distribution curve

Lower limit grain size distribution curve

Sieve size, mm

% P

assin

g

Table 3.2 Physical properties test results of RCA material

16

Description Tests Test resultObtained

Requirements as per Table 400-2 of MORT&H (V revision)

Specifications

Aggregate specific Gravity

Coarse Aggregate 2.33 -

Fine aggregate 2.40 -

Water absorption (%) 2.50 -

Wet Aggregate impact value (%) 36.48 40 Max.

Ten percent fines value(kN) 71 50 Min.

Liquid limit Non plastic 25 Max.

Plasticity index Non plastic 6 Max.

17

Portland cement• In this study cement is used as binder material. The

RCA material is non-cohesive in nature, so stabilize the RCA mix with varying dosage of cement such as 1%, 3% 4% and 5% to improve the cohesive property of mix.

Specific Gravity Test – The specific gravity of a Portland cement is

considered to be a measure quality of the Portland cement and it was found to be 3.06.

18

GRADATION OF RCA Material The Gradation results of RCA materials are fallowing Grade-II (Table 400-1) as per MORT&H (V revision) shown in Table 3.3; Figure 3.4 presents the gradation curve of the RCA material.

Table 3.3 Gradation of RCA Material

Sieve size, mmAdopted Gradation

(upper limit)

Requirement as per MORT&H(v revision) Table 400-1, Grade-II

% Passing % Passing53.0 100.0 10026.5 100.0 70-1009.50 80.0 50-804.75 65.0 40-652.36 50.0 30-50

0.425 15.0 10-150.075 5.0 0-5

19

Figure 3.4 Gradation curve of RCA material

0.01 0.1 1 10 1000

10

20

30

40

50

60

70

80

90

100

Upper limit(Adopted gardation)Lower limit

Sieve sizes, mm

% P

assin

g

20

Compaction Test on Stabilized RCA Mix

• Modified Proctor Compaction test was carried out as per IS: 2720 (part 8) on RCA mix treated with 0%, 1%, 3%, 4% and 5% of Portland cement.

• OMC and MDD were determined for various dosages of cement

• Optimum Moisture content and dry density relationship is shown in Figure 3.6 for 0%, 1%, 3%, 4% and 5% Portland cement dosages and the test results are presented in Table 3.4.

21

Procedure Required wt. of RCA mix Varying water content Mix thoroughly Inner surface of mould Smeared with oil Compact Determine the moisture content and density

22

Progress of Modified Proctor compaction test of stabilized RCA mix

23

Table 3.4 Compaction Test Results of stabilized RCA mix.

Portland cement (%)

Optimum Moisture Content (OMC)

Maximum Dry Density (MDD)

(%) (g/cc)

0 13.30 1.898

1 14.68 1.915

3 15.81 2.048

4 16.48 2.081

5 17.86 2.103

24

Figure 3.6 Moisture Content v/s Maximum Dry Density Relationship of stabilized RCA Mix

25

Strength Tests on Stabilized RCA Mix • Two strength test conducted on RCA mix

• UCS test• CBR test

26

UNCONFINED COMPRESSION TEST(UCS) The Unconfined Compressive Strength (UCS) Test is

carried out as per IS: 2720 (Part 10) on RCA mix treated with 3%, 4% and 5% of Portland cement and cured for 3,7 and 28days.

UCS test carried out on RCA mix treated with 0% and 1% of Portland cement. But the specimens are failed during demould due to lack of cohesion between the particles.

27

Procedure Obtain wt. of RCA mix and water content (MDD and

OMC) Mix thoroughly Static compaction Inner surface of mould Smeared with oil Allowed to set After extraction, the specimens are kept in a water

tank for curing.

Preparation of UCS Specimen

28

Prepared UCS specimen of stabilized RCA mix

29

Curing of UCS specimen of stabilized RCA mix

30

Testing of UCS specimen and failed UCS specimen of stabilized RCA mix

31

Test results of UCS of stabilized RCA mix.Table 3.5 The results of UCS test (stress and strain of RCA mix stabilized with

3% cement)

StrainNormal stress=P/A (kg/cm2)

3 days 7 days 28 days0.0000 0.00 0.00 0.000.0010 0.24 0.29 0.480.0020 0.41 0.71 1.400.0030 0.81 1.01 2.450.0041 1.54 1.44 3.540.0051 2.27 2.22 5.060.0061 3.00 2.95 6.870.0071 3.56 3.70 9.270.0081 4.12 4.49 12.870.0091 4.84 5.14 15.890.0102 5.32 6.01 17.020.0112 5.72 6.66 17.600.0122 6.03 7.23 17.420.0132 6.19 7.59 17.380.0142 6.26 7.26 17.350.0152 6.17 7.10 17.300.0162 6.11 7.03 17.260.0173 6.08 6.80 17.180.0183 6.03 6.73 17.1

32

Figure 3.10 The diagram of UCS test (Stress-strain diagram of RCA mix stabilized with 3% cement and cured for 3, 7 and 28days)

0.0000

0.0020

0.0040

0.0060

0.0080

0.0100

0.0120

0.0140

0.0160

0.0180

0.02000.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Stress v/s Strain

3 Days curing7 Days curing28 Days curing

Strain

Stre

ss, k

g/cm

2

33

Table 3.6 The results of UCS test (stress and strain of RCA mix stabilized with 4% cement)


3 days 7 days 28days

0.0000 0.00 0.00 0.000.0010 0.47 0.16 0.850.0020 0.91 0.76 1.990.0030 1.78 1.46 3.290.0041 3.06 2.40 4.670.0051 4.25 4.01 6.040.0061 5.41 5.65 7.290.0071 6.12 7.08 8.660.0081 6.82 8.43 10.220.0091 7.49 8.99 11.910.0102 8.07 9.57 13.630.0112 8.23 9.88 15.430.0122 8.44 10.24 17.180.0132 8.65 10.09 18.240.0142 8.89 9.86 18.840.0152 9.05 9.52 18.630.0162 9.21 9.48 18.580.0173 9.27 9.38 18.50.0183 9.32 9.13 18.42

34


0.0000

0.0020

0.0040

0.0060

0.0080

0.0100

0.0120

0.0140

0.0160

0.0180

0.02000.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Stress v/s Strain


Strain

Stre

ss, k

g/cm

2

35

Table 3.7 The results of UCS test (stress and strain of RCA mix stabilized with 5% cement)


3 days 7 days 28days0.0000 0.00 0.00 0.000.0010 0.14 0.23 0.140.0020 0.38 0.76 0.290.0030 0.58 1.22 0.650.0041 1.10 1.72 1.260.0051 1.77 2.37 1.910.0061 2.96 3.06 2.670.0071 4.21 3.83 4.250.0081 5.43 4.68 5.900.0091 6.51 5.49 7.850.0102 7.78 6.41 10.180.0112 8.70 7.61 12.420.0122 9.40 8.97 14.650.0132 9.91 10.32 17.650.0142 9.79 11.47 20.040.0152 9.71 12.57 22.320.0162 9.68 13.25 22.180.0173 9.61 13.16 22.110.0183 9.52 13.08 22.02

36


0.0000 0.0050 0.0100 0.0150 0.02000.00

5.00

10.00

15.00

20.00

25.00

Stress v/s Strain


Strain

Stre

ss, k

g/cm

2

37

Comparison of UCS values of RCA mix stabilized with 3% dosage of cement, 4% dosage of cement and 5% dosage of cement at common

days of curingTable 3.8 The results of UCS test(stress-strain values of RCA mix stabilized

with 3%, 4% and 5% dosage of cement at 3day curing)

Strain3days curing, Normal stress (kg/cm2)

3% cement 4% cement 5% cement

0.0000 0.00 0.00 0.000.0010 0.24 0.47 0.140.0020 0.41 0.91 0.380.0030 0.81 1.78 0.580.0041 1.54 3.06 1.100.0051 2.27 4.25 1.770.0061 3.00 5.41 2.960.0071 3.56 6.12 4.210.0081 4.12 6.82 5.430.0091 4.84 7.49 6.510.0102 5.32 8.07 7.780.0112 5.72 8.23 8.700.0122 6.03 8.44 9.400.0132 6.19 8.65 9.910.0142 6.26 8.89 9.790.0152 6.17 9.05 9.710.0162 6.11 9.21 9.680.0173 6.08 9.27 9.610.0183 6.03 9.32 9.52

38

Figure 3.13 The diagram of UCS test (stress v/s strain of RCA mix stabilized with 3%, 4% and 5% dosage of cement at 3days curing)

0.0000

0.0020

0.0040

0.0060

0.0080

0.0100

0.0120

0.0140

0.0160

0.0180

0.02000.00

2.00

4.00

6.00

8.00

10.00

12.00

Stress v/s Strain

3% cement4% cement5% cement

Strain

Stre

ss, k

g/cm

2

39

Table 3.9 The results of UCS test(stress-strain values of RCA mix stabilized with 3%, 4% and 5% dosage of cement at 7days curing)



0.0000 0.00 0.00 0.000.0010 0.29 0.16 0.230.0020 0.71 0.76 0.760.0030 1.01 1.46 1.220.0041 1.44 2.40 1.720.0051 2.22 4.01 2.370.0061 2.95 5.65 3.060.0071 3.70 7.08 3.830.0081 4.49 8.43 4.680.0091 5.14 8.99 5.490.0102 6.01 9.57 6.410.0112 6.66 9.88 7.610.0122 7.23 10.24 8.970.0132 7.59 10.09 10.320.0142 7.26 9.86 11.470.0152 7.10 9.52 12.570.0162 7.03 9.48 13.250.0173 6.80 9.38 13.160.0183 6.73 9.13 13.08

40

Figure 3.14 The diagram of UCS test (stress v/s strain of RCA mix stabilized with 3%, 4% and 5% dosage of cement at 7days curing)

0.0000

0.0020

0.0040

0.0060

0.0080

0.0100

0.0120

0.0140

0.0160

0.0180

0.02000.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

Stress v/s Strain


Strain

Stre

ss, k

g/cm

2

41

Table 3.10 The results of UCS test(stress-strain values of RCA mix stabilized with 3%, 4% and 5% dosage of cement at 28days curing)



0.0000 0.00 0.00 0.000.0010 0.48 0.85 0.140.0020 1.40 1.99 0.290.0030 2.45 3.29 0.650.0041 3.54 4.67 1.260.0051 5.06 6.04 1.910.0061 6.87 7.29 2.670.0071 9.27 8.66 4.250.0081 12.87 10.22 5.900.0091 15.89 11.91 7.850.0102 17.02 13.63 10.180.0112 17.60 15.43 12.420.0122 17.42 17.18 14.650.0132 17.38 18.24 17.650.0142 17.35 18.84 20.040.0152 17.30 18.63 22.320.0162 17.26 18.58 22.180.0173 17.18 18.50 22.110.0183 17.1 18.42 22.02

42

Figure 3.15 The diagram of UCS test (stress v/s strain of RCA mix stabilized with 3% , 4% and 5% dosage of cement at 28days curing)

0.0000 0.0020 0.0040 0.0060 0.0080 0.0100 0.0120 0.0140 0.0160 0.0180 0.02000.00

5.00

10.00

15.00

20.00

25.00

Stress v/s Strain


Strain

Stre

ss, k

g/cm

2

43

UCS results of stabilized RCA mix cured for different curing periods

• Figure 3.16 shows the improvement of unconfined compressive strength with increase in curing Period for stabilized RCA mix treated with 3%, 4% and 5% dosage of Portland cement and results are presented in Table 3.11.

Table 3.11 UCS test results on stabilized RCA mix

Cement Dosage (%) Curing Period (days) Unconfined Compressive

Strength (kg/cm2)

33 6.267 7.59

28 17.6

43 9.327 10.24

28 18.85

53 9.917 13.25

28 22.32

44

Figure 3.16 Curing period v/s UCS of stabilized RCA mix

0 5 10 15 20 25 300

5

10

15

20

25

Curing Period v/s UCS


Curing Period, Days

UC

S, k

g/cm

2

45

California Bearing Ratio Test (CBR)

Procedure Required wt. of RCA mix Obtain water content by OMC Mix thoroughly Inner surface of mould Smeared with oil Compact Determine the CBR value

46

Portland cement (%)

California Bearing Ratio (%)

Un-soaked condition soaked condition (4 days)

3 93 131

4 98 145

5 126 168

Table 3.12 CBR value of stabilized RCA mix at 2.5mm penetration

47

Figure 3.17 Preparation of CBR specimen of stabilized RCA mix.

Figure 3.18 Soaking the CBR specimen of stabilized RCA mix.

48

Figure 3.19 Testing of CBR specimen of stabilized RCA mix.

49

Permeability Test on RCA Mix

• Constant Head Permeameter The test were conducted varying dosage with curing day such

as 3%, 4% and 5% cement and 3, 7 and 28 days respectively. The amount of water flowing through a certain area can be

represented by coefficient of permeability represented by ‘K’ the unit of K is meter / seconds.

50

Figure 3.20 Constant head permeability test on stabilized RCA mix

51

Table 3.13 Permeability test results of stabilized RCA mix

Cement Content (%)Coefficient of Permeability (m/day)

3days curing 7days curing 28days curing

3 31.104 30.24 30.10

4 30.90 30.12 30.13

5 28.51 27.64 27.62

52

DISCUSSION

COMPACTION CHARACTERISTICS • Optimum moister content of untreated RCA mix and

RCA treated with 1%, 3%, 4% and 5% of Portland cement were found to be 13.30%, 14.68%, 15.81%, 16.48% and 17.86% and maximum dry density were found to be 1.898, 1.915, 2.048, 2.081 and 2.103 g/cc respectively.

• The increase in OMC with increase in cement content may be due to the– increase in surface area and – porous in nature.

53

UNCONFINED COMPRESSION TEST

Effect of curing period on Unconfined Compressive Strength

• The Unconfined compressive strength of RCA mix treated with 3% Portland cement and cured for 28 days is increased by 64.44% as compared to 3 days curing period.



• This increasing may be due to chemical bond develops in stabilized RCA mix by the increasing in curing period.

54

Effect of dosage of cement on Unconfined Compressive Strength Value

• Unconfined compressive strength of RCA mix treated with 5% Portland cement and cured for 3 days is increased by about 36.83% and 5.95% as compared to RCA mix treated with 3% and 4% cement.



• RCA is more sensitive to changes in cement content, increases the cement content with increases the unconfined compressive strength.

55

CALIFORNIA BEARING RATIO TEST (CBR)

• The un-soaked CBR value of stabilized RCA mix treated with 3%, 4% and 5% dosage of Portland cement were found to be 93%, 98% and 126% respectively.

• The 4 days soaked CBR value of stabilized RCA mix treated with 3%, 4% and 5% dosage of Portland cement was found to be 131%, 145% and 168% respectively.

• Good inter locking between particle• bonding action due to cement presence.

56

PERMEABILITY TEST • The coefficient of permeability of RCA mix treated with 4 and 5% of

cement and cured for 3 day is decreased by about 0.64% and 8.32% respectively as compared to RCA mix treated with 3% of cement.

• The coefficient of permeability of RCA mix treated with 4 and 5% of cement and cured for 7 day is decreased by about 0.39% and 8.59% respectively as compared to RCA mix treated with 3% of cement.

• The coefficient of permeability of RCA mix treated with 5% of cement and cured for 28 day is decreased by about 0.082% as compared to RCA mix treated with 3% and 4% of cement.

• The coefficient of permeability of RCA mix reduces, because of hydration of cement and fine particle of cement

57

CONCLUSIONS• The test results of RCA are satisfying the requirements of GSB as per

table 400-2 of MORT&H (V revision) specification.• Increase in dosage of stabilizer, increases the optimum moisture

content and dry density.• Unconfined Compressive strength of stabilized RCA mix increases

with increase in percentage of Portland cement and curing period.• The California Bearing Ratio of stabilized RCA mix treated with

Portland cement and soaked for 4 days is higher than the mix tested after treating with Portland cement.

• Permeability of stabilized RCA mix decreases with increasing percent of Portland cement and curing days.

Cost Analysis• Based on initial cost of construction the cost of 11.75m wide

granular sub-base with cement stabilized RCA mix and the cost of conventional granular sub-base was found to be Rs. 2194 per cubic meter and Rs. 2125 per cubic meter respectively.

58

SCOPE OF FUTURE WORK

• Experimental investigation on cement stabilized recycled concrete aggregate and brick aggregate as sub-base material.

• Experimental investigation on recycled concrete aggregate used as a soil stabilizer.

• Study the characteristics recycled concrete aggregate as dry lean concrete.

59

REFERENCE• Hasan T, Behnam A “An Investigation On The Using Of Cement Stabilized Recycled

Concrete And Brick In Pavement Layers” Indian J.Sci.Res.ISSN:2250-0138(Online) 1(2) : 297-306, 2014.

• Ahmed E A “Utilization of cement treated recycled concrete aggregates as base or sub-base layer in Egypt ” 21 January 2013; accepted 14 February 2013 ,Available online 16 March 2013

• F A Sainz, A R Rodriguez “Real Application Of Cement Treated Mixed Recycled Aggregates On Road Bases In Malaga, Spain” Area of Construction Engineering – University of Cordoba.

• S Jayakody, C Gallage, A Kumar “Assessment of recycled concrete aggregates for road base and sub-base” Nov. 14-16, 2012, ISBN: 978-4-9905958-1-4 C3051.

• Satyanarayana V V, K L Chandra, T H Nandan, S V Gopala Raju “A study on the utilization of recycled aggregate and Crusher dust mixes as sub-base and base materials” ISSN 0976 – 6308 (Print) ISSN 0976 – 6316(Online) Volume 4, Issue 5, September – October, pp. 122-129.

• Robert M B, Mehmet C “Application of construction demolition waste for improving performance of subgrade and sub-base layers” PA 19122, USA IJRRAS 12 (3) ,September 2012.

• Chi S P “Feasible use of recycled concrete aggregates and crushed clay brick as unbound road sub-base” revised 9 December 2004; accepted 31 January 2005 Available online 23 March 2005.

60

Cont…• Dongxing X, Lambert J M H, Andre, A A Molenaar, Zhonghe S “Investigation of Combined

Effect of Mixture Variables on Mechanical Properties of Cement Treated Demolition Waste” Luoshi Road No. 122, 430070 Wuhan.

• Hasan T, Farhang F “Mechanical properties of cement stabilized mixtures of recycled asphalt And cement concrete for use in pavement” ISSN:2250-0138, Online 1(2) : 288-296, 2014 ISSN : 0976-2876.

• Parveen B, Dr Praveen, Dr R Goel, Department of Civil Engineering, NIT- Kurukshetra, “Use of Recycled Aggregates in Granular Sub Base”An ISO 3297: 2007.

• H Taherkhani “Evaluation of the Physical Properties of Unbound Base Layer Containing Recycled Aggregates” Vol. 6, No. 4, April 2015

• Parekh D N, Dr Modhera C D “Assessment of recycled aggregate concrete” ISSN 0976-7916.

• Sandeep Singh, Naresh Kumar “Specifications and recommendations for recycled materials used for various applications” ISSN: 2319-7463 Vol. 3 Issue 6, June-2014, pp: (86-90).

• Joralf A, Geir B “Evaluation of unbound crushed concrete as road building material – Mechanical properties v/s field performance” Gordana Petkovic Norwegian Public Roads Administration, Oslo, Norway.

• Rifat R, Salah T, Ali B, Hani B “Properties of recycled aggregate in concrete and road pavement applications” The Islamic University Journal (Series of Natural Studies and Engineering) Vol.15, No. 2, pp 247-264, 2007, ISSN 1726-6807.

61

Cont…• MoRT&H, Published by the Indian Roads Congress on behalf of the Govt of India, Ministry

of Road Transport and Highways, New Delhi.• Khanna.S.K, and Justo.C.E.G, "Highway material and pavement testing", Nemchand and

Brothers Publications, Roorkee 2009. Khanna.S.K, and Justo.C.E.G, "Highway material and pavement testing", Nemchand and Brothers Publications, Roorkee 2009.

• ASTM, American Society of the International Association for Testing and Materials.• AASHTO, American Association of State Highway and Transportation Officials.

62

THANK YOU