The document summarizes a study on volcanic soil materials and their stability in road construction. Laboratory tests were conducted on samples collected from the Ruvunda Quarry in Musanze District, including sieve analysis, Atterberg limits, proctor tests, CBR tests, and compressive strength tests of sized stones and concrete made with volcanic aggregates. The results showed that the volcanic materials were predominantly non-plastic gravel and sand that could be suitable for road base or subbase layers. Stabilizing one sample with cement increased its strength and density. The study concluded that volcanic soils can serve as local materials for road construction in Rwanda when properly classified and tested.

1. Done by: Eng. Patrick nteziryayo
A STUDY ON VOLCANIC SOIL MATERIALS
AND ITS STABILITY IN ROAD
CONSTRUCTION.
Supervisor: Dr.Eng. Jean de Dieu NZABONIMPA
CIVIL ENGINEERING DEPARTMENT
patrickstrongvoice@gmail.com
patrickstrongvoice
+250783682225
Contact information
Case study:Musanze District-Ruvunda Quarry

2. A.
• General introduction.
B.
• Problem statement and Research Questions
• The general objective and the specific objective
• Limitation of the research
• Methodology
• Lab Works(Sample Preparation, Testing , test results and
interpretations )
C. • Conclusion
• Recommendations

3. Volcanic soils
cover 1 % of
the earth’s
surface.
Volcanic soils cover
1% of the Earth’s
surface yet support
10% of the world’s
population, including
some of the highest
human population
densities.

4.  In the construction industry, volcanic materials can be used in Road
construction in some road layers such as Subgrade, subbase and Base
course, they also used as paved stones in parking areas and in construction
of retaining walls or water channels etc.…The construction materials to be
used are always provided before the construction activities.
As it is well known, Musanze and Rubavu district
located in a volcanic region and the most soil material
which is commonly founded in this region is volcanic
soil material, this project of technical study on volcanic
soil material helped to understand and to identify the
quality of the volcanic soil material and to be sure with
where it can be used in road construction for some
road layers , parking areas and paved road with sized
volcanic stone.

5.  One of the major causes of roads failure constructed by using
volcanic soil material is the less skills of knowing how and where this
volcanic soil material can be used in some road layers. Some people
haul the construction materials such as sand and gravel far from site
areas which is even very expensive while they could be using volcanic
sand & gravel materials. Figure illustrates some failed area due to
poor drainage system and less skills of knowing where volcanic
material can be used in some road layers.
 The mechanical properties of the volcanic soils found in
Rwanda were overlooked.
Failed Road in Musanze District: Source the New times published: May 06, 2013, Peterson
tumwebaze
Failure of the road due to
improper compaction

6. The aims of this research was to find solutions to the questions below:
*What is the soil classification of volcanic soil material based on soil
full identification?
* Can volcanic material be stabilized with cement for densification?
* What is the compressive strength of sized stone of volcanic material?
* What is the concrete compressive strength made up with volcanic
gravel and sand mixed with cement?

7. In order to achieve specific objectives, some research questions were stated above. The
research questions were tabled together with their corresponding specific objectives.
• Volcanic Soil material
-To conduct full identification of soil (Sieve analysis, atterberg limit, proctor test, CBR
(California Bearing Ratio) Test and 1% of cement were used in volcanic soil
stabilization(densification).
-To determine the compressive strength of sized volcanic material,
-To determine the resistance due to fragmentation of the crushed stone volcanic
material by performing Los Angeles test.
-Concrete mix design was done for volcanic material(sand and gravel) to achieve C25.

8.  This study focused on Technical study on volcanic soil
material and its stability where it is needed. This study
was conducted on the Quarry that is located in
MUSANZE District, KIMONYI Sector, RUVUNDA
cell. It is based on most useful volcanic soil quarry
known as RUVUNDA Quarry.
S2
S3
S1

9. Concept framework

10. Sample I Collected from
Ruvunda Quarry
Sampling date: 11-May-2018
Sample II Collected from
Ruvunda Quarry
Sampling date: 11-May-2018
Sample III Collected from
Ruvunda Quarry
Sampling date: 11-May-2018
Sized Volcanic stone
Ruvunda Quarry
During the technical study of this research on volcanic soil materials in the civil engineering laboratory
test method, sample preparation, test procedures and reporting were referred to the laboratory soil testing
books (TMH1 Technical Methods for Highways with Standard methods of testing road construction
material Edition 2.1986., Tanzania laboratory testing material and BS 1377 part 2, 1990) and Rwanda
standard.
Laboratory work(Sample preparation & Testing)

11. SAMPLEDESCR. RUVUNDA QUARRY REF
Sample N°1 Sample N°2 Sample N°3
Wt of wet soil + container
Wt of dry soil + container
LL: PL: P.I:
Wt of container
Wt of moisture
Wt of dry soil
Moisture content Ψ %
Average %
LIQUID LIMIT TEST PLASTIC LIMIT TEST
Number of blows
N° of container
SAMPLEI
ATTERBERGLIMITS
10 15 20 25 30 35 40 45 50
Moisturecontent%
Number of blows
NO MESURABLE
5(mm)%
RETAINED
2(mm)%
RETAINED
0.075(mm)%
PASSING
GRAVEL
%
SAND
%
FINE
%
Sample I 28.30 39.73 3.59 39.73 56.68 3.59 Sandy Material
Sample II 63.57 85.86 3.17 85.86 10.97 3.17 Gravely Material
Sample III 43.17 43.17 8.14 43.17 48.70 8.14 Sandy Material
Stabilized 27.25 27.25 7.17 27.25 65.58 7.17 Sandy Material
Sieve analysis
ClassificationITEMS
NO MEASURABLE
Used sieves for sieve analysis test
Used casagrande device for atterberg limit

12. SAMPLE I Classification
MC % 8.92 10.50 12.30 14.45 OMC 12.30
DD 1.50 1.64 1.76 1.60 MDD 1.76 Quite good
SAMPLE II
MC % 7.14 9.49 11.21 13.26 OMC 11.21
DD 1.55 1.71 1.78 1.69 MDD 1.78 Quite good
SAMPLE III
MC % 10.76 12.59 14.25 16.13 OMC 14.25
DD 1.55 1.66 1.74 1.67 MDD 1.74 Poor
STABILIZED
MC % 2.46 4.32 6.44 8.43 OMC 6.44
DD 1.53 1.73 1.88 1.70 MDD 1.88 Quite good
PROCTOR OR COMPACTION TEST
1.50
1.64
1.76
1.60
1.55
1.71
1.78
1.69
1.55
1.66
1.74
1.67
1.53
1.73
1.88
1.70
1.45
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00
MDD
OMC
Combination of Proctor Test
SAMPLE 1 SAMPLE II SAMPLE III STABILIZED
Proctor Test
Proctor test equipment
Compacting volcanic soil samples
Weighting compacted samples

13. SAMPLE I Unstabilized
CBR@ 100% 98.00% 95%
Dry Density 1.76 1.73 1.67
CBR Value(%) 60.20 54.00 41.00
SAMPLE II Unstabilized
Dry Density 1.78 1.75 1.69
CBR Value(%) 62.33 50.00 40.00
SAMPLE III Unstabilized
Dry Density 1.74 1.70 1.65
CBR Value(%) 51.94 41.00 31.00
STABILIZED with cement 1%
Dry Density 1.88 1.84 1.78
CBR Value(%) 106.41 96.00 80.00
CBR TEST COMPARISONS
1.60
1.65
1.70
1.75
1.80
1.85
1.90
0.00 20.00 40.00 60.00 80.00 100.00 120.00
DryDensity
CBR Value(%)
COMBINATIONOFMDD VsCBR
SAMPLE I SAMPLE II SAMPLE III STABILIZED
CBR TEST RESULTS

14. RUVUNDA QUARRY SAMPLEI
N°
Sample
identification
Sample
Product
Date.
Testing
Date
Sample
Age(Days)
Surface
( Cm2
)
Volume
(Cm3
)
compressive
strength
(Mpa)
Average
Compressive
strength (Mpa)
Load
(KN)
Weight
( g).
Density
(g/Cm3
)
Average
Density
(g/cm3
)
1 53.05 1500 2345 2.76
2 47.75 1350 2391 2.82
3 48.45 1370 2357 2.78
Sized Stone
Pavers
11-May-18 19-Jul-18 69 282.75 848.25 49.75 2.79
SAMPLEDESCR.
SIZED STONECOMPRESSIVESTRENGTH.
2.70
2.80
2.90
2.76
2.82
2.78
COMPRESSIVE
STRENGTH(MPa)
Density (g/cm3)
RUVUNDA QUARRY SAMPLEI
Trial I II
Average value %
REF
Weight of saturated
surface-dry sample(g)
2379.5 2500.5
Weight of oven dried
sample(g)
2330 2435
Water absorption% 2.124 2.690
2.407
WATERABSORPTIONTEST
Unsized stone Sized stone

15. SAMPLEDESCR. RUVUNDA QUARRY SAMPLEI
9.5/12.5 12.5/19 10/14 16/25 20/25 25/31.5
Weight of specimens g 5000
Number of balls - 12
Weight of specimens >
1.7mm
g 3538
Weight of specimens<
1.7mm
g 1462
L.A coefficient. % 29.2
Remark :The resistance to the fragmatation has the value of the coefficient about 29.2%
Grading classes U 2.36/4.75 6.3/9.5
10/19 10/25 10/31.5
REF
LOS-ANGELESTEST
SAMPLE DESCR. QUARRY RUVUNDA
12 12 12.5
9.3 9.5 9.9
77.5 79.2 79.2
Height of the floculat H1 (cm)
Height of the sediment H2 (cm)
Equivalent of sand 100*(h2/h1) cm
Average of 3 measures (%) 78.6
SAND
SAND EQUIVALENT
Used machine for losangeles test
Performing sand equivalent test

16. N°
Sample
identification
Sample
Product
Date.
Testing
Date
Sample
Age( Days)
Surface
( Cm2
)
Volume
(Cm3
)
compressive
strength
(Mpa)
Average
Compressive
strength(Mpa)
Load
(KN)
Weight
( g).
Density
(g/Cm3
)
Average
Density
(g/cm3
)
1 26.67 600 7895 2.34
2 26.44 595 7855 2.33
3 27.11 610 7848 2.33
2.33
VARIATION CHART FOR COMPRESSIVE STRENGTH
Concrete
Cube
24-Jul-18 21-Aug-18 28 225 3375 26.74
SAMPLE DESCRIPTION LAB TRIAL MIX ON VOLCANIC MATERIAL USED CEMENT:CIMERWA 42.5 PPC
CONCRETECOMPRESSIVESTRENGTH.
26.00
27.00
28.00
2.34
2.33
2.33
26.67
26.44
27.11
COMPRESSIVESTRENGTH
(MPa)
Density (g/cm3)
Fresh concrete workability of concrete
Concrete cube before testing
Concrete cube in compression machine
Concrete cube after crushing

17. 5(mm)%
RETAINED
2(mm)%
RETAINED
0.075(mm)%
PASSING
GRAVEL
%
SAND
%
FINE
%
LL (%) PL (%) IP(%) ɣs(kg/cm
3
) w (%)
Yd OPM at
95%
ID EASTING(X) NORTHING(Y) ELEVATION(Z) Sample I 28.30 39.73 3.59 39.73 56.68 3.59 Sandy Material 1.76 12.30 Quite Good 1.67
S1 454713 4832918 1864 Sample II 63.57 85.86 3.17 85.86 10.97 3.17 Gravely Material 1.78 11.21 Quite Good 1.69
S2 454843 4833076 1872 Sample III 43.17 43.17 8.14 43.17 48.70 8.14 Sandy Material 1.74 14.25 Poor 1.65
S3 454580 4833000 1868 Stabilized 27.25 27.25 7.17 27.25 65.58 7.17 Sandy Material 1.88 6.44 Quite Good 1.78
29.2
Density
(g/cm3)
2.407
2.53
2.69
78.60
+
18.74 Average Compressive Strength 26.74
Used Softwares
Microsoft Office
ArchMap
Zotero 5.1
Google Earth
AutoCad
0.569W/C Mixed Quantities for six cubes
C25-Concrete Compressive Strength
after 7 Days Soaked In Water after 28 Days Soaked In Water
7.938
15.942
25.426
4.103
CEMENT
SAND
GRAVEL
WATER
49.75 2.79
Sand Specific Gravity
Gravel Specific Gravity
Sand Equivalent (%)
Average Compressive Strength
Average
Compressive
Strength(Mpa)
SUMMARY SHEET OF TECHNICAL STUDY ON VOLCANIC SOIL MATERIAL
Losangeles Test (%)
Water Absorption(%)
Aggregates
Proctor
C25-MIXING RATIO(Kg/m3)
LAB TRIAL MIX QUANTITIES IN
KG
Ruvunda Quarry and Sample Locations Sieve analysis
Classification
Sample Preparation for sized stones Compressive strength of sized stone
Atterberg Limite
Data CollectionData Collection ITEMS Classification USCS
350
702.935
GP
(Poorly Graded )
1121.08
No Cohesive
Material
199.39
NO-MEASURABLE
CBR Test
CBR at 95%
41.00
40.00
31.00
80.00
Classification
S2
S3
S1
17.5
18
18.5
19
19.5
2.334814815
2.325925926
2.339259259
18.88888889
18.22222222
19.11111111
COMPRESSIVESTRENGTH(MPa)
Density (g/cm3)
26
26.5
27
27.5
2.339259259
2.327407407
2.325333333
26.66666667
26.44444444
27.11111111
COMPRESSIVESTRENGTH(MPa)
Density (g/cm3)
44.00
46.00
48.00
50.00
52.00
54.00
2.76
2.82
2.78
53.05
47.75
48.45
COMPRESSIVESTRENGTH(MPa)
Density (g/cm3)

18.  General conclusion
“Technical study on volcanic soil material and its stability in road
construction.”
Volcanic soil material were classified as cohesionless material and mainly
material obtained from Ruvunda volcanic quarry are stones, gravels and
sand. These findings demonstrated that volcanic soils with category quartzite
can be good materials to serve as local materials for the implementation of
road construction in Rwanda.
Recommendation
To the further researchers to work on how the volcanic soil material can be
mixed with cohesive material in order to get the medium plastic index so, it
can be classified as well graded material and to check the concrete
permeability made up with cement and volcanic sand and gravel.

19. patrickstrongvoice@gmail.com
patrickstrongvoice
+250783682225
+250788330550
Contact information