Compressive Strength of RHA Stabilised Earth Bricks Mixed ...

©Journal of Applied Sciences & Environmental Sustainability 3 (7): 132 - 145, 2017 e-ISSN 2360-8013

132 | P a g e

Research Article

Compressive Strength of RHA Stabilised Earth Bricks Mixed With Locust

Bean Pod Extract Umar Faruq Muhammad1, Habibu Tanimu2, Ahmad Hayaatuddeen2

1 Department of Architecture, Faculty of Built Environment, Universiti Teknologi Malaysia, 81310 Skudai, Johor

Bahru, Malaysia.

2 Department of Science Technology, Nasarawa State Polytechnic, Lafia, Nasarawa State, Nigeria.

Email: [email protected], +60133737200, +2348077441884

ARTICLE INFO

Article history

Received: 2/06/2017

Accepted: 04/07/2017

A b s t r a c t

Locust bean pod has been used for ages as traditional construction material for

water proofing of earth walls, floors and roofs. Modern researches have also

validated it usefulness as a binder for production of laterite bricks. The aim of

this study is to determine the compressive strength of Rice Husks Ash (RHA)

bricks treated with locust bean pod extract (LoPEx).Tests were carried out in

which different sample batches of RHA bricks, B1, B2 and B3, were molded.

The sample batches were differentiated by the quantity of LoPEx used in their

mixes, which are; 2, 4 and 8 head pans respectively. The compressive strength

of the samples were tested at 7, 14 and 28 days respectively. The results

showed that the extract can significantly increase the compressive strength of

RHA bricks. The strength also increased as the amount of extract was

increased. This is a confirmation of the high potentials of locust bean pod

extract being used as a binder in the production of RHA bricks. It is

recommended that a research be conducted on cement and RHA stabilized

earth bricks mixed with locust bean pod extract.

© Journal of Applied Sciences & Environmental Sustainability. All rights reserved.

RHA, LBP, LoPEx, Extract, Bricks, Traditional

1. Introduction

As a result of increased industrial and agricultural processes across the globe, there has been significant

increase in industrial and agricultural wastes which constitute environmental pollution. Much research

efforts in recent times are geared towards possible ways of recycling these wastes for re-use to keep the

environment clean, safe and sustainable. The construction industries have the greatest potentials for the

utilization of these wastes (Shafigh, Mahmud, Jumaat, & Zargar, 2014). The two main reason a lot of these

wastes are used or reused in construction is because, they can replace the expensive stone-based aggregates

in concrete mixes and can also replace the more expensive conventional (Vishwas & Gaikwad, 2013),


133 | P a g e

(Behera & Behera, 2013) and (Shaikh, Thorat, Unde, & Shirse, 2015) since they are pozzolanic in nature.

Continues experiments and researches have subjected earth material to various ‘wastes’ replacement; earth

has proven to be one of the, if not the, best natural building materials (Minke, 2006). In fact, where

Industrial Building Materials IBM) such as concrete and steel, have proven impossible to fulfill shelter

requirements, the vacuum is being replaced by ‘earth’ especially in the form of ‘stabilized ‘’soil blocks’’,

also known as stabilized Compressed Earth bricks (CEB). The stabilization here refers to agricultural waste

derived stabilizers such as rice husk ash (RHA) and locust bean pod extract (LoPex). Rice Husk Ash is one

excellent type of natural stabilizers that has seen extensive research and development; Khan et al., (2012)

proved that, 25% RHA as replacement of cement in concrete mix results in the same or better concrete than

conventional concrete mix. Locust Bean Pod Extract (LoPex) is another excellent additive which has been

proven by Aguwa & Okafor, (2012), to increase the compressive strength of laterite (soil) blocks

considerably. These researches have indeed validated the pozzolanic nature of these ‘wastes.’ The term,

‘pozzolan,’ is derived from the name ‘pozzuoli,’ a town situated near Mount Vesuvius. As an active

volcanic mountain, it occasionally produced ashes that were mined by the Romans years ago, and used in

the construction of their buildings as a binder in the same way cement is used today (Senapati, 2011).

Hence, other types of ashes like those of fuel, coal and rice husks, are categorized as pozzolans due to the

possession of binding enhancing properties. Pozzolans are either natural or artificial. Artificial ones are

those that occur due to man-made processes; for instance, fly ash which is one of the fine-particles residue

produced during coal combustion in a blast furnace (Pandian, 2013). There are also natural pozzolans such

as calcined clay, calcined shale and metakaolin. The pozzolanic properties of these and even other

substances are largely due to the silicates compounds found in them. They, by nature, usually react with soil

particles to form calcium silicate cement, in a reaction that is water insoluble. The binding or cementing

agents in the pozzolans are the same as those of the ordinary Portland cement. The difference is that, in

Portland cement, the calcium silicate gel is formed from the hydration of anhydrous calcium silicate,

whereas with pozzolans, the gel is formed by the removal of silica from the clay materials of the soil. When

this happens, the silicate gel proceeds immediately to coat and bind clay lumps in the soil together, and to

block off voids in the soil structure. In time, this gel gradually crystallizes into well-defined calcium silicate

hydrate, and the micro crystals also interlock. This reaction ceases on drying, as very dry soils will not react

with pozzolanic materials or cement (Argus and Gendut, 2002). For any ash or other substance to be a

pozzolan, it has to fulfill the requirements set out in Table 1 (Kaur, Farooq, & Singh, 2005).


134 | P a g e

Table 1: Requirements for fly ash and natural pozzolans for use as a mineral admixture in Portland cement concrete as per ASTM

C618-93.

1.1 Rice Husk Ash

About 120 million tons of rice husks are produced annually around the world as ‘agro-waste ’(Kumar,

Mohanta, Kumar, & Parkash, 2012). In Nigeria where about 3,000,000 tonnes of rice is produced annually,

the rice husk production is about 600,000 tonnes (Chukwudebelu, Igwe, & Madukasi, 2015). Rice husks are

basically composed of 80% organic volatile materials and 20% silica (James and SubbaRao, 1996) in

(Olawale & Oyawale, 2012) . Sabat & Nanda, (2011) however puts it at between 20% and 23% by weight

of the paddy. This varied composition of husks is due to geographical and climatic conditions, types of rice,

and the quantity of fertilizer used (Govindarao, 1980). Burning of rice husks produces rice husk ash (RHA)

Requirements Classification

N F C

Chemical Requirements

SiO2 + Al2O3 + Fe2O3, min % 70.0 70.0 50.0

SO3, max % 4.0 5.0 5.0

Moisture content, max % 3.0 3.0 3.0

Loss on ignition, max % 10.0 6.0 6.0

Physical Requirements

Amount retained when wet sieved on 45

Om. Sieve, max %

34 34 34

Pozzolanic activity index, with Portland

cement at 28 days, min % of control

75 75 75

Pozzolanic activity index, with lime, at 7

days, min (MPa)

5.5 5.5 -

Water requirement, max % of control 115 105 105

Autoclave expansion or contraction, max% 0.8 0.8 0.8

Specific gravity, max variation from

average.

5 5 5

% retained on 45 sieve, max Variation, and

% points from ave

5 5 5

NOTE *Class N: Raw or calcined natural pozzolan that comply with the application requirements for the class as given herein, such as some diatomaceous earths;

opaline cherts and shales; thufs and volcanic ashes or pumicites, calcined or uncalcined; and various materials requiring calcinations such as some clays and shales.

**Class F: Fly ash normally produced from burning bituminous coal that meets the applicable requirements for this class as given herein. This class of fly ash has

pozzolanic properties.

***Class C: Fly ash normally produced from lignite or sub bituminous coal that meets the applicable requirements for this class, as given herein. The class of fly ash, in

addition to having pozzolanic properties, also has some cementitious properties.


135 | P a g e

which is rich in silica, and can be an economically valuable raw material for the production of natural silica

(Kalapathy, Proctor, & Shultz, 2000). Despite the differences in compositions of different rice husks, some

form of proportional relationship can be discerned as depicted in Table 2.

Table 2: Typical chemical composition of rice husks

SiO2 91.75 88.32 89.08

Al2O3 2.07 0.46 1.75

Fe2O3 1.56 0.67 0.78

CaO 1.3 0.67 1.29

MgO 1 0.44 0.64

Na2O 0 - 0.85

K2O 2.32 2.91 1.38

LOI - 5.8 2.05

Source: (Pushpakumara & De Silva, 2012).

On the average, the highest chemical constituent is Silicon Dioxide (SiO2) while the lowest is Sodium

Oxide (Na2O). It is this high amount of SiO2 which is amorphous silica that results in the silica-rich residue

after the combustion process of the rice husks.

1.2 Locust Bean Pod

One important agricultural waste is the Locust Bean Pod obtained from the fruit of the African locust bean

tree, Parkia biglobosa. It is a perennial tree found in the savannah zone of West Africa, with multipurpose

use; as food, for soil fertility, as medicine, etc. The harvested fruits yield empty pods, which makes up

about 39% by weight of the fruit (Yisa & Jimoh, 2011). Use of locust bean pod extract has been a common

traditional practice in Northern Nigeria. The extract is mainly used as a bonding agent between traditionally

produced clay tiles and the soil beneath in the construction of durable floor finishes rooms. Some floors

constructed using this method have been in existence for the past fifty (50) years and above (Adama and

Jimoh, 2011). Locust bean pod, largely considered as waste agricultural biomass, has had extensive usage in

traditional buildings. The pods are soaked in water for at least, four days, and the extract used to mold mud

blocks for building purposes. Another way of using the pods is heaping them over mud block fences and as

soon as rain begins to fall on them, the leached solvent percolates down the wall to make it water resistant

after it dries up. In order to add to this body of knowledge, this study aims at establishing the compressive

strength of Rice Husk Ash-stabilized laterite bricks that are mixed with Locust bean Pod Extract (LoPEx).

The first objective is to produce rice husk ash using a very accessible method. The second objective is to

extract constituents from the locust bean pods. And the third objective is to establish effects of these

materials on compressive strength of earth bricks.


136 | P a g e

2. Materials and Methods

2.1 Leaching of the Locust Bean Pod

2.1.1 Collection of the LBP

The locust bean tree is abundant in the Northern Nigerian region generally and Nasarawa State particularly.

This research was conducted at the beginning of the locust bean harvest season that is the dry season which

is also hot season. All the pods used in this research were gotten from Keffi (villages of Taaka-laafiya,

Dorawa, Anguwan Gwandara, and ‘Yar-kadde) and Lafia (Agyaragu village); these two LGAs are in

Nasarawa State. Despite being the beginning of the harvest season, nonetheless, some factors affected the

supply of the pods. For instance, most of the producers in the villages have been used to pounding the

whole locust bean with a pestle and mortar, because they were primarily interested in the seed which they

use to produce a type of local food seasoning called ‘daddawa.’ Hence, our demand for only the pod meant

they had to manually peel the locust bean in order to preserve the pod as much as possible. That made the

gathering of the pods very time consuming and expensive.

2.1.2 Production of the Extract

The pods were bagged and transported to the outdoor Rice Milling neighbourhood in Lafia, Nasarawa State,

where they were boiled in large steel tanks for leaching. The entire pods, weighing 480kg, were put inside

3,600 litres of water. The mix was boiled for about 20min and left for 24 hrs to cool down. Boiling method

was used because solubility of the pods increased as the temperature of the water increased. Also, the

choice for water as the solvent was due to its very low viscosity, a property that allows it to circulate freely

than most solvents (Aguwa & Okafor, 2012). After that period, the residue pods were removed and

discarded. The liquid extract, which had a dark purple colour, was collected and used for the research

mixes.

2.1.3 Chemical Analysis of the Extract

The locust bean pod extract (LoPEx), was analyzed for its chemical constituents using the facilities of the

Federal University of Technology, Minna, Niger State’s Soil Science Laboratory. Atomic Absorption

Spectrophotometer (A.A.S.) was used for the analysis; this test is used to determine the metallic

constituents of silicate materials. The LoPEx, which is in solution form, is reduced to its elemental state and

vaporized. It is then drawn into a suitable flame which excites the outer most electrons to higher orbital.

After a short interval of time, the electrons return to ground state and a quantum of radiation is emitted.

Each constituent element is indicated by well-defined lines resulting from the emission (Muhammed, 1993)

in (Olawale& Oyawale, 2012). A result of this test is shown in Table 3.


137 | P a g e

2.2 Rice Husk Ash (RHA)

2.2.1 Collection of the Rice Husk

The husks were collected at Lafia, Nasarawa, where an active rice milling industry exists; shown in Figures

1a and 1b.

Figures 1a and 1b: Rice milling in Lafia

2.2.2 Production of the RHA

The researchers constructed a mass concrete slab in leased open field on which the sacks of rice husks were

emptied, as shown in Figure 2a. The heaps were large and their combustion was extremely slow, hence the

need to make them smaller; they were divided into heaps of about 1.2m in diameter and about 0.6m in

height. These heaps took up to 48hrs to burn down. The open air burning method was adopted, as shown in

Figure 2b, firstly because it provided a better pozzolanic property than controlled burning in a kiln or

furnace, since controlled method leaves residues of unburnt carbon in the ash (Akinyele, Salim, Oikelome,

& Olateju, 2015). Secondly, open method ensured that the burning temperature did not reach 7500 or above

which would have caused crystallization of the RHA, and consequently lead to excessive environmental

pollution (Krishnarao et al., 1992) in (Olawale & Oyawale, 2012). Thirdly, because it was a more accessible

method of burning to even low-income earners, which makes it sustainable. The husks at the core of the

heaps underwent more complete combustion due to less oxygen. The resulting RHA was carefully skimmed

at intervals and the remaining unburnt husks are rekindled; shown in Figure 2c and 2d. At the end, the ash

was collected, and bagged for transportation to the research station, situated at the Nasarawa State

Polytechnic, Lafia.


138 | P a g e

Figures 2a, b, c and d: Production of rice husks ash by the researchers.

2.2.3 Chemical Analysis of the RHA

The RHA was also analysed for its chemical constituents at the same laboratory in Minna, Niger State, and

the results are shown in Table 3.

Table 3: Chemical composition of the RHA and LoPEx

Parameters RHA (%) LoPEx (%)

SiO2 55.09 42.67

Al2O3 8.25 9.92

Fe2O3 6.22 5.89

P2O5 0.04 2.02

CaO 10.59 9.78

MgO 1.02 1.00

Na2O 1.89 0.86

LOI 13.02 11.99

2.3 Laterite Soil

The soil used in the research was sourced from Gandu area of Lafia L.G.A. Laterite was used because it is a

generally iron rich soil with a hard ferruginous surface expression and some degree of chemical and

mineralogical differentiation below (Eggleton 2001) in (Saynor& Harford, 2010).

2.4 Production of the Bricks

The test-bricks used were produced in batches; 1, 2, 3, based on the different quantities of their mix

materials namely, laterite soil, RHA, and LoPEx. A batch 4 was produced as the Control Group (CG), with

its materials being laterite soil, rice husk ash, and little water.


139 | P a g e

In all the three test batches, quantities of the laterite soil and the rice husk ash remained constant while the

amount of LoPEx was varied; as shown in Table 4.

Table 4: Quantities of materials for bricks production

Laterite RHA LoPEx Qty in ‘head

pans’ Qty head pans % of Mix Qty head pans % of Mix

Batch (CG) 11 73 4 27 Enough water

Batch 1 11 73 4 27 2

Batch 2 11 73 4 27 4

Batch 3 11 73 4 27 8

In the entire measurement of the materials, head pan was used, and the materials were measured level with

the rim of the head pan. The head pan was adopted because limited intelligence was required before using

it, and it is a basic tool in construction. It was also used because of easy accessibility and convenience to the

common man. The 27% amount of RHA replacement level was used in the mix, in line with Dakroury et al.

(2008) and (Givi, Rashid, Aziz, & Salleh, 2010) in (Torkaman, Ashori, & Sadr Momtazi, 2014).

2.4.1 Preparation of the Batches’ Mixes

For all the batches, the laterite soil was first sieved using measured unto a clean concrete slab casted for that

purpose. Shovels were used to spread the soil thin and then the RHA was also spread over it. The two were

dry-mixed over and over using the shovels, until an even mix was achieved. After that, the mix was again

spread thin but with ridges and valleys round, and then the required amount of LoPEx was slowly poured

into the valleys. For the fact that the laterite soil was a little bit damp, it became necessary to allow the

Batches to soak the extract for some time; Batch 1 for 1 day, Batch 2 for 3 days, and Batch 3 for 8 days, in

order to get them dry enough to be moldable. The increasing number of waiting days was due to the

respective increasing amount of the LoPEx. At the end of the periods of days the mixes formed into lumps

which had to be broken down by use of shovels again.

2.4.2 Molding of the Bricks

Molding was carried out by the use of a locally fabricated, manually operated machine press, which was

fabricated by SOLBATEC in Nigeria; Figure 3. The sizes of the molded bricks, refered to as, Rice-Husk-

Ash-Locust-Extract, RHALex for short, are shown in Table 5. A total of 12 bricks were molded; 3 bricks

for every Batch.


140 | P a g e

Figure 3: The manually operated brick molding machine.

Table 5: Size of the brick samples molded

Length (mm) Width (mm) Height (mm)

210 100 100

3. Results and Discussion

3.1 Chemical Analysis of the RHA and LoPEx

The analysis results, showing quantities of the respective chemical constituents of both the RHA and LoPEx

are presented in Table 4. From the results, sum of the percentages of the chemical compounds in the RHA,

SiO2 + Al2O3 + Fe2O3, is 69.56%. This is approximately 70% which satisfies the minimum ASTM C618-

93 standards for class “F” pozzolana, in Table 1. Loss on Ignition of the RHA is 13.02%, which is higher

than Table 1. This is not a problem (Oda, 2003) and can be accepted (Awal & Shehu, 2013) because it only

shows that the time was not enough for total removal of carbon from the RHA. For the LoPEx, the sum of

these compounds is 58.48% which also satisfies the standard of 50% minimum for class “C” natural

pozzolana. Its Loss on Ignition is 11.99% which is similarly higher than the standard, and also acceptable as

the RHA. Most important though, is the fact that both materials are proven to be pozzolana based on ASTM

C618.

3.2 Compressive Strength Test of the Bricks

Compressive strength test was carried out on all the brick samples – Control Group (CG), Batch 1, Batch 2,

and Batch 3. The results are in Tables 6, 7, 8 and 9.


141 | P a g e

Table 6: Compressive Strength test of RHALex Batch 4: The Control Group bricks

Brick

no

Date cast Date

tested

Age

for

testing

(days)

Structure Wt.

of

bricks

(g)

Density

of

bricks

(kg/m3)

Crushing

load

(KN)

Area

(mm2)

Crushing

strength

(N/mm2)

Ave

strength

(N/mm2)

RHAL 30/06/’13 28/07/’13 28 BRICKS 8035 1287 60 48000 1.3 1.1

‘’ ‘’ 8134 1303 48 ‘’ 1.0

‘’ ‘’ 7704 1234 48 ‘’ 1.0

Table 7: Compressive Strength test of Batch 1, 2 and 3 at 7 days

Bric

k no

Date cast Date tested Age

for

testin

g

(days)

Structur

e

Wt.

of

brick

s (g)

Density

of

bricks

(kg/m3

)

Crushin

g load

(KN)

Area

(mm2

)

Crushing

strength

(N/mm2

)

Ave

strength

(N/mm2

)

B1

10/06/201

3

17/06/201

3

7 BRICKS 7996 1281 40 48000 0.83

0.86 ‘’ ‘’ 8137 1304 48 ‘’ 1.00

‘’ ‘’ 7888 1264 36 ‘’ 0.75

B2

10/06/201

3

17/06/201

3

‘’ BRICKS 7666 1229 40 ‘’ 0.83

0.75 ‘’ ‘’ 7382 1183 40 ‘’ 0.83

‘’ ‘’ 7467 1197 28 ‘’ 0.58

B3

10/06/201

3

17/06/201

3

‘’ BRICKS 8414 1348 80 ‘’ 1,67

1.56 ‘’ ‘’ 8328 1335 64 ‘’ 1.33

‘’ ‘’ 8356 1339 80 ‘’ 1.67


142 | P a g e


Brick

no

Date cast Date tested Age

for

testin

g

(days)

Structur

e

Wt.

of

brick

s (g)

Density

of

bricks

(kg/m3

)

Crushin

g load

(KN)

Area

(mm2

)

Crushing

strength

(N/mm2

)

Ave

strength

(N/mm2

)

B1

10/06/20

13

24/06/201

3

14 BRICKS 7781 1247 40 48000 0.83

0.89 ‘’ ‘’ 7792 1249 40 ‘’ 0.83

‘’ ‘’ 7702 1234 48 ‘’ 1.00

B2

10/06/20

13

24/06/201

3

‘’ BRICKS 8057 1291 52 ‘’ 1.08

1.03 ‘’ ‘’ 7584 1215 56 ‘’ 1.17

‘’ ‘’ 7494 1201 40 ‘’ 0.83

B3

10/06/20

13

24/06/201

3

‘’ BRICKS 8410 1348 56 ‘’ 1.17

1.20 ‘’ ‘’ 8180 1311 56 ‘’ 1.17

‘’ ‘’ 8079 1295 60 ‘’ 1.25


Brick

no

Date cast Date

tested

Age

for

testing

(days)

Structure Wt.

of

bricks

(g)

Density

of

bricks

(kg/m3)

Crushing

load

(KN)

Area

(mm2)

Crushing

strength

(N/mm2)

Ave

strength

(N/mm2)

B1

10/06/2013 08/07/13 28 BRICKS 7648 1226 40 48000 0.83

0.76 ‘’ ‘’ 7745 1241 32 ‘’ 0.67

‘’ ‘’ 7862 1260 38 ‘’ 0.79

B2

10/06/2013 08/07/13 ‘’ BRICKS 7421 1189 36 ‘’ 0.75

0.67 ‘’ ‘’ 7554 1211 28 ‘’ 0.58

‘’ ‘’ 7522 1205 32 ‘’ 0.67

B3

10/06/2013 08/07/13 ‘’ BRICKS 8288 1328 32 ‘’ 0.67

0.89 ‘’ ‘’ 8184 1312 60 ‘’ 1.25

‘’ ‘’ 8192 1313 36 ‘’ 0.75


143 | P a g e

4. Discussion

The compressive strength of the RHALex bricks is measured against the postulation that both materials are

pozzolanas. Looking at Tables 6, 7 and 8, for all the samples B1, B2 and B3, their average strengths

increase with the age of the bricks from 7days. Table 6 shows that at 7days, B3 with 1.56N/mm2 is stronger

than B1 of 0.86N/mm2 and B2 of 0.75N/mm2. Similarly, Table 7 shows that at 14days, B3 with 1.20N/mm2

is stronger than B1 with 0.89N/mm2 and B2 with 1.03N/mm2. At 28days; Table 8, the results are also

similar. This can be more clearly seen in Table 10, at least for B1 and B2. Quantities of the LoPEx,

increased from B1 to B3, resulted in increased average compressive strength. This increase supports the

assertion on the pozzolanic nature of LoPEx, even though a lot of individual brick samples possess lower

average strengths than the CG at Hence, even at 7days, a RHALex brick attains its optimum compressive

strength for use in construction. This could be attributable to continues evaporation of the LoPEx from the

samples during curing. However, these increases and decreases are not significant with the increase in age

of curing. Furthermore, the higher the quantity of LoPEx in the mixes, the higher the average strength of the

samples;

Table 10: Average compressive strengths of sample batches related to age.

At 7 days

B1

Ave strength

(N/mm2)

B2

Ave strength

(N/mm2)

B3

Ave strength

(N/mm2)

Control Group Ave

strength

(N/mm2)

5. Conclusions

Locust bean pod, considered as waste in modern times but traditionally used in building construction ages

ago, has been processed and tested in this research. Its extract, LoPEx, was used to mold bricks that have

been stabilized with rice husk ash, RHA. The bricks were tested afterwards to determine their compressive

strengths. The results showed that the LoPEx increases the compressive strength of RHA stabilized earth

bricks. The strength can also be increased by increasing the quantity of the LoPEx in the earth mix. The

research results have therefore shown that RHALex bricks have the potentials to be used as construction

materials, which would ensure the utilization of LBP and rice husks. This would consequently lead to

environmental sustainability.


144 | P a g e

References

Aguwa, J. I., & Okafor, J. O. (2012). Preliminary Investigation in the Use of Locust Bean Pod Extract as

Binder for Production of Laterite Blocks for Buildings. International Journal of Environmental

Science, Management and Engineering Research, 1(2), 57–67.

Akinyele, J. O., Salim, R. W., Oikelome, K. O., & Olateju, O. T. (2015). The Use of Rice Husk Ash as a

Stabilizing Agent in Lateritic Clay Soil. World Academy of Science, Engineering and Technology,

International Journal of Civil, Environmental, Structural, Construction and Architectural

Engineering, 9(11), 1392–1396.

Awal, A. S. M. A., & Shehu, I. A. (2013). Evaluation of heat of hydration of concrete containing high

volume palm oil fuel ash. Fuel, 105, 728–731. https://doi.org/10.1016/j.fuel.2012.10.020

Behera, G. C., & Behera, R. K. (2013). Effect Of Coconut Shell Aggregate On Normal Strength Concrete

Running Title: Coconut Shell As Coarse Aggregate. International Journal of Engineering Research

& Technology, 2(6), 2405–2415.

Chukwudebelu, J. A., Igwe, C. C., & Madukasi, E. I. (2015). Prospect of using whole rice husk for the

production of dense and hollow bricks. African Journal of Environmental Science and Technology,

9(5), 493–501. https://doi.org/10.5897/AJEST2013.1631

Givi, A. N., Rashid, S. A., Aziz, F. N. A., & Salleh, M. A. M. (2010). Contribution of rice husk ash to the

properties of mortar and concrete: a review. Journal of American Science, 6(3), 157–165.

Govindarao, V. M. H. (1980). Utilization of rice husk-a preliminary-analysis. Journal of Scientific &

Industrial Research (JSIR), 39(9), 495–515.

Kalapathy, U., Proctor, A., & Shultz, J. (2000). A simple method for production of pure silica from rice hull

ash. Bioresource Technology, 73(3), 257–262. https://doi.org/10.1016/S0960-8524(99)00127-3

Kaur, I., Farooq, U., & Singh, H. (2005). MECHANICAL PROPERTIES OF HIGH VOLUME FLY ASH

(HVFA) CONCRETE SUBJECTED TO ELEVATED TEMPERATURES UP TO 120 C. Retrieved

from: http://bit.ly/2v4vzjq

Khan, R., Jabbar, A., Ahmad, I., Khan, W., Khan, A. N., & Mirza, J. (2012). Reduction in environmental

problems using rice-husk ash in concrete. Construction and Building Materials, 30, 360–365.

https://doi.org/10.1016/j.conbuildmat.2011.11.028

Kumar, A., Mohanta, K., Kumar, D., & Parkash, O. (2012). Properties and Industrial Applications of Rice

husk: A review. International Journal of Emerging Technology and Advanced Engineering, 2(10),

86–90.

Minke, G. (2006). Building with Earth: Design and Technology of a Sustainable Architecture. Birkhauser.

http://bit.ly/2v4vzjq


145 | P a g e

Olawale, O., & Oyawale, F. A. (2012). Characterization of rice husk via atomic absorption

spectrophotometer for optimal silica production. International Journal of Science and Technology,

2(4), 210–213.

Pandian, N. S. (2013). Fly ash characterization with reference to geotechnical applications | Pandian |

Journal of the Indian Institute of Science. Journal of the Indian Institute of Science, 84(6), 189.

Pushpakumara, B. H. J., & De Silva, G. S. (2012). Characteristics of Masonry Blocks Manufactured with

Rice Husk Ash (RHA) and Lime. Engineer, 45(03), 1–10.

Sabat, A. K., & Nanda, R. P. (2011). Effect of marble dust on strength and durability of rice husk ash

stabilized expansive soil. International Journal of Civil and Structural Engineering, 1(4), 939–948.

Saynor, M. J., & Harford, A. (2010). Pilot study on the separation and physical characterisation of lateritic

material (Internal Report No. Internal Report 579) (p. 24). Darwin: Department of Sustainability,

Environment, Water, Population and Communities.

Senapati, M. R. (2011). Fly ash from thermal power plants – waste management and overview. Current

Science, 100(12), 1791–1794.

Shafigh, P., Mahmud, H. B., Jumaat, M. Z., & Zargar, M. (2014). Agricultural wastes as aggregate in

concrete mixtures – A review. Construction and Building Materials, 53, 110–117.

Shaikh, A. S., Thorat, S. B., Unde, R. V., & Shirse, P. S. (2015). Advance Concrete-Aggregate replaced by

Coconut Shell. International Research Journal of Engineering and Technology, 02(05), 698–702.

Torkaman, J., Ashori, A., & Sadr Momtazi, A. (2014). Using wood fiber waste, rice husk ash, and

limestone powder waste as cement replacement materials for lightweight concrete blocks.

Construction and Building Materials, 50, 432–436.

https://doi.org/10.1016/j.conbuildmat.2013.09.044

Vishwas, P. K., & Gaikwad, S. K. B. (2013). Comparative Study on Coconut Shell Aggregate with

Conventional Concrete. International Journal of Engineering and Innovative Technology, 2(12),

67–70.

Yisa, A. A., & Jimoh, Y. A. (2011). Production And Classification Of Locust Bean Pod Ash (LBPA) As A

Pozzolan. Ministry of Works and Infrastructural Development, Minna, Nigeria and Department of

Civil Engineering: University of Ilorin, Nigeria. Retrieved from: http://bit.ly/2w5BcLE

http://bit.ly/2w5BcLE

Compressive Strength of RHA Stabilised Earth Bricks Mixed ...

Documents

Transcript of Compressive Strength of RHA Stabilised Earth Bricks Mixed ...