Dissertation aparna 19.10.15.docx

7/21/2019 Dissertation aparna 19.10.15.docx

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Critical appraisal of compressed stabilized earthblocks and straw bale as sustainable buildingmaterialsAparna Thampi

Anooja Jayalakshmi

Abstract:

Global warming and climate change are hotly debated issues in the current world scenario. The world has already begun to succumb to injuries infictedby climate change. So worldwide eorts are on to tackle this menace under the aegis o several organiations. !very s"here o human activity cancontribute towards this aim. #t is here that as architects o the uture worldour contributions matter. $wing to the "henomenal growth in the buildingindustry worldwide% there has been an un"aralleled level o e&"loitation o natural resources in an un"lanned and unchecked way. 'ence% in today(sworld% )going green* has become a to" "riority in our society. #ntegratinggreen materials into building "rojects can hel" reduce the environmentalim"acts associated with the e&traction% trans"ort% "rocessing% abrication%installation% dis"osal o these materials etc.The aim o the dissertation is to conduct an analysis on two sustainablebuilding materials namely% +om"ressed Stabilied !arth ,locks -+S!, andstraw bale% to identiy their eectiveness as sustainable building materials.The materials are studied in detail% its merits and demerits are analyed andre/uired data are collected through literature studies and case studies. +S!,is a building material that is gaining wide acce"tance as sustainable materialtoday. #t is a s"ecial technology in which blocks are made by com"ressing acombination o earthen material and added stabiliers. #ts local availability and ease o "rocessing makes it the most energy e0cient building material.Straw is one o the 1nest renewable materials available. #n a country like#ndia% where agriculture is widely "racticed% using the abundantly availablestraw as a building material can be advantageous. 2hen bundled together into a bale% it becomes a solid block that is highly resistant to decom"osition.These materials "rovide better% e0cient% durable and cost eectiveconstruction to ensure least "ossible degradation o environment.

3eywords: sustainable materials% +S!,% straw bale% merits% demerits

1. Introduction

+ollege o Architecture Trivandrum 1



A “Green building is a structure that uses processes that are resourcee!cient throughout buildings life cycle" from citing to design# construction#operation# maintenance# reno$ation and demolition% There is a need to studyabout green technology as green buildings aim at reducing o$erall impact of

built en$ironment on human health and natural en$ironment by" e!cientlyusing energy# water and other resources& protecting occupant health andimpro$ing employee producti$ity& reducing waste# pollution and en$ironmentdegradation% 'tudying it thereby helps to produce sustainable designsensuring a safe future for the coming generations%Compressed 'tabilized (arth )locks is a special technology in which blocksare made by compressing a combination of earthen material and with addedstabilizers% *ts local a$ailability and ease of processing makes it the mostenergy e!cient building material% 'traw is one of the +nest renewablematerials a$ailable and is found around the world in abundance% *ts chemicalcomposition is primarily cellulose% 'traw bale construction is a techni,ue

which is slowly gaining acceptance these days% This method pro$es to besuccessful in locations where moisture in air is less as there might be pestand termite attacks otherwise% )esides being eco-friendly# the otherad$antages of using these materials for construction are& )etter functionale!ciency& Cost e.ecti$eness& )etter durability& (ase of construction& )etter+nish& /inimum waste& less maintenance cost

2. Aim

To conduct a critical performance appraisal of two building materialsnamely Compressed 'tabilized (arth )locks and 'traw )ale assustainable building materials%

3. Need for the study

*n the modern times $ariety of materials are used for construction% These include natural as well as arti+cial materials# which are ha$ingits own merits and demerits% /aterials are selected for a constructionbased on the characteristics re,uired for the building# a$ailability#durability# workability and cost etc% The current trend is to selectnatural materials which are en$ironmental friendly# a$ailableabundantly and cheaper% C'() and straw bale are few naturalmaterials which are gaining acceptance as sustainable buildingmaterials

4. Objective

• To study the importance of sustainable building materials

• To study the e!ciency of two sustainable building materials in terms of its eco-friendliness# life cycle performance# other ,ualities and analyzetheir merits and demerits

5. Methodology



.1 !om"ressed #t$bili%ed &$rth 'loc(s

C'() has now become an earth technology that is being used worldwide

because it attempts to re$i$e traditional skills and to link ancestral and$ernacular traditions of raw earth constructions with the modern technologyof stabilized earth% The main research and de$elopment is focused onminimizing the use of cement# steel# and reinforced cement concrete 0CC2%Compressed earth block is a building material that is made primarily fromdamp soil compressed at high pressure to form blocks% *f the blocks arestabilized with a chemical binder# they are called compressed stabilizedearth blocks% 'tabilization is the process of adding certain compounds to theearth so as to impro$e their properties% Two types of stabilizers used in C'()manufacturing are& cement or lime% The input of soil stabilization allowedpeople to build higher with thinner walls# which ha$e a much better

compressi$e strength and water resistance% 3ith cement stabilization# theblocks must be cured for four weeks after manufacturing% After this# they candry freely and be used like common bricks%

.2 !$se #tudy

Auro$ille# 4ondicherry'ince the beginning of Auro$ille# $arious e5periments ha$e been made withearth building# with mi5ed results% The creation of the Auro$ille (arth*nstitute 0A6(*2 started a new era in earthen architecture% The reason whyAuro$ille was chosen for case study was because it has become one of theworld7s top centers for e5cellence in earthen architecture# working in 89

countries to promote and transfer knowledge in earth architecture% C'() isthe most used techni,ue in Auro$ille% Auro$ille has a number of buildingsbuilt using C'()%

.3 An$lysis The earth used in the construction of buildings in Auro$ille is dug out from

thelocation itself%

'trawC'()

esearch on material

4arameters• :urability

• (nergy e!ciency

• Thermal e!ciency

• ;ire resistance

• Cost e.ecti$enessCase'tudy Analysis

Conclusio



-production made on site or nearby reducing transportation costs andsa$ing

fuel and time -+rewood not re,uired limiting deforestation

<ocal management of resources

-top soil to be scraped away to unco$er subsoil-later on top soil can be put back to resulting ca$ity-land to be used for agricultural purposes

/arket opportunity

- C'() usually is cheaper then +red bricks(nergy efficiency

-re,uiring only little stabilizer 0thus little fuel for it2# embodied energyfor

1metre cube of C'() is about four times less than 1metre cube of

;irebricks educing imports

-can be produced locally by semi-skilled labor# no need to importe5pensi$e

materials or transport o$er long distances hea$y and costly materials%

)$ble .3.1 !om"$risons bet*een !#&' $nd other building m$teri$ls +#ource,

htt",--***.e$rth$uroville.com/

&mbodied energy "er metre cube of *$ll

C'() wall =81 /J>cubic metre?iln ;ired bricks @89= /J>cubic metreCountry +red bricks =89 /J>cubic metre

C'() consumes 11 times less energy than country +red blocks and fourtimes less than wire cut bricks%

0ollution emission "er cubic metre of m$teri$l

C'() wall B%8D kg of CE@ > cubic metre?iln ;ired bricks @= kg of CE@ > cubic metre

Country +red bricks =B@%D kg of CE@ > cubic metre

C'() is polluting thirteen times less than the country +red bricks and si5 times lessthanwire cut bricks%



!ost

C'() wall0@B cm thick2 Country +red brick wall0@@cm thick2

s%8#F=D per cubic metre s%B#@B8 per cubic metres%D8= per s,uare metre s%8B per s,uare metre

A +nished metre cube of C'() masonry is always 19-@F cheaper than country +re bricks%

.4 Other $dv$nt$ges

Thermal comfort

-e5posed block walls regulate indoor humidity# helping you achie$e thermalcomfort through the year

-with proper planning and design# less energy needed to achie$e acomfortable indoor en$ironment-earth buildings pro$en o$er decades to be healthier than concrete buildings%

'trength of load bearing structures

-C'() can be used for load bearing structures as they are strong enough to bear B Hoors without concrete column

-arches# $aults# domes can replace concrete beams# slabs# thus bringing o$era cost lower than con$entional structures%

-C'() need not necessarily be plastered'ocial acceptance

-it has demonstrated its ability to adapt to $arious needs from low income to

high income# go$ernment buildings# multi-storey# etc-creati$e and aesthetically pleasing designs could be made-natural# e5posed# high ,uality +nishes could be gi$en to the surfaces%

Job creation

-unskilled# unemployed people get a chance to learn new skills# gaining employment and social $alues%

igure (rrorI o te5t of speci+ed style in document%1, !#&' construction source,htt",--***.e$rth$uroville.com



.1 #tr$* '$le

'traw is a natural +ber obtained as a byproduct from agriculture% *t is the stalk0plant structure between root crown and grain head2 of grasses like rice# wheat#sorghum that ha$e high tensile strength% *t is composed of cellulose# hemicellulose li,uid and silica% *t is non- rigid# He5ible and easy to work with% *t isproduced by the natural# non-polluting process of photosynthesis& hence use of this in construction is ob$iously an en$ironmental friendly method% *t is eco-friendly in production# function# operation# maintenance and reconstruction%*ndia# where agriculture is the main source of income# straw can be producedtremendously%'traw bale is made by compressing a bundle of straw to a s,uare> rectangular>circular shape using wire or twines% The density of the bale can $ary with thetype of grains# moisture le$el in the straw# its degree of compaction% )aledimensions $ary as per circumstances but standard sizes used are FFmm 5B9Fmm 5 89Fmm or 9Bmm 5 11=mm 5 BFFmm% A straw bale wall is =9 lessweight than e,ui$alent brick wall and =@ less than e,ui$alent concrete brickwall% 3hen bundled together into a bale# it becomes a solid block that is highlyresistant to decomposition% 3hen assembled together and co$ered with a plasterskin# straw bales make a beautiful# strong# energy-e!cient and ecologicallysound structure%Kowe$er construction using straw bale has to be restricted in places where thereis e5cess moisture in order to protect against the attack of termites and pests%'traw bale construction will be durable only where there are stringent moistureresistant conditions%

;igure &rror No te6t of s"eci7ed style in document.@" 'traw )ale construction

Lsource" http">>www%pajaconstruction%comM.2 An$lysis

A$ailability-)ecause it is an agricultural by-product it is locally a$ailable% Thustransportation costs can be reduced to an e5tent.

;ire resistance-straw bale tightly packed hence good resistance against +re due to lack of o5ygen



Thermal insulation- Thick straw bale wall has good thermal insulation# because there createsan insulating gap between internal and e5ternal walls% Thus there is aresistance in heat How through the wall% ice straw is the most e!cientinsulating material

• 'ound insulation- 'traw is +brous in nature that resists tra$el of sound wa$es# thuscontrolling noise%

• 'tructural capacity- <oad bearing straw bales can withstand up to 8 storeys while framedstructures ha$e great stability%

• Cost e.ecti$e-materials used to create bale walls are less e5pensi$e than other commonwall systems% 3all raising is easily done with bales# thus cutting down onlabor costs%

igure (rrorI o te5t of speci+ed style in document%3, source,

htt",--***.ijmer.com

8. !onclusion

)uilding with earth is de+nitely an appropriate and cost and energy e.ecti$etechnology that will pro$e to be an eco-friendly material in future also whilebuilding with straw bale is a method that has the potential to be one of thebetter construction techni,ues in future% 'traw bale construction will be e!cientwhere there is proper moisture resistance% (.ecti$eness of any design andconstruction technology depends on the conte5t of time# skill a$ailable# location#function and a$ailable fund% C'() and straw bale can be e.ecti$ely used inbuildings# if there are stringent ,uality control systems and performanceguarantee%

9. :eferences

1% auroville earth institute% 0@F1B# december 2% etrie$ed fromhttp">>www%earthauro$ille%com>compressed-stabilised-earth blocksNen%php%4. com"ressed stabilied earth blocks% 0@F1B# december 2% etrie$ed fromhttp">>www%slideshare%net%5. 'traw )ale in construction of building and its future in *ndia% 0@F19# july 1F2%etrie$ed from



http">>www%ijmer%com>papers>$ol@Nissue@>)3@@B@@B@=%pdf 6. "aja construction% 0@F19# august 12% etrie$ed from http">>pajaconstruction%com>straw-bale-e5pert-blog>7 % Straw bale construction as an economic environmental building alternative8Acase study % 0@F19# july 1F2%etrie$ed from

http">>arpnjournals%com>jeas>researchNpapers>rpN@FF>jeasN11FN@=9%pdf%9. sustainable building materials in kerala % 0@F1B# december 1F2% etrie$ed fromhttp">>dyuti%cusat%ac%in>5mlui>bitstream>handle>purl>B=89>sustainable@Fbuildings@Fmat



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Dissertation aparna 19.10.15.docx