Cons uc ion and Building Ma e ials 419 (2024) 135435
A ailable online 20 Feb ua y 2024
0950-0618/© 2024 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY license (h p://c ea i ecommons.o g/licenses/by/4.0/).
Cha ac e iza ion and pe o mance o building composi es made om
gypsum and woody-biomass ash was e: A p oduc de elopmen and
applica ion s udy
Manuel Alejand o Ped e˜
no-Rojas
a
, C´
esa Po as-Amo es
a
, Paola Villo ia-S´
aez
a
,
*
, Ma ía
Jesús Mo ales-Conde
b
, Inˆ
es Flo es-Colen
c
a
TEMA Resea ch G oup, ETS Edi icaci´
on, Uni e sidad Poli ´
ecnica de Mad id, A . Juan de He e a 6, Mad id 28040, Spain
b
Depa amen o de Cons ucciones A qui ec ´
onias I, ETS A qui ec u a, Uni e sidad de Se illa, A . Reina Me cedes 2, Se ille 41013, Spain
c
CERIS, Depa men o Ci il Enginee ing, A chi ec u e and En i onmen , IST, Uni e sidade de Lisboa, A . Ro isco Pais, Lisbon 1049-001, Po ugal
ARTICLE INFO
Keywo ds:
Plas e
Recycling
Ci cula economy
Wood
Ash
Cons uc ion
ABSTRACT
The aim o his s udy is o explo e he po en ial o using biomass-ash was e as a seconda y aw ma e ial o
building composi es. The was e is gene a ed by a he mal powe plan ha bu ns woody biomass and would
o he wise be disposed o in land ills. The s udy in es iga es he physical and mechanical p ope ies o gypsum-
based composi es con aining di e en p opo ions o biomass-ash was e and compa es hem wi h he e e ence
and egula o y documen s. The s udy also p oposes some possible building applica ions o he op imal com-
posi e and e alua es i s pe o mance h ough simula ions. The esul s indica e ha adding up o 25% wood ash
can imp o e he mechanical s eng h o he composi es, exceeding he e e ence and minimum equi emen s.
The p oposed building applica ions using he new composi e each a educ ion in he en i onmen al impac and
an imp o emen in he ene gy e iciency o he building en elope.
1. In oduc ion
The cons uc ion indus y is he single la ges global consume o
esou ces and aw ma e ials [40]. This is no he only nega i e impac ,
bu also, in mos cases, he cons uc ion p ocess comes om
non- enewable esou ces, and uses conside able amoun s o ene gy,
since some o he ma e ials a e subjec ed o ene gy-in ensi e
manu ac u ing p ocess, along wi h he signi ican olume o emissions
o all ypes o pollu an s. The e o e, se e al esea che s ha e claimed
ha buildings a e esponsible o accoun ing o a ound 40% o o al
ene gy use, consume 12% o he wo ld’s d inkable wa e , and p oduce
almos 40% o global ca bon dioxide emissions in Eu ope [12].
This si ua ion is expec ed o wo sen, as he wo ld’s consump ion o
aw ma e ials is se o nea ly double by 2060 as he global economy
expands and li ing s anda ds ise [26]. In his way, he cons uc ion
indus y needs o change and mo e owa d o he ac i i ies ha p omo e
posi i e impac s on socie y and he en i onmen [13].
In he a emp o p o ide an al e na i e o he adi ional and
dominan model ea u ed a consuming and disposing o esou ces, he
Ci cula Economy (CE) ini ia i e eme ges o ansi ioning o a mo e
e icien ci cula model d i ing he esea ch owa d he minimizing,
ecycling, and eusing o was e s eams [2,25]. In his way, CE has he
ul ima e goal o e aining ma e ials and esou ces ci cula ing a hei
highes alue wi hin plane a y bounda ies, in a way ha addi ional
na u al esou ces a e unnecessa y o p oduce goods, and he disca ded
ma e ials a e no iewed as was e [22].
Since 2015, he Eu opean Commission has adop ed se e al Ci cula
Economy Ac ion Plans in o de o help s imula e Eu ope’s ansi ion o a
ci cula economy, by p oposing a global alliance o iden i y knowledge
and u u e challenges in ad ancing owa ds a global ci cula economy
[17].
In his ega d, de eloping new egula ions and policies, dec easing
he exploi a ion o na u al esou ces, op imizing p oduc ion p ocesses,
es ablishing comme cial compe i i eness o eco e ed and ecycled
ma e ials, as well as diminishing he use o na u al esou ces h oughou
he en i e cons uc ion p ocess a e ac ions aligned wi h CE ha need o
be conside ed by go e nmen agencies, p i a e companies, and
esea che s.
In his con ex , in es iga ing he po en ial o educe ma e ial used in
his sec o , by consuming seconda y o was e p oduc s, will signi ican ly
* Co esponding au ho .
E-mail add ess: [email p o ec ed] (P. Villo ia-S´
aez).
Con en s lis s a ailable a ScienceDi ec
Cons uc ion and Building Ma e ials
jou nal homepage: www.else ie .com/loca e/conbuildma
h ps://doi.o g/10.1016/j.conbuildma .2024.135435
Recei ed 30 Oc obe 2023; Recei ed in e ised o m 22 Janua y 2024; Accep ed 9 Feb ua y 2024
Cons uc ion and Building Ma e ials 419 (2024) 135435
2
impac global aw ma e ial consump ion and educe he p essu e on
na u al esou ces, a o ing he ansi ion owa ds CE [22].
Fo his pu pose and aiming o educe he cons uc ion indus y’s
impac s, he use o eco e ed and ecycled ma e ials o p oduce new
cons uc ion p oduc s has a isen in he pas decade. Cu en s a is ics
show ha he EU’s ci cula i y a e has isen du ing he las en yea s,
om 10.8% in 2010 o 11.7% in 2021 [18]. A highe ci cula i y a e
alue indica es a highe p ima y aw ma e ials subs i u ion by second-
a y ma e ials. Howe e , his a e is well below he a ge se by he EU
o 2030 (24.3%) and he e o e new op ions o was e eco e y and
ecycling should be encou aged.
Cu en ly, as a ecycling s a egy, building p oduc s inco po a e a
ac ion o ecycled ma e ials such as conc e e, glass, plas ics, i es,
wood, among o he s, in an e o o eco e ing wha is o en disca ded.
In his way, wi h he e e -inc easing need o educe he dependency on
ossil uel combus ion and lowe g eenhouse gas emissions, he use o
biomass o hea and elec ici y p oduc ion ha e inc eased subs an ially,
esul ing in an inc ease o ash was e gene a ion. Almos 500 million ons
o biomass ash a e p oduced pe yea wo ldwide, and o he mos pa
(a ound 70%) a e disposed o in land ills [14] and he es is used o soil
pH co ec ion and/o e iliza ion o o inco po a ion in cemen i ious
ma e ials o building and oad cons uc ions.
2. Li e a u e e iew
Many esea che s ha e ocused on he addi ion o was e ashes as
al e na i e aw ma e ial o p oduce building ma e ials and p oduc s.
Among hese s udies, hose inco po a ing ashes om he ag icul u al,
wood o o he indus ial sec o s can be highligh ed (Table 1).
Rega ding he was e om he ag o-indus ial sec o , ashes om he
p oduc ion o oli es, ice husk, and palm oil ha e been widely used o
building applica ions showing lowe densi ies and imp o ed he mal
p ope ies in he de eloped composi es [15,31]. In pa icula , up o 8%
o ice husk ash can be inco po a ed in gypsum keeping an adequa e
wo kabili y, educing he densi y and imp o ing he he mal p ope ies
o adi ional building plas e s [28]. In addi ion, a good i e eac ion was
obse ed when oli e pomace o palm oil ashes we e used o de elop
building panels and boa ds [10,30]. A high wa e e en ion capaci y was
achie ed when ashes om he palm oil ex ac ion we e used o manu-
ac u e boa ds con aining clay, gypsum and e miculi e [10].
O he au ho s analyzed he iabili y o inco po a ing o he indus ial
ashes in building ma e ials o imp o e some p ope ies [27,34,35,41].
Low he mal conduc i i y coe icien s and highe sound-abso bing
p ope ies we e obse ed by Lei a e al. [29] when ly ash om coal
combus ion was inco po a ed in a gypsum ma ix, keeping simila me-
chanical p ope ies o o he ligh weigh comme cial gypsum p oduc s.
By con as , lowe mechanical p ope ies we e achie ed when 60% o
he na u al gypsum was subs i u ed by whi e slag ash [9], bu hey we e
all abo e he minimum se by he egula ions. Despi e he lowe me-
chanical esis ances, a subs an ial imp o emen o he i e eac ion was
obse ed when highe amoun o slag ash was inco po a ed.
Fu he mo e, se e al publica ions we e ound inco po a ing wooden
biomass ash in building ma e ials. Foˇ
e al. [19] explo ed he e ec o
eplacing 50% o wooden biomass ash in lime plas e s o be applied as an
ex e io su ace laye in buildings. A conside ably imp o emen on he
mechanical p ope ies was obse ed, whe eas he hyg ic p ope ies we e
kep simila o he e e ence. In addi ion, be e mechanical imp o e-
men s (a ound 17% compa ed o he e e ence) we e also obse ed
when 20% o wooden biomass ash was inco po a ed in cemen [21]. Foˇ
e al. [20] also explo ed he iabili y o using wooden biomass ash as
supplemen a y cemen i ious ma e ial, by eplacing up o 30% o coal ly
ash in he ab ica ion o blended cemen s.
Table 1 summa izes he key indings om he li e a u e e iew
conduc ed o de e mine wha has been p e iously in es iga ed on he
inco po a ion o ash was e in building ma e ials. In gene al, he indings
ob ained by he s udies shown in Table 1 ha e simila o sligh ly be e
p ope ies han con en ional ones. They a e cha ac e ized o ha ing:
•highe mechanical pe o mance;
•low he mal conduc i i y;
•good i e eac ion; and
•imp o ed acous ic insula ion.
Based on hese indings some au ho s ha e explo ed he iabili y o
combining a mix o a ious ashes. Resul ing in simila p ope ies han
he ones abo e, such as highe wa e e en ion [38], accep able and
imp o ed mechanical p ope ies [8,38] and good he mal and i e e-
ac ion [8].
Howe e , i is necessa y o s udy he inco po a ion o o he ypes o
biomass ashes in gypsum since, ha ing a e y di e en composi ion, i
will p o ide di e en p ope ies [38]. In his sense, despi e he
nume ous in es iga ions ound adding ashes, no p e ious in es iga ions
ha e been ound inco po a ing biomass ash om wood in plas e
composi es.
Gi en he abo e backg ound, his wo k aims o con ibu e o he
de elopmen o sus ainable ma e ials by de eloping a gypsum ma e ial
con aining woody biomass was e o imp o e he cha ac e is ics o eg-
ula gypsums. The e o e, he objec i e o he s udy is o assess he me-
chanical beha io o gypsum composi es inco po a ing woody biomass
ash was e and analyze he possible building applica ion.
3. Ma e ials and me hods
3.1. Ma e ials
The ma e ials used o his s udy we e: gypsum, woody biomass ash,
and wa e :
•Gypsum: The gypsum used is high pu i y gypsum named Ibe yola E-
30/E-35, which is complian wi h he s anda d UNE-EN 13279-1 [4]
and classi ied as ype A by he Eu opean classi ica ion. I was p o-
ided by Placo Sain -Gobain.
•The biomass ash shown in Fig. 1 was collec ed om a dis ic hea ing
powe plan - ueled by woody biomass - placed in M´
os oles (Spain).
I s eal densi y, de e mined by Mas e size equipmen , was 2.4108
g/cm
3
, wi h a coe icien o a ia ion o 0.0564%. The pa icle size
dis ibu ion o he ash was also ob ained, and i is ep esen ed in
Fig. 2. The chemical composi ion o he biomass ash was ob ained by
a PANaly ical XRD equipmen , as i is shown in Fig. 3, we e he majo
componen s we e g aphi e and qua z ollowed by po landi e and
calci e.
•Wa e : Regula wa e om Canal de Isabel II was used.
3.2. Expe imen al plan
The expe imen al plan was de eloped ollowing he nex phases:
1. Samples’ p epa a ion;
2. Physical and mechanical cha ac e iza ion;
3. Raw ma e ial consump ion and selec ion o bes composi e;
4. P oposal o building applica ions and u he cha ac e iza ion.
3.2.1. Samples’ p epa a ion
The samples’ p epa a ion ollowed he s anda d UNE-EN 13279–1
[4], and i began wi h he elabo a ion o he e e ence (wi hou any
was e) and con inued wi h he p epa a ion o composi es inco po a ing
di e en pe cen ages o ash was e (5%; 10%; 15%; 20% and 25%) o e
he weigh o gypsum. A o al o six di e en composi es we e analyzed
(Table 2). Acco ding o he s udies ound in he li e a u e e iew
(Table 1) and he supplie ’s ecommenda ion, he wa e /gypsum (w/g)
a io used in his esea ch was 0.8.
M.A. Ped e˜
no-Rojas e al.
Cons uc ion and Building Ma e ials 419 (2024) 135435
3
Table 1
Key indings o p e ious esea ch wo ks inco po a ing was e ashes in gypsum composi es.
Was e
o igin
Re e ence Was e ash % was e Ma ix Building applica ion Key indings
Ag o-
indus ial
Vilches e al. [38] Biomass ash: Oli e
pomace and ice-husk
69% pomace. 1% ice-
husk. 1% glass ibe
Gypsum Insula ing pla es wi h i e- esis ance
p ope ies
The de eloped p oduc p esen s simila i e esis ance and physical and
mechanical p ope ies o o he comme cial p oduc s used in passi e i e
p o ec ion in buildings and indus ial ins alla ions
Lei a e al. [30] Biomass ash: oli e oil
ex ac ion p ocess.
60% ash.
9.5% e miculi e 0.5%
ibe
Gypsum Low-densi y panels (800 kg/m3) o
in e nal pa i ions in buildings
Good i e esis ance due o hei high-wa e e en ion capaci y (simila o
gypsum plas e boa d). I did no show no iceable de o ma ion, c umbling, o
c acking.
Alba e al. [8] Fly ash om oli e oil
ex ac ion
50% ash. Gypsum, clay, and
cemen wi h ibe s
In e nal wall pa i ions o limi ed
load-bea ing p ope ies
Low densi y. Resis ance s eng h dec eases wi h mo e addi ion o ash
Ama e al., [10] Fly ash om oil palm
ex ac ion
<20% ash Gypsum Wallboa d use o on walls, ceilings,
o pa i ions
biomass ash panel boa d can e ain mo e han 2 h i e esis ance in s anda d
condi ions o oom empe a u e by i e labo a o y and panels showing a
comp essi e s eng h o 3.54 MPa
Lei a Aguile a y Del
Río Me ino (2014)
Rice husk ash 8% ash Gypsum Suspended ceiling Reduced densi y and imp o ed he mal beha io and mechanical p ope ies
keeping a good wo kabili y.
O he
indus ies
Rod íguez e al.
(2009)
Ladle u nace slag 30% Cemen Mason y mo a s Highe mechanical p ope ies a e achie ed when highe % o ash is inco po a ed.
Lei a e al. [29] Fly-ash om coal
combus ion
60% ash Gypsum
Ve miculi e
Fib es
Fly-ash boa ds Good physical and mechanical p ope ies. Sound-abso bing ma e ial. Low
he mal conduc i i y and high i e eac ion.
Rahamma e al.
(2015)
Fly-ash 30% Cemen Cemen binde s Highe amoun o ly ash equi ed g a e wa e o keep he wo kabili y and
highe se ing ime.
Z´
alesk´
a (2018) Sewage sludge 30% ash Cemen Lime and cemen binde s The inc ease in po osi y up o 6% and dec ease in comp essi e s eng h up o 3%
we e sa is ac o y.
Alonso e al. [9] Whi e slag 60% ash Gypsum Indoo pa i ions o p o ec ion in
a eas wi h agg essi e he mal
equi emen s
Mechanical esul s dec eased compa ed o e e ence. Be e beha io be o e i e.
Kua and Choo [27] Biocha -coa ed pelle s 0.38% Lime Indoo lime plas e s The pape e alua es he po en ial o emo ing CO
2
when biocha is used and
agg ega e in indoo plas e s.
Wood Foˇ
e al. [19] Wooden biomass ash 50% ash Lime Ex e io supe icial laye Mechanical pe o mance imp o ed conside ably, and he es o he esul s
(hyg ic and po osi y) we e kep simila o he e e ence in all cases.
Foˇ
e al. [21] Wooden biomass ash 70% ash Cemen Non-s uc u al conc e e Highe mechanical esis ance when up o 30% o he cemen was eplaced
Foˇ
e al. [20] Wooden biomass ash 30% ash Cemen Cemen mo a s Wooden biomass ash can be used as supplemen a y cemen i ious ma e ial and
subs i u e up o 30% o coal ly ash.
M.A. Ped e˜
no-Rojas e al.
Cons uc ion and Building Ma e ials 419 (2024) 135435
4
Samples we e le o ha den o se en days a oom empe a u e in
he labo a o y wi h a empe a u e o 23 ±2◦C and ai ela i e humidi y
a ound 50 ±5%. On he se en h day, hey we e in oduced and kep in
he o en a 40ºC o 24 h be o e es ing.
3.2.2. Physical and mechanical cha ac e iza ion
Expe imen al es s in he labo a o y we e conduc ed aiming o
de e mine he physical and mechanical p ope ies o he composi es.
The ollowing es s we e ca ied ou : d y bulk densi y, supe icial
ha dness, lexu al s eng h, comp essi e s eng h; bonding s eng h, and
he mal conduc i i y es , ollowing he UNE EN 102042 [7], UNE EN
13279–2 [3] and ASTM D5334–08 [11] s anda ds.
Th ee specimens 4×4x16 cm
3
o each composi e we e es ed o d y
bulk densi y, supe icial ha dness, lexu al and comp essi e s eng h (a
o al o 18 specimens we e es ed in each es ). Fo his, a Gibe ini
Eu ope3000HR scale was used o he bulk densi y, a Sho e C du ome e
o he supe icial ha dness and he uni e sal es ing machine Ibe es
Au o es 20 was used o he lexion and comp ession s eng h.
Fo he bonding es , each composi e –in esh s a e– was laye ed
o e a ce amic-based suppo c ea ing a coa ing o 1 cm hick. Then,
nine ci cula segmen s we e ma ked on he su ace o each composi e (a
o al o 54 samples), and me allic discs wi h a diame e o 5 cm we e
ixed on op. Then, a Dyna es DTH 500 de ice was used o pe o m he
es and eco d each alue ollowing he UNE EN 13279–2 [3] s anda d.
To ob ain he he mal conduc i i y coe icien , one specimen o
6×6x3 cm
3
pe composi e (a o al o 6 samples) was de eloped and
es ed (3 measu emen s) using an ISOMET 2114 ansien equipmen o
measu e he he mal conduc i i y coe icien unde labo a o y condi-
ions, ollowing he p ocedu e de ined by ASTM D5334–08 [11].
Resul s we e eco ded and he mean alue was achie ed o each
composi e. Resul s we e compa ed wi h he e e ence sample and wi h
he minimum alues se by he s anda ds.
Finally, in o de o jus i y he ob ained esul s, SEM analysis o he
composi es was conduc ed using a FEI TENEO, an ul a-high- esolu ion
analy ical Scanning Elec on Mic oscope.
3.2.3. Analysis o he consump ion o na u al gypsum and selec ion o
composi e
In his sec ion, he mos sus ainable composi e was selec ed consid-
e ing he en i onmen al pe o mance (highe was e con en ) and me-
chanical beha io (good mechanical p ope ies ul illing gypsum
composi es egula ions).
Fo his, an analysis o he aw ma e ial consump ion was explo ed
ollowing he me hod used by p e ious esea ch wo ks [32,36,39]. The
educ ion in pe cen age o he consump ion o na u al gypsum
compa ed o he e e ence sample was calcula ed o all he composi es.
A e ha , he en i onmen al bene i s o he achie ed gypsum educ ion
was calcula ed using he Global Wa ming Po en ial (GWP) and
Embodied Ene gy (EE) impac s acco ding o ITeC-BEDEC da abase [24].
3.2.4. P oposal o building p oduc and u he cha ac e iza ion
A e selec ing he mos sui able composi e, a new building p oduc
o in e io coa ings in buildings we e expe imen ally and nume ically
e alua ed. In a i s phase, a labo a o y p ocedu e was conduc ed, in
which wo 60×40×1.5 cm
3
panels we e de eloped using he selec ed
composi e and he e e ence composi ion and we e u he es ed
ega ding hei mechanical esis ance o bending ollowing UNE-EN
12859 [6].
A e ha , ying o e alua e o he comme cial panel dimensions,
ini e elemen s models we e elabo a ed, and using he b eaking es
esul s abo e desc ibed o calib a e hem, a mechanical simula ion o a
bending es was conduc ed using SAP2000 so wa e. On i , h ee
di e en panel dimensions we e e alua ed o bo h composi ions:
60×40×1.5 cm
3
( he one es ed in labo a o y), 60×60×1.5 cm
3
(s an-
da d size o suspended ceiling iles) and 60×120×1.5 cm
3
( ypical in
con inuous ceilings pieces). The achie ed alues we e compa ed and
checked wi h he s anda d equi emen s o each case.
3.2.5. P oposal o building p oduc and ene gy e iciency
A building ene gy simula ion was also done using Design Builde
so wa e o e alua e he ene gy e iciency po en ial when ecycled
Fig. 1. Woody biomass ash (WBA).
Fig. 2. Pa icle size dis ibu ion o he woody biomass ash (WBA).
Fig. 3. X- ay di ac ion ob ained o he woody biomass ash (WBA).
Table 2
Composi e’s composi ion o 1 kg o gypsum powde .
Composi e Gypsum
[g]
Wa e
[g]
W/G
a io
Wooden biomass ash (WBA)
[g]
Re 1000 800 0.8 0
WBA5 1000 800 0.8 50 (5 w %)
WBA10 1000 800 0.8 100 (10 w %)
WBA15 1000 800 0.8 150 (15 w %)
WBA20 1000 800 0.8 200 (20 w %)
WBA25 1000 800 0.8 250 (25 w %)
M.A. Ped e˜
no-Rojas e al.
Cons uc ion and Building Ma e ials 419 (2024) 135435
5
ma e ial is applied o a e e ence building. The simula ion model
de eloped will se e o quan i y he ene gy sa ings in ol ed in
including he same ecycled ma e ial in di e en building applica ions
(gypsum plas e , lamina ed gypsum boa d, and gypsum block) eplacing
adi ional ma e ials.
Fo his pu pose, a i ual e e ence building has been de eloped
wi h ep esen a i e cha ac e is ics o a la ge pa o he buildings buil
in Spain. The e e ence building includes he mos common cons uc ion
cha ac e is ics in Spain [23] and he egula o y equi emen s es ab-
lished in he Technical Building Code [37]. All de ails o he cons uc-
ion model, as well as he se ings o he ene gy simula ion used, can be
consul ed in he a icle p e iously published by Po as-Amo es e al.
[33]. In his sense, he composi ion o he açade o he building has been
sligh ly modi ied o adap he case s udy o he new ecycled ma e ials
included in his esea ch and ca y ou he compa a i e s udy.
The building has been i ually loca ed and simula ed in a cold
clima e (So ia) and a wa m clima e (Se ille), which ep esen he
clima e a iabili y in Spain, in o de o s udy he po en ial o he ecy-
cled ma e ials in di e en clima e condi ions. Acco ding o he K¨
oppen
clima e classi ica ion, So ia co esponds o a empe a e oceanic clima e
(C b) and Se ille o a ypical Medi e anean clima e (Csa).
Fig. 4 shows he geome y o he simula ion model de eloped. The
e e ence building has ou loo s wi h a ee heigh o 2.7 m each and
he e a e no loo s below g ound le el. Each loo is made up o six equal
dwellings o 110 m
2
each, esul ing in a o al use ul a ea o 2640 m
2
in
he building. The o al açade a ea is 1484 m
2
while he glazing a ea is
287 m
2
(20% o he o al).
4. Resul s and discussion
4.1. Physical and mechanical cha ac e iza ion
The esul s o he physical and mechanical es s pe o med o he
composi es’ cha ac e iza ion a e shown in Table 3.
The ob ained esul s o he d y bulk densi y, wi h unce ain y, a e
ep esen ed in Fig. 5. As shown in he g aph, samples wi h WBA ha e
sligh ly highe bulk densi y compa ed o he e e ence wi hou any ad-
di ions. The sample wi h he highes densi y alue was WBA20, wi h
a ound +21% highe densi y han he e e ence sample, +12% highe
han WBA5 and +7% ela ed o WBA10 and WBA15 composi es. On he
o he hand, WBA25 composi e expe ienced a d op in densi y o 10%
compa ed o WBA20 being only +9% highe han he e e ence sample.
Also, i should be no ed ha none o he composi es can be conside ed
ligh weigh composi es as he bulk densi y su pass 0.8 g/cm
2
in all cases
[1].
Fig. 6 shows he supe icial ha dness o each composi e. Low amoun
o was e addi ions –WBA5 and WBA10- esul in simila o e en lowe
supe icial ha dness han he e e ence (−11% o WBA10 and −5% o
WBA5). By con as , when mo e han 10% o WBA is added, highe
supe icial ha dness is eco ded, eaching a ound +11% o inc ease o
he WBA25 composi e and +4% o he WBA20 composi e, compa ed o
he e e ence sample. All o he achie ed alues a e abo e he minimum
alue −45 Sho e C uni s- equi ed by he egula ion [3,16].
Rega ding he esul s o lexu al s eng h (Fig. 7), all he composi es
showed a dec ease compa ed o he e e ence mix u e. In his case,
WBA10 composi e p esen ed he lowes alue wi h a dec ease by up o
−49% o WBA25 composi e wi h a dec ease o −46%. On he o he
hand, WBA5 and WBA15 esul s expe imen ed a d op o -37% and
−38% espec i ely compa ed o he e e ence mix u e. In he middle,
WBA20 composi e showed a dec ease o −40% acco ding o he e e -
ence composi e alue. Despi e hese d ops in esis ance, he alues al-
ways emained abo e he minimum alue −1 MPa- equi ed by he
egula ion UNE-EN 13279–1 [4]. These esul s a e in line wi h p e ious
esea ch wo ks. In pa icula , a educ ion in he lexu al s eng h was
also obse ed by Alonso e al. [9], when whi e slag ash was inco po a ed
in gypsum composi es.
Simila ly, he same endency was obse ed o he alues ob ained in
he comp essi e s eng h es (Fig. 8), dec easing up o 49% - also o he
WBA10 composi e -, when compa ed o he e e ence alue (4.08 MPa).
In his case, WBA15 and WBA25 composi es showed simila d ops in
esis ance, a ound −40% compa ed o he e e ence mix u e. Howe e ,
i should be no ed ha hey all emained abo e 2 MPa, which is he
minimum equi ed by he s anda d UNE-EN 13279–1 [4,5]. Excep o
he e e ence, he bes pe o ming composi e was WBA20, achie ing
5.58 MPa (33.7% lowe han he e e ence).
Fig. 9 p esen s he esul s ob ained o he bonding s eng h o he
composi es, ob ained using he adhesi e pull-o es , which a e simila
o hose o he e e ence. The composi es wi h highe bonding s eng h
we e WBA15 and WBA20 (+8.33% and +16.7%, espec i ely i
compa ed o he e e ence). By con as , he composi e wi h he lowes
bonding s eng h was WBA25 (−8.3%).
Fig. 10 shows he esul s ob ained o he he mal conduc i i y
measu emen . As i can be no iced, an imp o emen o he he mal
beha io o he composi e was obse ed when he amoun o wood
Fig. 4. Building ene gy simula ion model.
M.A. Ped e˜
no-Rojas e al.

Cons uc ion and Building Ma e ials 419 (2024) 135435
6
biomass ash inc eased in he mix u e, achie ing he bes he pe o -
mance wi h 25% o WBA addi ion (WBA25) (−17.7%, i compa ed o he
e e ence alue). In his case, i mus be no ed ha no signi icance
Table 3
Resul s o he physical and mechanical es s, including coe icien o a ia ion [%].
Sample D y bulk densi y
[g/cm
3
]
Supe icial ha dness
[Sho e C]
Flexu al s eng h
[MPa]
Comp essi e s eng h
[MPa]
Bonding s eng h
[kN]
The mal conduc i i y [W/ (m⋅K)]
Re 0.988 (4.72%) 68.192 (4.63%) 3.554 (6.17%) 8.423
(5.98%)
0.300
(6.29%)
0.300
WBA5 1.071 (5.07%) 65.067
(4.87%)
2.245 (6.38%) 4.583
(6.11%)
0.288
(6.45%)
0.281
WBA10 1.121 (5.21%) 60.700
(5.19%)
1.843 (6.64%) 4.083
(6.29%)
0.300
(6.78%)
0.278
WBA15 1.121 (5.40%) 68.700
(5.38%)
2.209 (7.11%) 5.032
(6.86%)
0.325
(7.12%)
0.262
WBA20 1.202 (5.68%) 70.900
(5.41%)
2.133 (6.98%) 5.584
(6.70%)
0.350
(7.33%)
0.257
WBA25 1.084 (5.73%) 75.867
(5.59%)
1.907 (7.19%) 5.195
(7.01%)
0.275
(7.41%)
0.247
Fig. 5. D y bulk densi y esul s o he composi es wi h coe icien o a ia ion.
Fig. 6. Supe icial ha dness esul s o each composi e wi h coe icien
o a ia ion.
Fig. 7. Flexu al s eng h esul s o each composi e wi h coe icien
o a ia ion.
Fig. 8. Comp essi e s eng h esul s o each composi e wi h coe icien
o a ia ion.
Fig. 9. Bonding s eng h esul s o each composi e wi h coe icien
o a ia ion.
Fig. 10. The mal conduc i i y coe icien esul s.
M.A. Ped e˜
no-Rojas e al.
Cons uc ion and Building Ma e ials 419 (2024) 135435
7
s anda d de ia ion was obse ed o any composi es when he h ee
measu emen s alues we e e alua ed. An imp o emen in he he mal
conduc i i y was also ound by p e ious esea ch wo ks inco po a ing
ashes om he oli e and ice p oduc ion, which claimed lowe he mal
conduc i i y coe icien s compa ed o he e e ence [10,28,30].
Fig. 11 shows he ela ion be ween he d y bulk densi y and he
he mal conduc i i y o each composi e. Resul s show ha he obse ed
d op on he he mal conduc i i y o he plas e was only explained by
he inc ease on he pe cen age o WBA added o he composi ions.
Howe e , no o all he plas e s, he d op on he d y bulk densi y did no
ollow he same endency o he he mal beha io .
Finally, o jus i y some o he no iced mechanical beha io on he
plas e s, SEM analysis was conduc ed. Fig. 12 p esen s wo SEM images
aken om WBA25 plas e . As in can be seen, he addi ion o wood
biomass ash inc eases he po osi y o he plas e , imp o ing i s he mal
pe o mance. Fu he mo e, he lack o adhe ence be ween he WBA
pa icles and he gypsum ma ix could jus i y he d op on he mechan-
ical p ope ies o he new composi es.
4.2. Analysis o he consump ion o na u al gypsum
The addi ion o WBA pa icles o he gypsum ma ix means a
educ ion on he consump ion o na u al gypsum on he plas e s. Thus,
Table 4 p esen s he educ ion on he consump ion o na u al gypsum o
a kg. o each composi e and i s implica ion in e ms o GWP and EE [24].
As i was expec ed, he highes educ ion was ob ained o he
WBA25 composi e, achie ing a educ ion o −0.012 kg CO
2
eq. and
−0.131 MJ o p ima y ene gy. This ac jus i ies he highes con ibu-
ion o he gypsum powde in he en i onmen al impac o he com-
posi es, imp o ing hem when was e is added as agg ega e o he
mix u es ( educing he amoun o gypsum used).
4.3. Discussion on building applica ions – mechanical pe o mance
As i was men ioned, he de eloped composi es we e used o he
gene a ion o gypsum pla es o he cladding o buildings. Thus, on a
i s phase, Re e ence and WBA25 pla es (60 ×40×1.5 cm
3
) we e p o-
duced and es ed in labo a o y, as i is shown in Fig. 13. In his p o-
cedu e, he pieces we e submi ed o a bending s eng h es , eaching
1.12 and 0.74 MPa espec i ely.
Conside ing he bending s eng h es s esul s, a e he labo a o y
b eakage, a nume ical ini e elemen simula ion o he bending s eng h
es o he pla es was conduc ed using SAP2000 so wa e. To do i , h ee
di e en pla es leng h we e es ed: 40, 60 and 120 cm (Fig. 14). As i is
shown in Fig. 15, all he simula ion passed he alues ob ained o he
ensile s eng h o he composi es. Thus, i can be concluded ha all he
de eloped composi es a e sui able o i s usage in gypsum co e ing
pla es o mul iple uses acco ding o he di e en sizes o he pieces:
suspended ceiling iles, con inuous ceiling pieces, e c.
4.4. Discussion o ene gy e iciency po en ial
Once he cha ac e is ics o he e e ence building we e de ined and
he he mal p ope ies o he ecycled ma e ial es ima ed (Fig. 10), he
se o ene gy simula ions began. To e alua e he ene gy e iciency po-
en ial o ecycled ma e ial, only he composi e wi h he bes he mal
insula ion p ope ies (WBA25) was used.
Two simula ions we e ca ied ou o each loca ion (Se ille and
So ia), one wi h he e e ence building (REF) using adi ional ma e ials
and ano he inco po a ing ecycled ma e ials (WBA25) eplacing some
adi ional ma e ials o he in e io cladding o he acade and oo .
Speci ically, he “double hollow b ick” and he “gypsum plas e ” o he
açade we e eplaced by he “plas e block wi h 25% WBA” and he
“gypsum plas e wi h 25% WBA”, espec i ely. In he same way, he
“lamina ed gypsum boa d” o he alse ceiling o he oo was eplaced
by he “lamina ed gypsum boa d wi h 25% WBA”.
Table 5 and Table 6 de ail he ma e ials used in he açade and la
oo o he e e ence building, oge he wi h he necessa y da a o he
simula ions ( hickness, densi y, and he mal conduc i i y). The cha -
ac e is ics o he ma e ials ( hickness, densi y, and he mal conduc i -
i y) ha e been ob ained acco ding o in o ma ion published by Spanish
o icial ins i u ions [37].
Bo h building elemen s inco po a e plas e ma e ials, which we e
eplaced by ecycled ma e ials in he second simula ion. The ma e ials
highligh ed in g een we e used in he i s simula ion (REF) and la e
eplaced by hose highligh ed in o ange in he second simula ion
(WBA25). In con as , he same ma e ials we e used in he basemen in
con ac wi h he g ound, in all simula ions [33]. The ecycled ma e ial
has been included in he ollowing building applica ions: gypsum plas-
e , lamina ed gypsum boa d, and gypsum block.
Be o e analyzing he esul s, i is wo h emembe ing ha ene gy
losses in a building can occu due o he ans e o hea by ansmission
h ough he enclosu e, o due o he hea ans e by ansmission in he
en elope. In he Spanish con ex , he Technical Building Code es ab-
lishes ha new buildings mus comply wi h a minimum a e o ai
changes pe hou ha mus be main ained na u ally o mechanically.
Fu he mo e, buildings always ha e wa e leakages ha depend on
mul iple a iables, such as he age o he building, he numbe o
openings, o he quali y o he execu ion o he cons uc ion elemen s.
Al hough he selec ed e e ence building is conside ed ep esen a i e
as i includes he mos common cons uc ion cha ac e is ics in Spain,
a e ca ying ou se e al p elimina y simula ions, i has been seen ha
hea ans e in he building is mainly p oduced by ai enewals.
The e o e, he po en ial o ene gy sa ings is condi ioned by he high
a e o ai enewals in he building, wi h 79% o ene gy consump ion
due o ai enewals compa ed o 21% due o hea ans e h ough he
en elope. This is mainly due o he cu en egula o y equi emen o he
Spanish Building Code [37] ha equi es pe manen en ila ion in he
building o heal h easons o he occupan s.
The e o e, i is impo an o emembe ha he ene gy sa ings po-
en ial o ecycled ma e ials will be much highe in o he buildings ha
ha e low ai enewal a es, compa ed o hose ob ained in his esea ch.
Table 7 compa es he o al sa ings in hea ing, cooling, and he sum o
bo h in he wo Spanish ci ies unde s udy.
The esul s show ha he ecycled ma e ial imp o es he ene gy e -
iciency o buildings while o e ing a second li e o an indus ial by-
p oduc . The ene gy sa ings ob ained in a s anda d Spanish building
ollowing he cu en building egula ions ange om 5% (wa m
clima e) o 3% (cold clima e), being g ea e in hea ing han in cooling in
absolu e e ms. Fo example, in So ia, he inco po a ion o ecycled
ma e ial o eplace adi ional ma e ial has led o ene gy sa ings o 1630
kwh in hea ing and 106 kwh in cooling.
Fu he mo e, he economic sa ings o educing ene gy consump ion
in cooling can each 6% (Se ille) o 15% (So ia), while in hea ing i can
each 3% (So ia) o 5% (Se ille). These alues could inc ease consid-
e ably in buildings o cons uc ions wi h low en ila ion a es, such as,
Fig. 11. Rela ionship be ween d y bulk densi y and he mal conduc i i y o
each composi e.
M.A. Ped e˜
no-Rojas e al.
Cons uc ion and Building Ma e ials 419 (2024) 135435
8
o example, in wa ehouses ha do no need en ila ion o in coun ies
exemp om egula ions ha equi e en ila ion (o wi h low
equi emen s).
Resul s om he ene gy simula ions a e applicable o a empe a e
oceanic clima e (C b) and o a ypical Medi e anean clima e (Csa),
acco ding o he K¨
oppen clima e classi ica ion. The de e mina ion o he
deg ee o ene gy e iciency o he new ecycled composi e is essen ial o
a chi ec s and enginee s o make decisions when choosing a cons uc-
ion ma e ial in he building en elope. Also, he dosages o he new
ecycle composi es acco ding o he deg ee o ene gy e iciency o he
ma e ial is in e es ing so ha manu ac u e s can ep oduce and ma ke
hese ma e ials.
The s a egy o including ecycled ma e ials in buildings o educe
ene gy consump ion p esen s g ea po en ial. I is ecommended ha
mo e esea ch is conduc ed ocused on he cha ac e iza ion o new
ecycled ma e ials as agg ega es o op imize ene gy sa ings in buildings.
In his s udy was ocused on in e nal applica ions. Fo ou doo appli-
ca ions i is ecommended o use o he binde s (cemen and lime) so ha
he ecycled ma e ials could also be applied in ou doo a eas because o
hei highe esis ance o wa e han gypsum.
5. Conclusions
The key objec i e o his s udy was o cha ac e ize and assess he
easibili y o inco po a ing biomass-ash in o gypsum composi es,
ollowing ci cula economy c i e ia. The main conclusions a e:
Fig. 12. SEM images ob ained o he Re e ence (a) and WBA25 (b) composi es.
Table 4
Resul s o he educ ion o na u al gypsum consump ion pe kg o composi e and
en i onmen al epe cussion.
Sample Reduc ion o na u al
gypsum consump ion
[w %]
Global Wa ming
Po en ial (GWP)
[kg CO
2
eq.]
Embodied
Ene gy (EE)
[MJ]
Re - - -
WBA5 2.8 0.005 0.051
WBA10 3.4 0.006 0.061
WBA15 4.7 0.008 0.085
WBA20 6.2 0.010 0.112
WBA25 7.3 0.012 0.131
Fig. 13. Panel se ing and bending s eng h es o 60 ×40×1.5 cm
3
gyp-
sum panels.
Fig. 14. Nume ical ini e elemen simula ion o he bending s eng h es o pla es wi h di e en wid h dimensions: 40, 60 and 120 cm.
Fig. 15. Compa ison o Ma e ial Tensile S eng h and Maximum Tensile S ess
in he es ed pla es wi h di e en wid h dimensions: 40, 60 and 120 cm.
M.A. Ped e˜
no-Rojas e al.
Cons uc ion and Building Ma e ials 419 (2024) 135435
9
•Compa ed o he e e ence composi e, gypsum composi es inco po-
a ing biomass-ash showed simila physical and mechanical p op-
e ies, which lexu al and comp ession s eng h alues abo e he
no m as well as g ea e supe icial ha dness.
•Since i s p elimina y es s esul s we e accep able and i inco po-
a ed he highes pe cen age o was e, he bes composi e was he
25%-was e-con aining sample.
•I was iable o use he new composi es o he gene a ion o new
eco-e icien gypsum pla es. I s usage means a educ ion on he
en i onmen al impac o he ma e ial (up o 7.3%) and an
imp o emen on he ene gy e iciency o he building (up o 5%).
•SDGs such as 8, 9, 11, 12 and 15 a e posi i ely a ec ed by he u i-
liza ion o al e na i e ma e ials inco po a ing was e since i p olongs
he li e cycle o he la e and alle ia es land ill was e disposal,
among o he s.
These esul s indica e ha while o en al e na i e ma e ials do in ac
show p omise o educing en i onmen al impac s o he buil en i-
onmen , by how much can be a challenging ques ion o quan i y and
depends on a a ie y o ac o s. Ne e heless, he eu iliza ion and
alo iza ion o biomass ash is always going o ha e a be e en i on-
men al pe o mance han ash land illing.
Conside ing he ob ained esul s, i can be concluded ha i is
easible o inco po a e biomass-ash was e in o gypsum o non-load
bea ing applica ions in he cons uc ion sec o , such as gypsum pas e
o con inuous coa ing o p e ab ica ed gypsum boa ds.
This esea ch lea es se e al esea ch lines ha can be u he
add essed in he u u e, such as he pe o mance o he compound in
e ms o du abili y, ma ke / egula o y ba ie s o accep ance o ma e-
ials including biomass ash, LCA analysis o he iabili y o ecycling he
new was e-con aining composi es.
CRediT au ho ship con ibu ion s a emen
Flo es-Colen Inˆ
es: W i ing – e iew & edi ing, Supe ision.
Ped e˜
no-Rojas Manuel Alejand o: W i ing – e iew & edi ing, W i ing
– o iginal d a , Resou ces, Me hodology, In es iga ion, Fo mal analysis,
Da a cu a ion, Concep ualiza ion. Po as-Amo es C´
esa : W i ing – e-
iew & edi ing, W i ing – o iginal d a , Valida ion, Resou ces, Me h-
odology, In es iga ion, Fo mal analysis, Da a cu a ion,
Concep ualiza ion. Villo ia-Saez Paola: W i ing – e iew & edi ing,
W i ing – o iginal d a , Valida ion, Resou ces, Me hodology, In es i-
ga ion, Fo mal analysis, Da a cu a ion, Concep ualiza ion. Mo ales-
Conde Ma ía Jesús: W i ing – e iew & edi ing, W i ing – o iginal
d a , Valida ion, Resou ces, Me hodology, In es iga ion, Fo mal anal-
ysis, Da a cu a ion, Concep ualiza ion.
Decla a ion o Compe ing In e es
The au ho s decla e he ollowing inancial in e es s/pe sonal e-
la ionships which may be conside ed as po en ial compe ing in e es s:
Cesa Po as-Amo es epo s a el was p o ided by Go e nmen o
Spain Minis y o Uni e si ies. Paola Villo ia-Saez epo s a el was
p o ided by Go e nmen o Spain Minis y o Uni e si ies. Ma ia Jesus
Mo ales-Conde epo s a el was p o ided by Go e nmen o Spain
Minis y o Uni e si ies. I he e a e o he au ho s, hey decla e ha hey
ha e no known compe ing inancial in e es s o pe sonal ela ionships
ha could ha e appea ed o in luence he wo k epo ed in his pape .
Table 5
Cha ac e is ics o he cons uc ion sys em in he açade.
Ma e ial Bulk
Densi y
(kg/
m
3
)
The mal
conduc i i y
(W/(m⋅K))
Thickness (m)
Se ille So ia
Single-laye cemen
mo a
1900 1.300 0.015 0.015
Pe o a ed ce amic
b ick
900 0.500 0.115 0.015
Cemen mo a
plas e ing
1700 1.000 0.01 0.01
Non- en ila ed ai
chambe
1.2 0.220 0.04 0.04
Mine al wool 45 0.022 0.03 0.05
REF Double hollow
b ick
900 0.500 0.09 0.09
REF Gypsum plas e 988 0.300 0.015 0.015
WBA25 Plas e block +25%
WBA
1084 0.247 0.1 0.1
WBA25 Gypsum plas e
+25% WBA
1084 0.247 0.015 0.015
Table 6
Cha ac e is ics o he cons uc ion sys em in he la oo .
Ma e ial Bulk
Densi y
(kg/m
3
)
The mal
Conduc i i y
(W/m⋅K)
Thickness (m)
Se ille So ia
Ce amic loo ing 2400 1.900 0.01 0.01
G ipping cemen
mo a
1700 1.000 0.01 0.01
Cemen mo a 1700 1.000 0.03 0.03
Ex uded polys y ene
(XPS)
35 0.034 0.04 0.055
Wa e p oo ing.
Bi uminous shee
2100 0.700 0.01 0.01
Ligh ened slope
mo a wi h
expanded clay
700 0.220 0.12 0.12
Conc e e slab 1110 0.938 0.30 0.30
Non- en ila ed ai
chambe
1.2 0.560 0.15 0.15
REF Lamina ed gypsum
boa d
988 0.300 0.015 0.015
WBA25 Lamina ed gypsum
+25% WBA boa d
1084 0.247 0.015 0.015
Table 7
Ene gy consump ion due o he hea ans e o ai enewals and h ough he en elope o he building loca ed in Se ille and So ia.
Hea ans e ype Hea ing Cooling Hea ing +Cooling
Consump ion (kWh) Sa ings Consump ion (kWh) Sa ings Consump ion (kWh) Pe cen age
SEVILLE
REF Reno a ions 63,902 26,348 90,250
WBA25 Reno a ions 62,762 2% 25,628 3% 88,390 2%
REF En elope 16,707 6889 23,596
WBA25 En elope 15,917 5% 6500 6% 22,417 5%
SORIA
REF Reno a ions 246,380 3139 249,519
WBA25 Reno a ions 245,891 0% 2752 12% 248,643 0%
REF En elope 56,824 724 57,548
WBA25 En elope 55,194 3% 618 15% 55,812 3%
M.A. Ped e˜
no-Rojas e al.