Delft University of Technology
Stereological Methods In Cement-Based Materials Technology
A Survey Of My Research Group’s Activities During The Past Half Of A Century
Stroeven, Piet DOI 10.5566/ias.2207 Publication date 2019 Document Version Final published version Published inImage Analysis and Stereology
Citation (APA)
Stroeven, P. (2019). Stereological Methods In Cement-Based Materials Technology: A Survey Of My Research Group’s Activities During The Past Half Of A Century. Image Analysis and Stereology, 38(3), 201-211. https://doi.org/10.5566/ias.2207
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Image Anal Stereol 2019;38:201-211 doi: 105566/ias.2207
Communications
201
STEREOLOGICAL METHODS IN CEMENT-BASED MATERIALS
TECHNOLOGY
A survey of my research group’s activities during the past half of a century
P
IETS
TROEVENFaculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the Netherlands e-mail: p.stroeven@tudelft.nl
(Received June 23, 2019; revised October 27, 2019; accepted October 27, 2019)
ABSTRACT
Four topics of high engineering relevance in which we were involved are introduced herein. Aggregate packing in concrete is of obvious relevance: denser packings lead to reduced cement demands, while modern developments in the (super) high performance range of cementitious materials are based on particle packing. Fiber reinforcement efficiency in concrete that we have studied extensively offers a relatively simple stereological problem for which Cauchy laid down the fundament. In the third problem of damage analysis the dispersion of small cracks in concrete is at issue. Insight into damage characteris-tics would be relevant in all (fracture) mechanical experiments. This topic can equally be linked to Cau-chy. In both cases, the data acquisition by stereological methods is indicated. The fourth topic is of high actual relevance. It involves porosimetry in computer-simulated (virtual) cementitious materials, ultimate-ly aiming permeability estimation. The stereological problems involved are indicated, and - again – Cauchy can be linked to finding solutions. Finally, new, mostly yet unpublished developments are indi-cated aiming for more economic procedures as well as improving reliability of permeability estimates by nano-packing of globules, so that ultimately this methodology could replace the laborious and expensive (and biased) experimental route.
Keywords: Cauchy, aggregates, fibers, cracks, pores
INTRODUCTION
This paper is intended as a “farewell message” to my dear colleagues and friends in the ISS community, focusing on what I personally learned in this ISS community and showing to which engineering
problems I applied it in the concrete technology world during the past half of a century. Hence, I herewith
want to show my gratitude to the very community: it enriched my life, as a concrete technologist and as a human being!
I enjoyed my first experiences with STEREOLO-GISTS in the ISS community during the Bern conference in 1971. I was involved in an extensive study in the concrete materials field for my PhD study that I completed in 1973. For most PhD committee members out of “my” field, the 329 pages of my dissertation were probably outside their capabilities,
and the stereological approach made this an even more serious problem. Although I received my PhD degree –
yet not without some overt animosity– for my colleagues in Delft I was considered for the rest of my
active life an outsider who always knew better… As a consequence, the appointment in 1997 to professor was due to cooperation partner Beijing Jiaotong University in China, not to my home institution…
So, I figured that as a young Dr. I should convince colleagues that stereology was a powerful tool for solving practical engineering problems in the field of concrete technology. A highly relevant field was steel
fibre reinforced concrete (SFRC), which presented the simplest stereological conditions I could imagine:
dispersed lineal elements in space. This task was supposedly easier than doing so for the damage
analysis problems I had faced earlier in my PhD study.
Motivation to accept this mission was also coming from serious violations to stereological concepts I had discovered in both fields.
Looking backwards, the research efforts in the previous period involved four major engineering topics with stereological background. The two selected ‘promotion’ topics (SFRC and damage analysis) are nowadays quite established. Other contributions came from all over the world. The ‘French school’ can
ne st 19 19 in ex ef po B an is be St re re ge pa so in Y St ne in (L st in a of ca te th co re th th pr co ha re cu (a evertheless b ereological e 989; Dequied 989). The pa n the series xperimenting fforts, the ossibilities an
razil Nut Eff nd 2012). Th of recent dat e laid down troeven and S eceiving maj esearch institu enerally not articles. Cauchy c olid stereolog nvestigations Yet, additiona tructuring (D etwork topo nspired by a ty LaValle and ars is equally n life sciences consequence f porosimetry an constitute echnology re heory!
PARTIC
PACKIN
The subje oncrete in w eplaced by mo hat could easi heir shape anroduced as ontaining d ardening, a emoved by sa
ubes were ser at least) visib be mentione expertise (Car dt and Redon article packin and elabora as well a latter fac nd assessmen fect (BNE), s he permeabili te. Hence, no n yet in maj Słovik; Li and jor attention utions in the based on D concepts (Ca gical basis u
(Li and Stroe ally, the Dou DRaMuTS) sy ology should ypical stereol Kuffner, 200 y inspired by s (Gundersen e, we can safe y and permea an interestin esearchers f
CLE DISP
NG
ect matter of which the largono-size 16 m ly be distingu nd colour (F 250 mm ifferent am 25 mm dist awing. There rially section ble in two ed here bec rcassès, Olliv n, 2001; Gran ng problem is ated by exte s by compu cilitating fo nt of peculia see Stroeven ity issue in v
ot all our achi ajor publicati d Stroeven). by a numb world, altho DEM packing auchy, 1882) under the ma even*; Stroev uble Random ystem for asse
d be ment logy-related r 01). Also, pr a stereologic n, et al., 1988 ely state that ability estimat ng playgroun familiar with
PERSION
part of my gest aggrega mm ceramic uished in sect Fig. 1). The cubic conc mounts of turbed bound eupon, the res ned, so that a successive sSTROE cause of th vier and Ring nju and Ring s the oldest o ensive physi uter simulati or verificati ar effects (e. and He, 201 virtual materi ievements cou ions (Stroeve It is a field a ber of famo ough studies a g of the bind ) constituted ajor part of o ven and Słovi m Multiple Tr essment of po tioned becau robotics meth robing pores cal method us 8; Stroeven). various aspe tion of concr nd for concr h stereologic
N AND
PhD study w te fraction w (‘steatite’) ba tions because ‘realcrete’ w crete sampl steatite. Af dary layer w sulting 200 m all spheres we ections. On EVENP: Stere heir got, got, one ical ion ion .g., 11c ials uld en; also ous are der d a our ik). ree ore use hod by sed As ects rete rete cal was was alls e of was les, fter was mm ere an electr all recon The e could result (BNE (Stro 2012 Fig. 1 Fig. (top) eological meth ric tablet we r steatite gra nstruction of t effect of steat d be assessed ts was the E) in the speceven and Stro ).
1. Section of
2. Represen and from cru
hods in cemen recorded thre ain sections the steatite st tite content o d in this way detection of imens with th oeven, 1999; steatite concr ntative partic ushed rock (b nt-based mater ee points on p s. This al tructure in the on distribution y. Among the f the Brazil he largest ste Stroeven and rete.
cles from flu bottom). rials perimeters of llowed 3D e specimens. n parameters e interesting Nut Effect eatite content d He, 2011c; uvial gravel
Image Ana Fig. 3. Sim (right): nin in Fig. 2. This computer-m nearest ne compared depicted b the inaccu Stroeven e Simul aggregate mechanica 2011a and types of p respectivel proves th simulated. Fig. 4. Fre Δ3, among “realcrete” concrete), Difference serial secti al Stereol 2019 mulation strat ne regular pol topic was made “steati eighbour distr with aforem y Fig. 4. Maj uracies in sa et al., 2007; L ating in ceme of fluvial o al properties d 2011b; 2012 particles were ly, as demon hat practical equency distri g 16 mm cera ” (Fig. 1) and respectiv it i es are mainly ioning of the 9;38:201-211 tegy of arbitra lyhedra with continued ite” concrete ribution of t mentioned ex jor deviations awing! (Stro Le and Stroev entitious mat origin or of was also p 2). Ellipsoid-t e employed nstrated by Fi l mixes cou ibutions of th amic balls in d “compucret
is avoided i
y due to sawi realcrete. ary shaped ag facet number decades lat e. In doing s the grains co xperimental d s were found oeven, 1973, ven, 2012).terials the eff f crushed ro ossible (He, type or polyh for the simu igs. 2 and 3. uld be acc he nearest nei 200 mm sam te” (computer
in this surv
ing inaccurac 203 ggregate; (lef r 4~8 were se ter on so, the ould be data as d due to 2015; fects of ock on et al, hedron-ulation, Fig. 5 curately ighbor, mple of r-madeey ely.
cies for F o G g fr (2 in (e p p M p a d ft): differently electively em Fig. 5. S-V cu of composite p Guo (1988) w get an even b from an exp 2006). Of course nto the (supe exceeding th particle pack physical (van More material packing of par already proo discussed subj 0 500 1000 1500 2000 0 S u rf ac e a rea ( m m 2) y shaped ellip ployed to rep urves of crush polyhedra and were employe better corresp erimental ap e, major upg er) high perf hat of regular king phenom der Waals) l developmen rticles. Howe f the releva ject. 1000 Vo Sphere GR in Reference LS in reference Composite polyh Revised compos psoids repres present river ghed rock type nd of the sphe ed as well as pondence with pproach by grading of m rformance ran r steel qualit mena! Purpos forces in an nts also rely a ever, this sing ance and a 2000 olume (mm3) e hedra by Guo site polyhedra
sent river grav gravel aggreg
es (GR and L ere. Field data s revised data h reference d Erdogan, et material quali nge of concr ies) is based se is to exp n optimum w at least partly gle example m actuality of 3000 40 vel; gate LS), a by a to data al. ities rete d on ploit way. y on may the 000
co ca (2 fo co of im pr un 2 an m di ra m em th Fi sp lin ex pr by re th se th an P
STEEL
CONC
Buffon for oncrete techn alled “needle 2006). It co ollowing exp oncrete can bHerein f a line grid mage, such a rojected lengt nit of area of centuries la nalysis metho Our first method involv ifferent fiber atios by weig moduli of the mployed, max he fineness ig. 6. (bottom pecimen of 70 ne grids. The stee xperiments as rovided with y counting f elated to the C he counting p econd perpen he specimen. nisometry, ba 2 ' L A P L
LP
L FIBRE
CRETE
rmulated in nology. The o e problem” is ould readily pression by w e analyzed is the avera and (steel) fi as in Fig. 6 th perpendicu f the image. S ater his dire odology that it application ved the ana r types in SF ght (w/c=0.4 e aggregate ximum grain modulus (FM m) X-ray radio 0x200x1000 m el fiber rei s well as the additional fib fibers in or Cauchy conce planes is paral ndicular to it a It was found ased on the so L
REINFO
1770 a probl original state s given in St be transfor which fiber age number fiber projectio 6. Further, L ular to the gr Saltikov prop cted (and ra is making use n of the B alysis of the FRC. Two w and 0.6) an (f=3.27 and n size being 8 M) is an em ograph of a “ mm (top). Co inforced 3-e splitting t3-en ber dispersion rthogonal se epts (Cauchy llel to the fra and parallel t d, as an exam o called Stroe STROERCED
em relevant ement of the troeven and H rmed into t distributions ( of intersectio ons in an X-r L’A is the to rid direction p posed more th andom) seca e of eq. (1). Buffon/Saltik e dispersion water to ceme nd two finene f=3.89), we 8 mm. Note th mpirical figu “vertical slice ompaction by point bendi nsile tests w n characterist ctions. This y, 1882). One acture plane, t to the bottom mple, that fib even concept EVENP: Stere for so Hu the in (1) ons ray otal per han ants kov of ment ess ere hat ure obtain of an sieve speci contr remo a set result top). 6, bo apply (Stro Stroe 1986 Amon reinfo it re behav T bendi streng speci distri (Stro Stroe 1986 e” (totaling 10 y gravitation w ing ere tics is e of the m of ber (in this c fibers tensil (Fig. See, other reinfo N in sp eological meth ned by addin n aggregate re es, and divid imens, measu rolled tested ved from the t of about ted from eacVisualization ottom) of p ying orthogon even, 1979c even and Da ; Stroeven a ng other thin orcement effi ndered poss vior of the SF The remainin ing experime gth tests in ei ific informati ibution param even, 1979c even and Da ). 0 in this case) was in vertica case a mixtur s), was direct le strength at 7) (Stroeven e.g., Stroeve r relevant c orcement in c Note further t pace and in hods in cemen ng the total p etained on eac
ing the sum uring 70x200 d to beyon testing mach equally size ch full-size s n was by way pre-loaded c nal grids. For ; 2009; Stro alhuisen, and nd Słovik; S ngs, it provi iciency of the ible to inte FRC specimen ng prisms we ents and the c ither one of o ion on crack meters of the ; 2009; Stro alhuisen, 199 ) of a test-loa al direction. A re of 2D and tly reflected b t increasing v n and Babut, n (2009) for ontributions concrete. that in SFRC n the forthco nt-based mater ercentages of ch of a specif m by 100. A 0x1000 mm, nd ultimate, hine and secti ed prismatic specimen (F y of X-raying concrete spe r detailed info oeven and S d Stroeven 1 Stroeven and ided informa e different fib erpret pheno ens in structur ere subjected cubes to spli orthogonal dir k developmen full-size spe oeven and S 96; Stroeven
aded (and cra Analysis is by 3D “random by anisotropy volume fracti , 1986; Stroe a large selec to the fie C we deal with oming dama rials f the sample fied series of total of 48 were thereupon ioned so that c specimens ig. 6 at the g slices (Fig. cimens and ormation see Shah, 1978; 996; Babut, d Hu, 2007). ation on the ber types and menological ral terms. d to 3-point itting tensile rections. For nt and fiber ecimens, see Shah, 1978; and Babut, acked) SFRC y orthogonal mly” oriented y in splitting ion of fibers even, 1993). ction of also ld of fiber h line length age analysis
Image Anal Stereol 2019;38:201-211
205 approach with surface area in space. Cauchy provided the relationships that are at the basis of counting observations and determination of total line length (SFRC) and total surface area (Damage analysis), respectively (Cauchy, 1882).
Fig. 7. Anisometry in steel fiber dispersion (top) and anisotropy of splitting tensile strength fs in N/mm2 of steel fiber reinforced cubes at increasing fiber volume fraction Vf (bottom).
For the fibre case of Fig. 6, upon application of the Stroeven concept of a mixture of 2D and 3D fibre portions, the following equation is obtained (Stroeven, 1979c; 2009) ' 1 2 1 2 2 V V L
L
(2)
where is the total length ratio of the 2D fibre portion over that of the total amount of fibres. Mono-size fibers are assumed in this case, however, also for multi-size and curved fibers, similar models have been expanded. In eq. (2), LV is the total fiber length per unit
of volume and LV’ the component in the plane of the
2D portion; so, in the case of Fig. 6 oriented perpendicular to the compaction direction of the prismatic specimen. Consequently, it is the effective part of the fiber reinforcement because loading direction will be perpendicular to the plane of the X-ray image.
DAMAGE ANALYSIS
Buffon/Saltikov provided also the basis for quantitative analysis of cracks in concrete. By as well adopting the Stroeven concept for spatial crack development (combining at maximum, 1D, 2D and 3D portions), the orthogonal measurements of intersections of line grids with the cracks can be interpreted in spatial terms. Fig. 8 concerns the case of direct compression, requiring only a 3D and 1D portion, the latter having its axis of orientation coinciding with that of the loading. Hence, the solution for the spatial interpretation of cracking can be based on a section parallel to the loading direction in which the orthogonal observations
P
LPandP
Lsuffice (Fig. 8, at the left).In mathematical terms, it is found that the crack surface area per unit of volume, SV, is related to
orthogonal measurements in the mid-section of the compressed specimen by 4 1 2 V L L S
P P
P
(3)
In tension testing, a combination of 3D and 2D portions is required. Again, an axial section can be sampled by an orthogonal line grid. For methodological details and results of applications, see (Stroeven, 1973; 1979b; Stroeven and Słovik; Stroeven and He, 2011a; 2011b). Of course, any (fracture) mechanical investigation on cementitious materials can profit from the structural research efforts discussed herein, since it will promote the understanding of the recorded phenomenological behavior.
Note that these labour-intensive contributions to the aforementioned topics had to be terminated at the end of last century, because physical experimenting became too expensive. Therefore, I figured we should instead use modern computer facilities. So, the last subject is hot, actual and highly relevant. My PhD student and son, Martijn, developed the first
professional Discrete Element Method (DEM) - SPACE
- in our group that became operational around the millennium break (Stroeven, M., 1999). During the next years, a series of my PhD students have used it (and an upgraded version, HADES) in studies on virtual
cementitious materials (compucrete). Particle packing
problems (as discussed earlier) and particularly
permeability estimation were the issues of interest and
engineering relevance.
0 4 8 12 16 0 4 8 12 16 NA observed NA designed 0 2 4 6 8 10 0 1 2 3 4 fS VfIm
Fi sm a fo el st lo sh ge m st fie 2D fib th m St m (D m te di si K pa re
mage Anal Ste
ig. 8 (right) P mall cracks v complete, ce or intersection In Stroev laborated on ereological r og”, hence, it howing up of eometric aver more closely arting to em elds!
POROS
Applicatio D problems i bre reinforce hey found th models for pe troeven, et a materials are DEM) – desp methods are echnology, l ispersion cha mulation by Kinetics Mod articles yield esult of the v ereol 2019;38: Part of the se isible under U entrally locate n counting. ven and Sł n the Cauch readers this i t is avoided f the Cauchy raging operat reflects my mploy his coSITY AND
ons of the C is not limited ement or crac heir way in ermeability al., 2015). Fo produced by pite Random more freq leading how aracteristics. XIPKM (eX del) that is b ding also sph vector-based :201-211 ction image o UV light upo ed axial secti łowik we h hy concepts. is “as easy a in this surve y constants oftions was dem
Aha Erlebn oncepts in o
D PERM
auchy conce d to the struct ck structures. porosimetry (Li and Stro or that purpo y Discrete ESequential A quently used wever to b The next ste Xtended Inte based on sp herical hydrat approach), ap of a pre-loade on application
ion (note agg
have explici However, as falling off ey. Instead, t f 1/2 and 2/π monstrated. T is when I w our engineeri
EABILITY
pts for 3D a tural analysis . More recen and predicti oeven 2017a ose, our virtulement Meth Addition (RS d in concr biased parti ep is hydrati egrated Parti pherical ceme
ted grains (as part from int
ed compresse n of a fluores gregate grain itly for ff a the π in This was ing
Y
and s of ntly tive a,b; ual hod SA) rete icle ion icle ent s a ter-partic Navi Fig. 9 ed prismatic cent spray. (l sections). Or cle interferen and Scrivene 9. Simulated concrete spec left) Manually rthogonal line nces (Navi an er, 2005) (Fig hydrated blen cimen reveal ly copied crac e grids are su nd Pignat, 1 g. 9). nded cements myriads of ck pattern of uperimposed 996; Pignat, paste
Image Ana Fig. 10. (t paste with 300 m2/kg complex p system afte M., 1999). Pore t by DRaM Structuring developme and pore s (SVM), ins also the In These ly” dispers trees from input data yielding in 2017; Stro complexity 10. al Stereol 2019
top) All pore h w/c = 0.4 . Porosity is pore structur er removal of topology of th MuTS (Dou g), see Fig. ents in roboti ize is determ spired by a m ntroduction). investigation sed points in m DRaMuTS a for a clas nformation on oeven et al. y of the pore 9;38:201-211 es in 90 day 4 and Blain s 19%. (bott re in the vec f the hydrate he capillary n uble Random 10, an app cs (as stated mined by Star methods used ns are based n 100 μm cu and the pore ssical networ n permeabilit , 2015; Li e structure is ys hydrated c ne surface a tom) Tortuou ctor-based hy structure (Str network is as m Multiple proach inspir in the Introdu Volume Mea in life scienc on 2x105 “ra ubes. The sm e sizes by SV rk analysis, ty (Stroeven a et al., 2017 s visualized 207 cement area of us and ydrated roeven, ssessed Tree red by uction) asuring ces (see andom-moothed VM are finally and Li, 7). The in Fig. ap th p s fi th d a a c e to li e a s q fi o w p re th d S p re 2 s re h th h sp p n F th d h g (a New dev approach. Ins he network an pore sections tars in about find the pore
he same poin distribution fu are intimately areas in the constant ½ economization ortuosity inf inear tortuos expressed by 𝑅 1 Herein p and projected imulated data quite well pre first part of it of the pore sy we additional pore channel eduction fact he non-spher determined b Significant red paper is in pre
FUTUR
The last esearch in the 2017), as afor tudy of K. L esulted in hydration layhat causes the have replaced
pherical sur packed nano-g nodules is est From the surf hey start clus declining glob The trad hydration sim grains that ex accounting fo elopments fo stead of asses nalysis, a sim are used. T 200 pore sec throat (=sma nt) (Stroeven unctions of t y related. Sp two distribu (Stroeven n effort is to formation. In ity index of 1 𝑝 is porosity a d pore length a based on the edicted by po t. For estima ystem by this ly require in ls and their tor expressin rically shaped by FET (Le ductions in ef eparation).
RE RESE
two decades e field of con rementioned. i (Li and Stronano-level er of cement e expansion o d this outer hy face of hyd globules. In t timated as 5 face of the so stering in frac bal density ov ditional XIP mulation is b pand due to or interferenc ocus on the ssing 2x 105 milar number This avoids p ctions at eac allest among n). It is foun throats and r pecifically, th utions differ and Słovik o predict pe n Stroeven f pores, Rl, i and l and l’ h on a straig e second half orosity data a ating transpor s so called h nformation on r median 2D ng the actual d pore sectio e, 2015; Li fforts are exp
EARCH
s we have b ncrete permea . As a follow oeven, 2019) explorations t particles. T of the hydrati hydration laye drated ceme the literature, nm (Jenning o called inner ctal-like “arm ver the outer l PKM vector based on sp hydration in ces). This is economy of throat sizes of IUR orien probing by 2 h nodal poin pore sections nd that the s random secti he median p by the Cau k). A seco rmeability fr and Słovik s approximatare pore len ght line. So f of Eq. (4) se according to rt characteris hybrid approa n the number D size, plus conductance
ons. The latte et al., 201
pected (a jour
been conduct ability (Li, et w up of the P , this has fina in the ou This is the la ing particles. er of the smo nt particles the size of s gs, 2000; 200 r hydration la ms”, leading t layer (Fig. 11 r approach pherical cem a spherical w shown in a 2 the for nted 2-D nt to s in size ions pore uchy ond rom the tely (4) ngth far, eem the stics ach, r of s a e of er is 17). rnal ting al., PhD ally uter ayer We ooth by uch 08). ayer to a 1). to ment way 2-D
lo ob po re se ce to ap pa da St ex un sp sp tim re as of to st Fi co un ho gr in ow-density se bviously redu ore surface is educe the c ection. When ement to conc o dilution an pproach in arameters can ata on concre troeven). He xpensive test ncertainties a pecimens), th pecimens, wo me and mone eliability! Problems ssessing size f the quasi-fr opic of stereo tudy! ig. 11. The si onsisting of D nder two omogenous e rowth among n outer layer i et up in Fig. 1 uces pore size s roughened in onductance n transferring crete, we dea nd tortuosity combinatio n bring the ete permeabil ence, instea ting (with a as to the degr he sketched ould not onl ey savings bu arise in t and shape ch fractal “arms” ological natu implified stru DEM-packed different gr expansion by g mono-size g is similar in th 11 (top). The e (and chang n Fig. 11 (bo of water th g the informa al with additio y. It seems on with t simulated an ity on close d ad of labori accepted sho ree of water s strategy, ba ly compete f ut would be a the nano-ap hanges in 3D ” in Fig. 11. ure suitable f ucture of cem d mono-size c rowth mech y XIPKM; (b globules. Am he two cases. STROE e nano-approa es shape) wh ttom). This w hrough a po ation of virtu onal effects d that the nan these mater nd experimen distance (Li a ious and th ortcomings a saturation of t ased on virtu favorably as at least of equ pproach as D during grow An interesti for a next Ph ment paste in 2 cylindrical dis hanisms: (to bottom) fibro mount of C-S . EVENP: Stere ach hile will ore ual due no-rial ntal and hus and the tual to ual to wth ing PhD 2D sks op) ous S-H
C
H plung exper on th analy foreig many confe field with and r last P Wuha PhD in co to the deter both proje S SFRC leadin Li, e publi statu ment of h globu stuff prime perm conce Stroe I stereo kept shoul to the proba conce techn rural partic in the and suppo althou case cuts. partly eological methCONCLU
Hence, my ged with fulrimenting in he very labo ysis problem gn counter-p y years in erence procee (of the ma the ambition reliable tool f PhD student o an Universit in 2001 (Shu oncrete is inti e fiber topic mining the l in 3D sp ections). Studies on al C - have re ng journals s et al., 2015 ications, amo nascendi. Br ioned, such a hardened cem ules dispersed for stereolo e attention meability estim ept, as mentio even and Słov
It should fin ology-related me busy all ld be mention e impression ably rose from erned with nology “avan project in S cipation, whi e framework particularly orted by th ugh political (as the last a Major objec y replacing P hods in cemen
SIONS
“stereologica ll ambition the framewor orious particl ms in concret parts on SFR a couple edings and i ny thousand n to show ste for solving en on this topic y of Techno ui, 2001). Of imately relate (due to the ength of a li ace, by av ll topics - as esulted in se uch as in IAS ; Hu and ong others w rand new dev as simulating ment paste c d in fractal-li gists! Yet, r to econo mation using oned in this p vik). ally be stres d topics were those years. ned here, bec n of “hard” te m the discuss sustainabilit t la letter”. A Sri Lanka wi le laboratory of cooperatio with Viet e Dutch Go changes in th accepted proje tive was to r Portland cem nt-based mater al life” start into extensi ork of my PhD le packing ate) and ther
RC. It resulte of hundred in journals in ds available ereology a ve ngineering pr was Shui Zh ology who r f course, dam ed in stereolo two Cauchy ine or area o veraging of s already me eries of pub S (Stroeven, Stroeven, 20 with Kai Li, velopments ca the outer hyd consisting o ike “arms” (F recently, we omic develo – again – Ca paper (see als
ssed that the e not the onl At least, one cause it may o echnology ac sed topics. T ty aspects Application fo ith Architect y research wa on with Tanz tnam. The overnment ( he country re ect) in signif reduce CO2 e ment by fine-rials ted when I ive physical D study (i.e. and damage reupon with ed over the papers in n the SFRC worldwide), ery practical roblems. My honghe from received his mage analysis ogical terms concepts of of a surface, their total entioned for blications in et al., 2012; 006). Some are still in an hereby be dration layer of nano-size Fig. 11); real have given opments in auchy’s 3-D so: Stroeven; e mentioned ly ones that e other topic offer nuance ctivities that This one was in concrete ocussed on a tural student as conducted zania, Brazil latter was (1982-2002), sulted in our ficant budget emissions by grained rice
Image Anal Stereol 2019;38:201-211
209 husk ash (Bui, 2001) or non-commercial metakaolin (Vu, 2002). Mind that this was significantly before such CO2 emissions were internationally declared leading to global warming, hence it was hard in our case to find moral and, particularly, financial support. Note that the given examples are particle
packing-driven. This illustrates again the actual relevance of the
first topic discussed herein!
At the final end of this paper it should be men-tioned that promotion of stereology in my field was also
explicitly in my mind during the many years that I participated in the ISS community as “regional representative” and as Editorial Board member for Acta Stereologica and Image Analysis and Stereology.
REFERENCES
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