Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
EFFECT OF SELF HEALING PROMOTED
MATERIALS BLENDED WITH CARBOXYLIC ACID ON
PERMEABILITY
You Youkun a,b,c , Qian Chunxiang a, Miao Changwen b, Ye Guang c, K. van Breugel c
a
b
c
Southeast University, Nanjing 210018, China
Jiangsu Provincial Building Institute , Nanjing 210008, China
Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1,
2628 CN Delft, The Netherlands
A kind of calcite crystalline proliferation cementitious mixture consisting carboxylic acid and carbonate salts
used as self healing promoted materials (SHPM) was presented. Study was focused upon formulating the
leaching and deposition equilibrium process of calcite crystals proliferated by SHPM during direct hydraulic
permeability test. Results of permeability experiments and Environmental Scanning Electron Microscopy
(ESEM) observation confirmed the properties of self healing of the materials. Comparing to blank paste sample,
the permeability of paste coated with SHPM reduced significant with the elapse of time, while the permeability
of paste blended with magnesium salt and cured in dilute carboxylic acidic solution dramatically increased
during the leaching period. Compared to maleic acid and malic acid, tartaric acid mixed in SHPM had a high
efficiency to modify the crystalline morphologies of deposited calcite and aragonite. Study is aimed to give a
comprehension of self healing process of concrete in ambient weak acidic saturated environment.
Keywords: Self-healing, Carboxylic Acid, Calcite, Carbonate, Crystals, Precipitation,
Permeability
1
Introduction
Durability of concrete structures exposed to different environments has become a
predominant concern in the concrete industry. The durability depends both on the ability of
concrete to resist the penetration of aggressive substances from the environment, and on its
self healing ability. Degradation products might be produced and deposited in cementitious
materials in an aggressive environment. However, some of these reactions might play a role
of self healing properties on the contrary.
As some researcher pointed out, self healing is largely attributed to the dissolution and
redeposition of hydrates or crystals in cracks or macroporos[1,2]. According to Natalya Hearn
[3], Dissolution, deposition and crystallization is the main mechanism of self-healing in
mature concretes, while carbonation has a low degree of influence on the performance.
However, Carola Edvardsen[4] denoted that calcium carbonate crystals deposited in cracks
might be almost the sole cause for the self healing. The mechanism of self healing during the
carbonation might be assumed as follows: Concrete carbonation process involves the
chemical reaction of portlandite, and calcium silicate hydrate, C-S-H, in the cement matrix
with carbon dioxide gas leading to calcite, CaCO3 and other metal hydroxides give
carbonates.
1
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
The calcite mineral is 17% larger than the portlandite mineral, hence it may reduce the
permeability and porosity especially in poor quality concrete [5]. Practically, concrete seldom
suffer from single aggressive chemical substance attack in a natural environment. Some
species immigrated from outer environmental might also play a self healing promote role in
some occasions. Recent report manifests that [6-8] concrete aged in the mild acidic
environment did not result in any detrimental effect and in some cases even a positive
influence was observed.
Some natural organic acids (e.g. humic and fulvic acids),which have chelating or
complexing function with divalent cations or multivalent metal cations in cementitious
alkaline pore solution. With the aid of chelating carboxylic acid, divalent or multivalent
cations are more transportable in the global porous system and feasible to precipitate in
macroporoes or cracks. The self healing process might be proceeding continuously in the
materials. On the other hand, if the cementitous materials is immerged in flow water
circumstance,the higher migration rate of metal cations ,the more leaching of the cations from
the materials. In this case, the carboxylic acid would play an corrosive degradation role on the
materials. Leaching of alkaline would increase permeability while crystalline deposition
produced during the reaction between carbonation anion and divalent metal cations in pore
solution might reduce the permeability of cementitious materials. During the equilibrium
process, carboxylic acids might also play contradiction roles. Firstly, as effective crystal
growth inhibitors, carboxylic acids improve the permeable alkaline leaching; secondly, once
the carboxylic group released from the chelated divalent alkaline cations in solution, the
alkaline reaction crystals re-deposition would be transferred in the microcracks or
marcroporos elsewhere. Thus, carboxylic acid might have a positive contribution to self
healing efforts. However, investigation on the mechanism of self healing incorporate the
synergetic effect of multiple corrosive chemicals has not yet attached more attention.
In this article, different SHPM are experimental compared in direct hydraulic permeability
test. Three carboxylic acids, i.e. maleic acid (ME),malic acid (MA) and tartaric acid(TA),
were compared in fabricated self healing promoted materials. The material was coated on the
paste to investigate paste permeability during a long time elapse of test.
2
Materials and methods
2.1
Materials and preparing
The composition of the cement paste tested is w/c =1/2. The cement used is of type CEM-I
32.5R according to European Norms (EN 197-1). Its chemical composition is given in Table
1.
Table 1: the chemical properties of CEM I 32.5R (%)
CaO
SiO2 Al2O3 Fe2O3
MgO K2O
63.4
21.0
5.03
2.83
2.0
0.65
Na2O
0.24
SO3
3.0
C3S
63.0
C2S
13.0
C3A
8.0
C4AF
9.0
The mineral composition of CEM I 32.5R is calculated with modified Bogue equation[9] .
The Blain value of the cement is 283m2/g and 3150 kg/m3 of its density.
A high porosity concrete sample coated with SHPM (Mixed with TA) was also laboratory
prepared for observation of crystalline morphologies and measurement of porosity transfer.
The ratio of cement to water of W/C=0.75, and the ratio of sand to cement is sp=40%.The
maximum of aggregate size is 20mm.The curing regime is same as paste and the
measurement is at 56 days ageing.
2
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
The SHPM are consisted of the following components: one of three alternative carboxylic
organic acids, carbonate salt and calcium or magnesium salt. All these materials were mixed
with CEM I 32.5 R cement in a constant weight ratio of 30%, and the Portland cement is used
as inorganic binder for coating cementitious materials. The chosen carboxylic acids have
different number of hydroxyl groups in a same two carboxylic group in a molecular. The
molecular structures of three carboxylic acids are shown in Fig.1.
O
O
OH
HO
HO
O
maleic acid
OH
OH
OH
O
O
OH
HO
O
malic acid
OH
tartaric acid
Figure 1: three carboxylic acids molecular structures
The paste samples used for permeability test parallel coated with a layer grout of above
mentioned self healing promote mixture, which consisted of a kind of carboxylic organic acid,
lithium carbonate and cement .The coated grout is mixed with water in a ratio of W/B=0.3(B:
binder solider mixture material ). The amount of self healing promote material coating on one
side of paste was a constant of 1.5kg/m2 for test paste samples.
In the procedure of the sample preparation for permeability, in order to prevent bleeding, the
samples were cast into 1000 ml plastic pipe with the internal diameter of 95mm and rotated at
a speed of 5 rpm in a room with temperature of 20°C. After 24 hours rotation, the samples
were still kept in the plastic bottle and stored in the curing room with temperature of 20°C for
28 days. After 28days ageing paste disk samples were sawn from the paste column with a
thickness of 10 mm. The accurate thickness was measured to calculate the permeability.
The paste samples coated with SHPM were cured in a water filled box, keeping the base paste
immerged in water while the level of curing water is lower than the coating SHPM for an
assign curing age, e. g 7days and 28days respectively. The complex curing regime is set up
so that deposition crystals yielded by SHPM could penetrate into the inner of paste with water
suction function and reduce the paste permeability with physical clogging efforts. The main
penetrable crystals are assumed as calcium carbonate or magnesium carbonate, in a crystalline
formation of calcite or aragonite. The crystalline penetration process combines the two self
healing mechanism of carbonation and re-deposition of crystals. In addition, carboxylic acid
was mixed in SHPM to improve the characteristics of crystalline penetration. The self healing
quality is characterized by the permeability of paste samples coated by SHPM. Before the
permeability experiment, the coat of SHPM was removed to avoid its effect on paste
permeability.
In this paper, the effort of deposited crystalline calcite yielded by SHPM on porous
microstructure and permeability characteristics is contrast manifested by acceleration leaching
of magnesium salts from the paste samples. According to T. Van Gerven [10] diffusion test
results, concrete carbonation process decreases leaching of Na, K, Ca while increases leaching
of magnesium in concrete. The different leaching rate of magnesium and calcium cations
should have an effect on the permeability performance during the artificial self healing
promoted carbonation deposition process.
3
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
Paste samples blended with 5% weight of cement magnesium salt were prepared with same
cement to water ratio of 0.5 and same curing regime. Contrasting, these samples without
SHPM coating, cured in three carboxylic acid dilute solution(1gl-1) for 28days.The contrasted
permeability experimental results might show the significant difference between self healing
efforts and pure leaching efforts. The experiments were set up to reveal the self healing
mechanism.
Additionally, three different morphologies of precipitated calcite crystals were respectively
obtained by mixing two solution, one is calcium chloride (500 mmol l−1), and another is
lithium carbonate (500 mmoll−1) solution, in which dissolute a certain above mentioned
carboxylic acid with a concentration of 5mmol. l−1. The calcite crystals were simulated
precipitated after the two solution mixed and then filtered off, washed using distilled water
and dried at 105 oC. The analytical grade chemicals were used (ACS Reagent, Sigma) for the
calcite crystals precipitate experiments.
2.2
Methods
A direct hydraulic water permeability test system was adopted for permeability measurement
[11]. The thicknesses of paste samples were accurately measured with gauges of
HEIDENHAIN MT25. After saturation and lateral proofing, each sample was placed in a
device in which the water flows under a controlled pressure gradient of 0.4~0.6MPa and
temperature of 25oC. The permeability coefficient was calculated with the Darcy’s law.
3
Results and analysis
With different complexing ability and release ability, the carboxylic acid in SHPM has not
only an influence on the deposition crystal migration rate but also deposition crystalline
morphologies in porous cementitious material, which determine the self healing
characteristics of SHPM. To reveal the complicated crystalline penetration and deposition
process and their physical clogging effects on cementitious materials, direct hydraulic
permeability system set-up is used to measure the permeation quality of maturated paste
samples coated with SHPM.
Figure 2: the Cumulative flow against time for paste samples
4
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
The cumulative flow evolutions as functions of time are shown in Fig.2. For all samples, a
dozen hours are necessary for reaching steady state when permeability is calculated by the
application of the Darcy’s law. In Fig.2, the upper three curves represent the permeability
characteristics of paste samples blended with 5% weight percent of cement with magnesium
salt. These samples were cured in three dilute carboxylic acidic solutions (1gl-1) for
28days.Without carbonation salt deposition supplied by SHPM, the samples procedure a
running water leaching process during the direct hydraulic test.
In the figure, a distinguish difference permeability characteristics between self healing efforts
and leaching efforts were shown.
initial stage
lateral stage
3.0
2.0
-12
Permeability(*10 m/s)
2.5
1.5
1.0
0.5
0.0
blank
ME
MA
TA
Paste Samples
Figure.3: the permeability of initial and later stage of paste samples coated with SHPM
The calculated permeability of paste samples coated with SHPM are shown in Fig.3.The
initial stage permeability of paste without SHPM coating is 2.81×10-12m/s, with the evolution
of permeation time, it decreases to 1.99 ×10-12m/s.Comparing to the blank paste sample, all
the paste samples coated with SHPM show a lower permeability and a higher decrease of later
permeability to initial ones. The initial permeability of paste coated with SHPM(ME) is
2.78×10-12m/s, SHPM(MA)1.71×10-12m/s, SHPM(TA)with an initial negligible permeability
value. During the later permeation stage about 150 hours, the permeability of past coated with
SHPM (ME) and SHPM (MA) reduced to 1.15×10-13m/s and 1.05×10-13m/s respectively,
while the sample coated with SHPM(TA) show a small cumulative flow during the later
permeation stage, with a calculated permeability of 0.93 ×10-12m/s according to its permeation
period.
Comparing to the blank paste, the permeability of pastes coated with SHPM is efficiently
reduced. Among the three carboxylic acids, tartaric acid has a lowest permeability during the
initial permeation stage and a lest cumulative flow amount during the total permeation test.
The paste permeation measurement results might be assumed be correlate to the penetrable
ability and the degree of deposition of proliferated crystalline calcite and its modified
crystalline morphologies.
Past samples coated with SHPM show a relative lower water flow rate and cumulative amount
than the parallel blank paste samples without SHPM coating. Three carboxylic acids also
show the similar tendency of permeability, water flow rate and cumulative flow amount. The
paste samples coated with SHPM mixed with tartaric acid have a lowest permeability.
5
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
The result might be interpreted the near round calcite crystals having a high penetration
ability and deposited in most macroporos and mesoporos in a deeper depth under the coating
surface. Once all pores under critical porous radius are physical clogged, the paste might
show water impermeable under the experimental hydraulic pressure. Both of samples coated
with SHPM mixed with maleic acid or malic acid show a lower cumulative flow rate than
blank paste sample without SHPM coating. The self healing effort was manifested as
assumption of proliferated penetrable calcite crystalline deposition mechanism.
The effort of self healing provide by SHPM is aggravated by combined the carbonation and
penetrable proliferated crystalline deposition processes to density the cementitious materials.
Penetrable crystalline deposition proliferated by the coated SHPM is supposed to be the main
cause of self healing and main factors effect on permeability characteristics of paste. Three
organic carboxylic acids in SHPM introduced to the crystallization processes of CaCO3
modify the shapes of crystals, retard nucleation and growth rate, and control polymorphism
[12, 13]. The penetrable crystal morphology and its penetration rate are both significant
characteristics s of self healing efficiency and physical clogging efforts in porous material. In
the study, ESEM is used to observe the crystalline size and morphologies. The three calcite
crystals precipitated in saturated calcite carbonate salt solutions mixed with ME; MA and TA
are shown in Fig.4:
(a)
(b)
(c)
Figure 4: ESEM microphotographs of the calcite particles precipitated in three carboxylic acid solution:
(a)ME, (b) MA, (c) TA
The original calcite, CaCO3, has a trigonal crystal structure, a space group R-3c, a punctual
group of symmetry -32/m and a=b=4.990 Å, c=17.061Å, α=β=90o and γ=120o [14].From the
ESEM microphotographs of the calcite particles precipitated in three carboxylic acid solution
shown in Fig.4, the tartaric acid has the highest efficient to modify calcite morphology from
single distributed trigonal crystal to almost round of binary combined particles. However, the
maleic acid, with no hydroxyl group in the molecular, the deposited calcite morphology is
most near to the original calcite crystal trigonl morphology. It demonstrates that the number
of hydroxyl in carboxylic acid has a strong influence on the deposition crystals morphologies
in cementitious pore solution and fine cracks. It could also be hypothesized that the tartaric
acid has a highest complexing interaction with the calcite crystals among the three acids.
6
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
lateral stage
-12
Permeability(*10 m/s)
10
8
6
4
2
0
blank
ME-Mg
MA-Mg
TA-Mg
Paste Samples
Figure 5: the permeability of initial and later stage of paste samples blended with magnesium salt
The calculated permeability of paste samples blended with magnesium salts are shown in
Fig.5.Comparing to the blank paste sample, the test samples all have a higher initial
permeability and higher later stage permeability. The curing dilute acidic solution also has an
effect on the permeability of paste samples. The permeability of samples cured in tartaric acid
dilute solution has a highest value of initial and later stage permeability; while samples cured
in maleic acid dilute solution has a smallest value of permeability among the three acidic
solutions. Considering there is no calcite provided by SHPM, the permeation test results in a
leaching process of alkaline ions from the paste. The quantification of alkaline crystalline
deposition in the leached solution revealed that the sample cured in tartaric acidic dilute
solution has a highest value, which means it had high chelating interaction with the
cementitious materials.
Literatures have demonstrated that the dissolution of calcium hydroxide and a progressive
decalcification of C-S-H in a running water leaching system are the essential processes
governing degradation of cementitious materials [15]. For a paste blended with magnesium
salt and cured in dilute acidic solution, this deterioration might be aggravated in the leaching
process. With high migration rate of magnesium cations and solubility of magnesium salts,
the paste samples show high permeability. The acid sorts also has an effect on the migration
of magnesium ions and its crystalline morphologies. To investigate the this difference, ESEM
is parallel used to observe the crystalline morphologies of MgCO3 deposited in three acid
solutions as shown in Fig.6.
(a)
(b)
(c)
Figure 6: ESEM microphotographs of the MgCO3(aragonite) particles precipitated in three carboxylic acid
solution: (a)ME-Mg, (b) MA-Mg, (c) TA-Mg
7
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
From Fig.6, aragonite has a smaller particle size comparing to calcite crystals which shown in
Fig.4.The three carboxylic acids show a similar modify effort on crystalline morphologies.
The modification ability of tartaric acid is still the most efficiency one among three acids.
Nevertheless, the binary phenomenon in calcite disappeared in aragonite crystals. They are
single distributed separately.
The different permeability characteristics between pastes coated with SHPM and paste
samples blended with magnesium salts might be attributed to the following factors: Firstly,
the two kinds of carbonate crystals have different particle size. The smaller crystals have a
lower efficiency of physical clogging efforts. Secondly, according to literature data [16], the
aragonite crystals( lgK sp,aragonite=-8.36) have a bigger dissolution than calcite( lgK sp,calcite=8.475).During the Saturated permeability test, water continuously flow through the paste
samples, there is an equilibrium between dissolve and deposition process. The aragonite
crystal with high dissolution would induce a large amount of solute aragonite leached from
the outlet of permeability experimental setup. So it has a higher permeability during the initial
permeation stage. During the aragonite leaching process, the decalcification process might be
accompanied. The permeability of paste sample would remain a stable high value for its high
porosity formed by dissolve of alkaline ions. On this occasion, self healing function is no long
exist in an “opening” running water leaching environment.
From above discussion, the self healing process is supposed to have relation to cementitious
component, environment chemical substance sorts and the system characteristics of “open” or
“closed”, which determinate the dissolution and deposition equilibrium. In view of self
healing promoted mechanism, some artificial SHPM might be applied as cementitious surface
densify materials, where required a detail investigation on situ cementitious component and
environmental condition etc. In practical, the self healing effort of SHPM coated on the
maturated poor quality concrete surface might be significant due to coarse pores, fine
shrinkage cracks and interfacial transition zone (ITZ) between aggregate and cement hydrates.
These defects of microstructure provide enough capacity for crystalline deposition and high
connective of microstructure for chelating agent and divalent cations penetration: there are
two essentials process for the self healing performance.
4
Conclusions
A kind of Self healing promoted materials (SHPM) consisting carboxylic acid and carbonate
salt is proposed in this article. The permeability characteristics of SHPM are investigated and
the morphologies of chelated crystalline deposition are detailed compared.
With the aid of chelating interaction between carboxylic acid and divalent cations,
proliferated crystalline deposition, e.g. calcite or aragonite, penetrate into the internal of
cementitious porous materials, change the permeability characteristics of materials. The
penetrable ability is concerned with the deposited crystalline morphologies. Different
carboxylic acid has different modification efficiency. The number of hydroxyl group in
carboxylic acid molecular has an effect on the crystal morphologies. Compared to malic acid
and maleic acid, tartaric acid, with two hydroxyl groups in a bicarboxylate acid molecular,
has the highest crystalline morphologies modify efficiency, yielding almost round calcite
particle modified morphologies. Paste samples coated with SHPM consisting of tartaric acid
has a lowest permeability comparing to the ones consisting of malic and maleic acid, while
for the paste samples blended with magnesium salt and cured in tartaric acid dilute solution,
the permeability coefficient is highest among the three ones. The result of permeability
experiments indicates that the characteristics of carboxylic acid have influence on carbonate
salts deposition efficiency and its dissolution migration ability.
8
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
The high migration rate promoted the proliferation of deposited precipitation products in
cementitious capillary pores and fine cracks. In a leaching circumstance, there is equilibrium
between deposition and decalcification of leaching process, which determines the materials
permeability characteristics and durability performance. Particularly, in a weak acidic dryingwetting cycles circumstance, there is an equilibrium of self healing of carbonate deposition
and degradation of decalcification in cementitious materials. The test results in this research
confirmed that the leaching of alkaline ions from cementitious materials via dilute acidic
solution, without a contrary process of crystalline deposition, would significant aggravate the
materials degradation progress.
Compared to calcium carbonate, magnesium carbonate is more inclined to leach out from
cementitious materials for its tiny particle morphologies and higher solubility, and more
feasible to be suffered from acidic chemical attraction.
ACKNOWLEDGEMENTS
Authors would like to thank Doctorial candidate J. Zhou for his assistance on the permeability experiment.
Jiangsu Provincial Institute of Building also expresses his gratitude to the Department of Education of Jiangsu
Government for a grant allowing him a research visit to TU Delft.
REFERENCES
1) Nataliya Hearn, Self-sealing, autogenous healing and continued hydration what is the difference? Materials
and Structures, 1998, 31,563-567
2) Sébastien Granger, Ahmed Loukili , Gilles Pijaudier-Cabot and Mouloud Behloul ,Self healing of cracks in
concrete from a model material to usual concretes,2nd International Symposium on Advances in Concrete
through Science and Engineering,2006, 11-13
3) Natalya Hearn and C. T. Morley,Self-sealing property of concrete—Experimental evidence, Materials and
Structures, 1997, No. 30,404-411
4) Carola Edvardsen ,Water Permeability and Autogenous Healing of Cracks in Concrete, ACI Materials
Journal, 1999, 96, No. 4,448-455
5) Peter A. Claisse, Hanaa El-Sayad, and Ibrahim G. Shaaban ,Permeability and Pore Volume of Carbonated
Concrete, ACI Materials Journal, 1999. 96, No. 3,378-382
6) R. Wasserman and A. Bentur, Effect of concrete composition on durability in natural acidic environment
,Advances in Cement Research, 2006, 18, No. 4,135-143
7) A. Bertrona, G. Escadeillas, and J. Duchesne, Cement pastes alteration by liquid manure organic acids
chemical and mineralogical characterization, Cement and Concrete Research, 2004, No. 34, 1823-1835
8) A. Bertron, J. Duchesne and G. Escadeillas, Attack of cement pastes exposed to organic acids in
manure,Cement & Concrete Composites 2005, No. 27 ,898-909
9) Taylor, H. F. W, Modification of the Bogue calculation, Advances in Cement Research, 1989, 2, No.6. 7377.
10) T. Van Gerven, D. Van Baelen, V. Dutré and C. Vandecasteele, Influence of carbonation and carbonation
methods on leaching of metals from mortars, Cement and Concrete Research, 2004, 34, No. 1, 149-156
11) Ye, G. Experimental study and numerical simulation of the development of the microstructure and
permeability of cementitious materials, Ph.D. thesis, Delft University of Technology, Delft, 2003.
12) Norio Wada, Kimihiro Yamashita and Takao Umegaki, Effects of carboxylic acids on calcite formation in
the presence of Mg2+ ions, Journal of Colloid and Interface Science 1999, 212, No. 2,357-364
13) An-jian Xie, Yu-hua Shen, Xiao-yan Li, Zong-wei Yuan, Ling-guang Qiu, Chun-yan Zhang and Yuan-feng
Yang, The role of Mg2+ and Mg2+/amino acid in controlling polymorph and morphology of calcium
carbonate crystal , Materials Chemistry and Physics, 2007, 101, No. 1, 87-92
14) Jesús García-Carmona, Jaime Gómez Morales and Rafael Rodríguez Clemente, Morphological control of
precipitated calcite obtained by adjusting the electrical conductivity in the Ca(OH)2-H2O-CO2 system,
Journal of Crystal Growth ,2003, 249,No.3-4,561-571
15) C. Vernet, C. Alonso, C. Andrade, M. Castellote, I. Llorente, A. Hidalgo ,A new leaching test based in a
running water system to evaluate long-term water resistance of concretes, Advances in Cement Research,
2002, 14, No. 4, 157-168
9
© Springer 2007
Proceedings of the First International Conference on Self Healing Materials
18-20 April 2007, Noordwijk aan Zee, The Netherlands
You Youkun et al.
16) K.-J. Westin, and A.C. Rasmuson ,Crystal growth of aragonite and calcite in presence of citric acid, DTPA,
EDTA and pyromellitic acid, Journal of Colloid and Interface Science 2005, 282 , No. 2,359-369
Contact author: youyoukun@cnjsjk.cn
10
© Springer 2007