We refer to the enclosed publication by Mr. Ulli Heinlein and Prof. Dr. Thomas Freimann "Pre-applied mechanically bonded waterproofing membranes: Cement paste filtration process and influencing parameters" Our colleague Dr. Jens Glowacky worked out a "Critical discussion with questions about the publication".

1. 1|4
Dr. J. Glowacky
Telefon +49 (0) 7032 89 399 - 0
Fax +49 (0) 7032 89 399 - 29
Mail j.glowacky@bpa-waterproofing.com
Herrenberg, December 9th 2022
Critical discussion with questions about the publication:
„Pre-applied mechanically bonded waterproofing membranes: Cement paste filtration process and in-
fluencing parameters” (Heinlein, Freimann, 2022, published in the Journal of Building Engineering)

2. 2|4
Dr. J. Glowacky
Telefon +49 (0) 7032 89 399 - 0
Fax +49 (0) 7032 89 399 - 29
Mail j.glowacky@bpa-waterproofing.com
The present publication compares various polypropylene and polyether sulfone fleeces in their ability to
incorporate fresh concrete suspensions, as it is the case when concreting with FBV systems (fresh con-
crete composite system), but this has not yet been conclusively clarified. The aim is to identify parame-
ters that can influence this process. From this, direct conclusions and influencing parameters on the use
of fresh concrete composite membranes should be obtained. For this purpose, a new test setup was de-
veloped and used, in which the fleece is tested when clamped horizontally in order to enable and com-
pare the penetration of a concrete suspension with and without vibration. The concrete suspension that
has penetrated or incorporate is examined according to various aspects, also the eluate.
From the point of view of a manufacturer of pre-applied fresh concrete bonding systems (fbv systems),
there are a few critical points from the practise when considering the present work, which are listed be-
low and put up for discussion.
Fleece/nonwoven is used in building waterproofing in combination with a tight plastic membrane (PVC,
HDPE, TPO,…). The combination of these materials, e.g. thermally fixed, physically bonded, ... is not con-
sidered in this work. In practice, the goal is sealing and secure bonding with the concrete, not filtration.
The majority of fleeces reviewed in this work exhibit properties, e.g. basis weights, that would never be
used in an FBV system. Therefore, the consideration for conclusions on FBV systems is already wrong for
the aim of this work and the way the work is planned and carried out.
If a wall is constructed using the FBV system in practice, the formwork is filled with concrete from the
bottom up. This leads to a different filling geometry of the fleece in the FBV system than shown in this
work. The formation of eluate or the formation of filter cakes can almost be ruled out.
The changes in the concrete edge zone of concretes with and without FBV system are also not shown in
this work. The fleece thickness after concreting is significantly lower than the usual view of a concrete
edge zone. It therefore only plays a subordinate role with regard to the component thickness. Neverthe-
less, practical knowledge shows that a good fleece-concrete bond in the concrete edge zone results in a
denser concrete structure.
In addition to the critical perspective from building practice, also critically question of the scientific pro-
cessing must be allowed. The following points should stimulate the discussion here:
The new test setup of this work only considers the behaviour of fleece during horizontal concreting.
When using FBV systems, however, the largest part is used in the vertical area of a wall and is therefore
not taken into account with the present test setup.

3. 3|4
Dr. J. Glowacky
Telefon +49 (0) 7032 89 399 - 0
Fax +49 (0) 7032 89 399 - 29
Mail j.glowacky@bpa-waterproofing.com
Furthermore, it is not taken into account, not even in the horizontal test setup, how differently fleeces
fixed to the sealing membrane behave during concreting, since they may be subject to one-sided con-
straints through the bond and the bonding type.
In this paper the influence of formwork is not taken into account, nor is the concreting pressure caused
by concreting.
It is not explained in a comprehensible manner what statement the analysis of the eluate in the test set-
up has for construction practice if a sealing membrane prevents the described filtration with eluate for-
mation.
What happens to the liquid phase during concreting in the fleece? Shown here, the amount of liquid in
the concrete fleece layer with sealing membrane is even reduced compared to pure fleece.
The liquid phase is important for concrete hydration, changes in its composition depending on the hy-
dration stage and is usually not removed in construction practice.
In the present work, the eluates show different particle sizes and distributions, which can be traced back
directly to the concrete recipe. The use of CEM II/A-LL 42.5 N cement is a clear indicator here. The con-
tained inert limestone powder is found in the liquid phase, is mobile and can be washed out. This is a
well-known and sometimes problematic phenomenon in construction practice.
This can also have significant effects on the interaction with construction chemical products. In practice,
the use of PCE as a flow agent in particular has been critically discussed and has also been confirmed by
scientific work. Nevertheless, these superplasticizers are used in this work. As is well known, sulfonates
should be used as superplasticizers for the cements containing limestone powder used here.
The influence of the concrete composition on the penetration behaviour in fleece is not considered in
this work, although this appears to be very important from practical building experience. If this consid-
eration were initially to take a back seat, the concrete composition would have to be broken down into
a very simple, rudimentary recipe in order to greatly minimize these influences.
This is usually what drives manufacturers to improve a product system and generate demonstrably
denser concrete surfaces.

4. 4|4
Dr. J. Glowacky
Telefon +49 (0) 7032 89 399 - 0
Fax +49 (0) 7032 89 399 - 29
Mail j.glowacky@bpa-waterproofing.com
In summary, the present work represents a very rudimentary, impractical consideration of the influence
of nonwovens, which are usually not relevant for the FBV systems. The test setup and the selection of
the nonwovens examined are far away from construction practice. Furthermore, the comparative inves-
tigations on eluates and filter cakes are not relevant to practice. Using a concrete based on Portland
limestone cement, can also explain the described investigations, in part with the use of PCE superplasti-
cizers in terms of concrete technology or cement chemistry without having to show the direct influence
of the fleeces. Overall, many theoretically and practically known influencing parameters of fleeces or
FBV systems (as a combination product of fleece and sealing membrane) are not shown and discussed.
Dr. rer. nat. Jens Glowacky
BPA GmbH
Short CV:
After studying mineralogy with a focus on geochemistry, technical mineralogy, chemistry and physics
and completing a doctoral thesis in construction chemistry at the Karlsruhe Research Center, Jens
Glowacky’s post-doctoral career took him to the Karlsruhe Institute of Technology as a lecturer, project
and laboratory manager (KIT). After three industrial positions as laboratory manager and research and
development manager at mortar and paint manufacturers as well as in mechanical engineering, he has
been working in operations and laboratory management as well as development and innovation at BPA
GmbH since 2018.