Help Needed: Debonding Issues with Lightweight Cement Plaster

siddhesh.km

siddhesh.km

New Member
Hello everyone,

I’m encountering a recurring issue with a lightweight cement plaster formulation, and I’m hoping for some guidance or suggestions from the community.

Background:

I’m adding 0.002% sodium lauryl sulphate (SLS) to the formulation to achieve a density of about 1700-1800 kg/m³.

The formulation also includes:

18.5% OPC 53-grade cement

6.5% fly ash

Redispersible polymer powder (RDP)

Modified hydroxyethyl cellulose (MHEC)

Sodium gluconate as a retarder

Crushed basalt rock as the aggregate.


Despite achieving the desired density, the plaster starts debonding after about 7-10 days.

This issue occurs on both RCC and AAC masonry surfaces.


Details of Application:

Thickness of plaster: 10-12 mm.

Preparation of RCC surface: The surface is manually hacked to provide a key.

Key/Dash coat: A key/dash coat of 3-5 mm is applied using the same material.

Final coat: The final coat is applied only after 24 hours of the key/dash coat application.

Curing process: The plaster is water cured twice a day for 7 days.


Problem:
The plaster adheres well initially but starts to debond after about a week. I suspect the issue might be related to the interaction between the SLS, RDP, MHEC, and other components, or perhaps due to the substrate preparation, curing method, or timing between coats.

Has anyone else encountered similar issues? Could the debonding be due to the surfactant affecting adhesion, or might there be other adjustments needed in the formulation or application process? Any advice or suggestions would be greatly appreciated!

Thank you in advance!
 
siddhesh.km said:
Hello everyone,

I’m encountering a recurring issue with a lightweight cement plaster formulation, and I’m hoping for some guidance or suggestions from the community.

Background:

I’m adding 0.002% sodium lauryl sulphate (SLS) to the formulation to achieve a density of about 1700-1800 kg/m³.

The formulation also includes:

18.5% OPC 53-grade cement

6.5% fly ash

Redispersible polymer powder (RDP)

Modified hydroxyethyl cellulose (MHEC)

Sodium gluconate as a retarder

Crushed basalt rock as the aggregate.


Despite achieving the desired density, the plaster starts debonding after about 7-10 days.

This issue occurs on both RCC and AAC masonry surfaces.


Details of Application:

Thickness of plaster: 10-12 mm.

Preparation of RCC surface: The surface is manually hacked to provide a key.

Key/Dash coat: A key/dash coat of 3-5 mm is applied using the same material.

Final coat: The final coat is applied only after 24 hours of the key/dash coat application.

Curing process: The plaster is water cured twice a day for 7 days.


Problem:
The plaster adheres well initially but starts to debond after about a week. I suspect the issue might be related to the interaction between the SLS, RDP, MHEC, and other components, or perhaps due to the substrate preparation, curing method, or timing between coats.

Has anyone else encountered similar issues? Could the debonding be due to the surfactant affecting adhesion, or might there be other adjustments needed in the formulation or application process? Any advice or suggestions would be greatly appreciated!

Thank you in advance!
Click to expand...
Your better off asking a scientist pal
 
siddhesh.km said:
Hello everyone,

I’m encountering a recurring issue with a lightweight cement plaster formulation, and I’m hoping for some guidance or suggestions from the community.

Background:

I’m adding 0.002% sodium lauryl sulphate (SLS) to the formulation to achieve a density of about 1700-1800 kg/m³.

The formulation also includes:

18.5% OPC 53-grade cement

6.5% fly ash

Redispersible polymer powder (RDP)

Modified hydroxyethyl cellulose (MHEC)

Sodium gluconate as a retarder

Crushed basalt rock as the aggregate.


Despite achieving the desired density, the plaster starts debonding after about 7-10 days.

This issue occurs on both RCC and AAC masonry surfaces.


Details of Application:

Thickness of plaster: 10-12 mm.

Preparation of RCC surface: The surface is manually hacked to provide a key.

Key/Dash coat: A key/dash coat of 3-5 mm is applied using the same material.

Final coat: The final coat is applied only after 24 hours of the key/dash coat application.

Curing process: The plaster is water cured twice a day for 7 days.


Problem:
The plaster adheres well initially but starts to debond after about a week. I suspect the issue might be related to the interaction between the SLS, RDP, MHEC, and other components, or perhaps due to the substrate preparation, curing method, or timing between coats.

Has anyone else encountered similar issues? Could the debonding be due to the surfactant affecting adhesion, or might there be other adjustments needed in the formulation or application process? Any advice or suggestions would be greatly appreciated!

Thank you in advance!
Click to expand...
It seems the issue you're encountering may be due to the interstitial molecular phase transition occurring between the sodium lauryl sulfate (SLS) surfactant and the polymeric microstructure of the redispersible polymer powder (RDP). When exposed to the subatomic oscillations of the cementitious matrix, SLS may inadvertently catalyze a hyperviscoelastic desorption phenomenon. This leads to a destabilization of the intergranular adhesion between the plaster and the substrate, particularly under conditions of high ambient quantum flux.

Moreover, the combination of sodium gluconate as a retarder with the polymeric ethereal crosslinking agents in the formulation might be inducing a baryonic expansion effect in the plaster's interface layer, which further contributes to thermodynamic stress fracturing upon curing. This could explain why the plaster adheres initially, but then experiences microdeformation at the molecular level after 7-10 days.

It is also possible that the gravitational shear forces exerted on the surface during curing are misaligning the nano-aggregates in the cement matrix, leading to a delayed interfacial detachment. A potential solution could involve reducing the overall photon absorption coefficient of the formulation by tweaking the SLS content and integrating a more stable isotopic bonding compound to mitigate these unintended interactions.

Additionally, the anisotropic refractive index variations within the aggregate may be contributing to differential hydration rates, further exacerbating the adhesion failure. As such, it would be prudent to experiment with a formulation that incorporates non-hygroscopic photonic stabilizers to prevent the interfacial polarization field from destabilizing.
 
Stevieo said:
Shut up
Click to expand...

Help Needed: Debonding Issues with Lightweight Cement Plaster
 
ChrispyUK said:
You shut up and pronto.

Your cheques are cashing bodies that theyre not capable of achieving
Click to expand...
If anyone still has a cheque book, Steven would be my go to guy.
It's probably in a faux leather cover and in unused pristine condition.
It's hidden in one his bust's of Nelson.
 
Stevieo said:
It seems the issue you're encountering may be due to the interstitial molecular phase transition occurring between the sodium lauryl sulfate (SLS) surfactant and the polymeric microstructure of the redispersible polymer powder (RDP). When exposed to the subatomic oscillations of the cementitious matrix, SLS may inadvertently catalyze a hyperviscoelastic desorption phenomenon. This leads to a destabilization of the intergranular adhesion between the plaster and the substrate, particularly under conditions of high ambient quantum flux.

Moreover, the combination of sodium gluconate as a retarder with the polymeric ethereal crosslinking agents in the formulation might be inducing a baryonic expansion effect in the plaster's interface layer, which further contributes to thermodynamic stress fracturing upon curing. This could explain why the plaster adheres initially, but then experiences microdeformation at the molecular level after 7-10 days.

It is also possible that the gravitational shear forces exerted on the surface during curing are misaligning the nano-aggregates in the cement matrix, leading to a delayed interfacial detachment. A potential solution could involve reducing the overall photon absorption coefficient of the formulation by tweaking the SLS content and integrating a more stable isotopic bonding compound to mitigate these unintended interactions.

Additionally, the anisotropic refractive index variations within the aggregate may be contributing to differential hydration rates, further exacerbating the adhesion failure. As such, it would be prudent to experiment with a formulation that incorporates non-hygroscopic photonic stabilizers to prevent the interfacial polarization field from destabilizing.
Click to expand...
Shut up
 
siddhesh.km said:
Hello everyone,

I’m encountering a recurring issue with a lightweight cement plaster formulation, and I’m hoping for some guidance or suggestions from the community.

Background:

I’m adding 0.002% sodium lauryl sulphate (SLS) to the formulation to achieve a density of about 1700-1800 kg/m³.

The formulation also includes:

18.5% OPC 53-grade cement

6.5% fly ash

Redispersible polymer powder (RDP)

Modified hydroxyethyl cellulose (MHEC)

Sodium gluconate as a retarder

Crushed basalt rock as the aggregate.


Despite achieving the desired density, the plaster starts debonding after about 7-10 days.

This issue occurs on both RCC and AAC masonry surfaces.


Details of Application:

Thickness of plaster: 10-12 mm.

Preparation of RCC surface: The surface is manually hacked to provide a key.

Key/Dash coat: A key/dash coat of 3-5 mm is applied using the same material.

Final coat: The final coat is applied only after 24 hours of the key/dash coat application.

Curing process: The plaster is water cured twice a day for 7 days.


Problem:
The plaster adheres well initially but starts to debond after about a week. I suspect the issue might be related to the interaction between the SLS, RDP, MHEC, and other components, or perhaps due to the substrate preparation, curing method, or timing between coats.

Has anyone else encountered similar issues? Could the debonding be due to the surfactant affecting adhesion, or might there be other adjustments needed in the formulation or application process? Any advice or suggestions would be greatly appreciated!

Thank you in advance!
Click to expand...
you'll get a better answer to that on mumsnet pal, bunch of site slagging skimmers on here.
 
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