Foundation pocket walls chipping/roughing before grouting 1

[realit]

We are going to do pocket grouting for a compressor. The side walls of the pockets are smooth. Will the smooth walls create any adhering problem for grout material. Grout material is : Flowgrout EP(R). We have already placed the machine on foundation. So, if we want to chip side walls of the pockets we need to lift the machine away, chip the walls and again align the skid. This would be very tedious job for us. So my question is will the grout material serve its purpose with smooth pocket walls? Will the smooth walls create any adhering problem for grout material.

 

[BigInch]

It will adhere, if the adjacent material is clean, especially meaning free from oil. Problem is how long. Vibration of the compressor will eventually weaken the interface and, as the surface will be uniform and a flat plane any force applied on that plane will not be able to be resisted by intergranular frictional forces, only the shear stress of the grout. Dripped oil, a big trouble maker for concrete in pump and compressor foundations, is also likely to enter the interface and speed things along. Not to mention that there is a possibility that the underlying layers of the adjacent concrete surface may be saturated with oil as well. The region can also be subject to temperature stress from the hot machinery above. Every manufacturer I know recommends chipping adjacent concrete surfaces to obtain the best bond possible. There's probably a really good reason for that.

 

[realit]

Thanks BigInch

 

[Dam14]

Hello,
I have this problem right now regarding the ship unloader rail foundation @ jetty that was already grouted with Sika 215, although its surface was rough but it was not chipped. My question is, Does it affect the purpose of the grout with this condition? see attached drawing (pdf file)for more info. the ship unloader weighs about 900 tons and the base plate of the rail was anchored with j bolt that was embedded in the concrete. please help me analyze this problem. if there is any justification with reference or calculation it will be a big help.

 

[BigInch]

It is possible, but probably not so much since this does not look like you will have compressor, pump, or other cyclic machine vibration loads where high tension load is introduced. It looks to me that the grout there is mostly used for leveling purposes of the plate only and should be in compression (most) all of the time, however any bonding to concrete should always be done over a chipped surface for maximum adhesion.

 

[Dam14]

Thank You Very Much BigInch.