Concrete Pad Surfaces

[1voyager1]

The last few months it has become very apparent that areas of our concrete pads, sidewalks, etc, are eroding away.
The concrete surfaces are being removed with the sand content being exposed as the new surface material.
It is happening just in the areas exposed to rainfall.

When we bought 6 years ago, it was mildly apparent then.
At that time, the concrete was 14 years or less old.
It looks to have increased dramatically since the eruption.
My suspicion is that the rains are washing volcanic gasses, or something similar, down out of the air, maybe even evolved from the soil after the gas inundations during the eruption, that are causing the problem.
This is in spite of those that are supposed to know saying that gas evolution is at the lowest rate it has been for many years and will continue to be so be for many more.

Am I simply a a wack-job?
Or, is there something going on?

[Rob Tucker]

I'm wondering of your concrete work was hand mixed with Quickcrete or a poured job from a concrete truck.

[1voyager1]

I was given a set of photos of the house area a year or two ago by the previous owner.
They were dated 2006.
All the slabs were in place, house slab, garage entry slab [15' x 20'], lenai slab [12' x 60'], sidewalks [73' x 3'], and spa slab [12' x 12'], a total of 1400 sq-ft +/- of slab above what is under the house and garage.

Garage entry and 67' of sidewalks are on the tax page.
Lanai and spa structures were added later, after the photos, and are entirely unpermitted.
The lanai was added as an after thought after living in it for a while.

Little doubt the garage slab and sidewalks were put in by a readymix outfit when house was built.
Steps by the back doors, on the tax page and original drawings, were removed to put the lanai in.
They are still scattered around the property.

They may have used a mixer to put in the lanai complex, almost 900 sq-ft.
That's a lot of concrete.
I think it was probably also brought in by a readymix outfit.
They may have done the after delivery handwork themselves.
The leveling of the lenai surface is not as good as I would have expected a contractor to do.

Never the less, the problem is on all exposed concrete, original and added, and looks about the same everywhere.

[kalakoa]

all exposed concrete ... about the same everywhere

Believe this is "just" the rain: incessant, slightly more acidic (and occasionally very acidic). Mostly the incessant part.

Datapoint: random precast concrete that's been left exposed. Rough texture, exposed sand, and well on its way to having that charcoal-black finish seen all over town.

[1voyager1]

@kalakola
I was wondering the same possibility.
The only problems are that USGS says sulphur gas is now at it s lowest evolution rate in many years, rainfall should be less acidic now, and the accelerated erosion rate has become very evident in the last month or two even though the eruption has been over for 4 or 5 months now.

It is possible that the erosion through the years has been enough that it is just now becoming evident.
The areas under cover seem to be OK.

EDIT:
My replies will be sporadic.
I spilled a glass of milk into my computer.
I've diagnosed it and salvaged what I can.
Got the new parts on order.
It'll be a week or two before everything gets here and rebuilt.
I have been able to pull the mobo out and jury rig it up to get some basic operations, but don't have full usage back yet.

[kalakoa]

I suspect it's really the incessant nature of the rainfall here. In some cases it creates standing water.

As for the computer: upgrade to a NUC, use the included VESA bracket to hang it off the back of the monitor, that way it's safely above the desk, much more difficult to spill things on it...