"clay" soil can be a pretty complex subject, and it's not st all easy to fix by adding store-bought additives unless what you're happening to,be adding is what happens to be needed. The gardening world is packed with gimmicky money sucking unneeded additives. The introductory paragraph on the ClayMend page is a marvel of pure BS.

Clay is really a structural problem. Look into the proportions of "normal" soils verses your clay soil / OM mix, and you may notice a lack of intermediate particles in it. That's sand. I claim that a HUGE addition of sand can help with the soil structure, but the additions can approach 50%. People will disagree.

It is difficult to say what those products are because what is posted does not say what is in them. They are liquids and liquids do not replace organic material.

I have not, yet, seen anything from any soil scientist that recommends adding sand to clay soil. They do say that if sand is used to add somewhere between 45 and 75 percent, by volume and that is a lot of sand.

You say adding leaves has not helped. How much has been added? To achieve 6 to 8 percent organic matter in soils means a lot of organic material (those leaves) must be added. Perhaps this article, written by Keith Baldwin, phD in soil science, might be of some help. http://www.finegardening.com/improving-clay-soils

Perhaps, too, these simple soil tests may be of some help.

1) Soil test for organic
material. From that soil sample put enough of the rest to make a 4 inch level in
a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and
replace the lid, tightly. Shake the jar vigorously and then let it stand for 24
hours. Your soil will settle out according to soil particle size and weight.
For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the
bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above
that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole
1 foot square and 1 foot deep and fill that with water. After that water drains
away refill the hole with more water and time how long it takes that to drain
away. Anything less than 2 hours and your soil drains’ too quickly and needs
more organic matter to slow that drainage down. Anything over 6 hours and the
soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful
of your slightly damp soil and squeeze it tightly. When the pressure is
released the soil should hold together in that clump, but when poked with a
finger that clump should fall apart.

4) Smell. What does your
soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant
odor? The more organic matter in your soil the more active the soil bacteria
will be and the nicer your soil will smell, to a point. Too much organic matter
can be bad as well.

5) Life. How many
earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5,
according to the Natural Resources Conservation Service, indicates a soil that
is not healthy.

Keep adding organic material.

kimmq is kimmsr

I started with clay loam and perhaps some silty clay loam. it was good soil, but some areas were a little wet at times and sometimes some of it too lumpy.

I added 3 inches of sand and 4 inches of local sphagnum peat moss....instant loose dream soil. Of course I do add a lot of organic matter too.

I have had good success with cover crops to build up clay soils into something different. Oats, oilseed radish, rye, clovers, etc.

In my experience there's no quick way. If you incorporate shredded leaves every year you will have super soil after ten years. Believe me, ten years passes very quickly. And you're fortunate, clay is incomparable in its ability to hold nutrient minerals (although I must say compost is a near equal). Regards, Peter.

Adding sand to a clay soil starts to change it when the sand content becomes 50%. How much sand you have to add to get to that point depends on how much sand is already in the soil before you start.

Dumping lighter soil on top of the clay soil, planting in that - without blending the two soils together - or digging out the clay soil, replacing it with lighter soil is much more direct than trying to change the existing soil by mixing things into it.

I have yet to find a soil scientist, someone who knows about soil, that would recommend adding sand to clay soils. They will tell you that if you are going to add sand to clay then it should be3 in that area of 45 to 75 percent sand by volume. Adding that much sand to your already existing yard will raise the level a considerable distance because you are adding feet of sand not just inches.

I have worked with clay soils and have seen that adding organic matter can begin to make changes in one year, although it can take 3 to 5 (not 10) to make a good workable soil.

kimmq is kimmsr

kimmq, I have had excellent instant results with what I have posted above. I have done this in bed after bed through about 10 years.... 3 inches of added sand and 4 inches of local sphagnum peat moss. Also add organic like you should anyway as the sand and peat moss are not very nutrient heavy, but they make the soil to be dream soil in tilth. Yes, I mix it all deeply together.

The only quick clay buster I've found so far is ants. Just regular old ants. I had some colonies turn up when I started covering and nourishing my soil by composting in place, but not quite getting it wet enough. Those tiny tractors settled in and just tore up everywhere they went. To be clear, this was NOT light work; I broke a hand tiller on this clay when the steel buckled before the clay would shift.

Maybe you should look up which ant species are local to your area, and try to attract them. When you need them to move on so you can work the area, flood it.

Yes, clay particles are flat, stack themselves tightly. A major problem with keeping (instead of working on top of/replacing) an existing soil of strong character (too much clay or sand), loosening it with organic material is that you have to keep replacing the organic matter.

The need to replace the organic material in soils is not a "problem" it is the normal part of the process. One adds organic material to soil for several reasons and the Soil Food Web digests that organic material to make the nutrients that OM contains available to the plants growing in that soil.

Calcium works in sodic soils and in no others.

kimmq is kimmsr

I don't see how replacing the organic material is a problem. If you're gardening on the soil, you're going to have material you're not using, just put it back (or save time and effort and just never remove it). If you receive anything made of paper or cardboard, you can put it on the plot about as easily as you could put it in the trash can. If you have any decorative plants that requite trimming back (such as a lawn), the stuff you cut off has to go somewhere, it might as well be gathered up and put where it will do you good. And when/if you do import organic material, one often-free option available in bulk also lasts a long time before it breaks down completely, and helps hold moisture in place to save you water and the time and effort to apply it: wood chips from a local tree trimmer service have to be dumped somewhere, it might as well be at your house for mulch.

The materials that improve texture also improve structure. Things that improve texture of clayey soils are organic matter from a variety of sources, calcium bearing compounds, peat moss, and permanent materials like sand. I believe in all of them.