Im not into much hardscaping. I have a large job for garden to complete in a month. The customer has requested the sidewalk area be lined with block about a foot high and raise up the garden bed area. I plan to use 2 retaining wall block high and a flat 2" wider block for the top, as if someone wanted to sit on it it wouldnt fall apart or wobble. Can strait cement, sand, lime be used in thin layers to get everything to stay together. People wont be really sitting or walking on it "hopefully" but just in case. Thanks for the comments!