Most concrete you see is a pale gray, the dullest hue on earth. But concrete can be colorful, and there are three ways to make it that way.
INTEGRAL COLORING - Adding pigment to the concrete as it is mixed gives it color clear through that can't wear off. You can order ready-mix precolored, or mix your own using pigments. Colored ready-mix costs about $6 a yard more than plan gray. Your dealer should have samples of colored concrete to show you, but don't expect the mix you buy to match the sample perfectly. Mixing your own is no harder than mixing uncolored. If you measure carefully, you can make up test batches to find a formula for the exact color you want.
For light colors you should use white sand and white cement. Use about two percent pigment for pastels; double or triple that amount for stronger colors. For earth tones you can get by with ordinary sand, and dark somber colors as well as gray and black can be made with ordinary gray cement.
DUST-ON-COLOR - This is cheaper than integral coloring, but still gives reliable, durable color. It's based on powered dust-on mixtures sold in 100-pound bags by masonry supply outlets. You sprinkle the powder onto freshly poured concrete after the surface water has disappeared, then trowel the dust in with an aluminium or magnesium float. Overtrowelling will bring water to the surface and cause uneven coloring, so don't towel any more than necessary to work the powder in. Follow with another, lighter dusting, then towel again.
STAINING AND PAINTING - These are the cheapest and easiest ways to color concrete, and the only ways to color existing concrete. But the colors are not as permanent and the stains are rarely as bright. Paints give you the widest assortment of colors and the brightest tones of all.
Special metallic-salt type stains made specifically for concrete are the most durable - in a mild climate they last 10 years. But don't try them on concrete more than a year old or they won't react chemically to produce the desired color.
Paints for concrete come in variety of types. Some are formulated to waterproof as well as color. Some are intended for exterior walls only, others for exterior and interior walls, and still others for walls, floors and slabs. Some floor paints are no good for garage floors - car tires will lift them. Others work well on concrete above ground, but not on slabs or on concrete below ground. Read labels and ask questions before you buy.