The i.e. generally is used to introduce matter that is explanatory as opposed to being the name of an example or list of examples. If you can say for example as a substitute for the abbreviation, you want to use e.g., not i.e. Do not italicize or underline these abbreviations.here is a space between the number and the abbreviation. Notice that we do not put an s after such abbreviations even when the plural is indicated. Also, we do not use a period with such abbreviations except for in. when it might be confused with the preposition in.
Chemical admixtures are used in pervious concrete to obtain special properties, as in conventional concrete. Because of the rapid setting time associated with pervious concrete, retarders or hydration-stabilizing admixtures are commonly used. Use of chemical admixtures should closely follow manufacturerâs recommendations. Air-entraining admixtures can reduce freeze-thaw damage in pervious concrete, and are used where freeze-thaw is a concern. ASTM C 494 governs chemical admixtures, and ASTM C 260 governs air-entraining admixtures.
The runoff coefficient or curve number of the paved area should be that of the subgrade soils in the compacted state. Over-compaction of the subgrade during construction will prevent necessary infiltration. Structurally, pervious concrete is weaker than plain concrete with compressive strengths less than 1000 psi. Due to the lower strengths, pervious concrete pavements are acceptable for light duty applications such as car parking facilities, pedestrian areas, and low traffic pavements.