Damp cinder block walls are most noticeable after inclement weather wind-driven rain, substantial heavy rains, water-soaked ground, saturated zones, and high-water tables. Making matters worse, only a thin wall (1-1/4 inch) separates the hollow cores of the block from the cores filling up with water. In comparison to blocks, good quality, newly poured concrete foundation walls (8-10″ in thickness) are impermeable to water (0.4-0.3 perms). Heavyweight concrete blocks are semi-permeable (5 perms) and less so when the hollow cores are filled and packed with a slurry mix of concrete (about 2 perms). Cinder blocks are classified as permeable to water and water vapor (+10 perms). Lightweight blocks cannot be used in retaining walls or exterior building walls because they readily seep water.Ī cinder block is much more porous compared to a standard concrete block or poured concrete. ![]() Haydite Blocks – Another example of an expanded shale product.Split-faced Blocks – Have a rough, stone-like texture on one face of the block instead of a smooth face.Lightweight CMUs – Gravel is replaced with shale or clay expanded at extreme temperatures which makes the blocks much lighter at 22 to 28 lbs.This is why they are often used in interior non-moisture construction or outdoors for barrier walls, hardscape, and fences. However, cinder blocks are more subject to moisture, water seepage, radon gas, salt deposits, and efflorescence (white powdery residue) problems because of their high porosity. Compared to a heavyweight concrete block, a typical cinder block weighs only 26-33 lbs. There are builders that prefer cinder blocks because they are much easier to work with. Modern cinder blocks are usually made with volcanic pumice instead of cinder unless there is a nearby coal-fired power station or cement kiln to supply pulverized cinders or fly ash. “Cinder block” is an archaic term from the time when power plants and coke ovens in steel mills produced huge amounts of “cinders” from burning coal. Lower density blocks may use industrial wastes, such as fly ash or bottom ash as an aggregate instead of the sand or fine gravel used to make true concrete. ![]() The typical high-density concrete block (8 x 8 x 16 inches with two cores) weighs 36-42 lbs. Compared to typical structural concrete, they are made with a higher percentage of sand and a lower percentage of gravel and water for a stiffer mixture that holds its shape when removed from the block mold. Standard (high-density) concrete blocks are made from cast concrete – Portland cement, sand, and gravel. CMU’s may look similar, but there are big differences among them! ![]() Employing reinforcement bars and filling the hollow cores with concrete results in strong structural walls. CMUs are used for the construction of load-bearing foundation walls, basement walls, partition walls, exterior walls, retaining walls, and non-load-bearing partition walls. Concrete blocks and cinder blocks, as well as split face blocks and lightweight blocks, are all referred to as CMUs (concrete masonry units).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |