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Ferrocement or ferro-cement [1] is a system of construction using reinforced mortar [2] or plaster (lime or cement, sand, and water) applied over an "armature" of metal mesh, woven, expanded metal, or metal-fibers, and closely spaced thin steel rods such as rebar. The metal commonly used is iron or some type of steel, and the mesh is made with ...
Concrete is a mixture of coarse (stone or brick chips) and fine (generally sand and/or crushed stone) aggregates with a paste of binder material (usually Portland cement) and water. When cement is mixed with a small amount of water, it hydrates to form microscopic opaque crystal lattices encapsulating and locking the aggregate into a rigid shape.
Pores (the spaces that exist between soil particles) provide for the passage and/or retention of gasses and moisture within the soil profile.The soil's ability to retain water is strongly related to particle size; water molecules hold more tightly to the fine particles of a clay soil than to coarser particles of a sandy soil, so clays generally retain more water. [2]
Beginning in the 20th century, designers of industrial and municipal sewage pollution controls typically utilized engineered systems (e.g. filters, clarifiers, biological reactors) to provide the central components of pollution control systems, and used the term "BMPs" to describe the supporting functions for these systems, such as operator training and equipment maintenance.
Water retention curve is the relationship between the water content, θ, and the soil water potential, ψ. The soil moisture curve is characteristic for different types of soil, and is also called the soil moisture characteristic. It is used to predict the soil water storage, water supply to the plants (field capacity) and soil aggregate stability.
A water-saturated interior resists the further movement of vapor into the mass of the concrete. If the condensation rate of vapor is much faster than the escaping speed of vapor out of concrete due to sufficiently high heating rate or adequately dense pore structure, a large pore pressure can cause spalling.
Example of flat piece of concrete having dislodged with corroded rebar underneath, Welland River bridge across Queen Elizabeth Way in Niagara Falls, Ontario. The expansion of the corrosion products (iron oxides) of carbon steel reinforcement structures may induce internal mechanical stress (tensile stress) that cause the formation of cracks and disrupt the concrete structure.
It also causes water bleeding at the surface of concrete slabs or rafts (with a dusty surface left after water evaporation). For all the afore mentioned reasons, it is strictly forbidden to add extra water to a ready-mix concrete truck when the delivery time is exceeded, and the concrete becomes difficult to pour because it starts to set. Such ...