Hot Weather Concreting

ACI 305 “Hot Weather Concreting” defines hot weathers as any combination of the following conditions that tends to impair the quality of the freshly mixed or hardened concrete: The success of many hot-weather concreting operations depends on the steps taken to slow the cement hydration reactions within the concrete and to minimize the rate of evaporation of

Creep in Concrete and Effects of Creep of Concrete

Concrete creep is defined as: deformation of structure under sustained load. Basically, long term pressure or stress on concrete can make it change shape. This deformation usually occurs in the direction the force is being applied. Like a concrete column getting more compressed, or a beam bending. Creep does not necessarily cause concrete to fail or break apart. Creep

Precipitation And Factors Affecting Precipitation

It is defined as the fall of moisture from the atmosphere to the earth surface in any physical form. Usually precipitation is in two forms: Liquid - rainfall Solid Precipitation

Algal Growth & Surface Water Quality

Algae are photosynthetic organisms that occur in most habitats. They vary from small, single-celled forms to complex multi-cellular forms, such as the giant helps that grow to 65 meters in length. Algae are a large group of complex-celled photosynthetic organisms.

Durability of Concrete and Effects of Durability of Concrete

Durability is defined as the capability of concrete to resist weathering action, chemical attack and abrasion while maintaining its desired engineering properties. It normally refers to the duration or life span of trouble-free performance. Different concretes require different degrees of durability depending on the exposure environment and properties desired. For

Workability of Concrete and Factors Affecting Workability

Workability is one of the physical parameters of concrete which affects the strength and durability as well as the cost of labor and appearance of the finished product. Concrete is said to be workable when it is easily placed and compacted homogeneously i.e without bleeding or Segregation. Unworkable concrete needs more work or effort to be compacted in place, also

Methods of Transportation of Concrete

Transporting the concrete mix is defined as the transferring of concrete from the mixing plant to the construction site. The main objective in transporting concrete is to ensure that the water-cement ratio, slump or consistency, air content, and homogeneity are not modified from their intended states. Concrete produced from a mixer is required to be transported to the

Standard Compaction Test and Modified Compaction Test

Soil is compacted into a mould in 3 - 5 equal layers, each layer receiving 25 blows of a hammer of standard weight. The apparatus is shown in Figure 1 above. The energy (compactive effort) supplied in this test is 595 kJ/m3. The important dimensions are:

De Icing of Concrete

It is similar to freezing and thawing action In winters to remove the ice over large structures e.g. deck of bridge etc the chemical sodium chloride NaCl or calcium chloride CaCl2 is added these chemicals decrease the freezing point of water and the ice melts. When ice melts they get dissolved in it. A super saturated solution (called brine if NaCl is used) is formed over the

Precautionary Measures for Dams

Dams are considered to be a vital element for the economic and energy growth of any country. As compared with other sources of energy the Hydel energy proves to be more cheap and environment friendly. Being massive structures dams are needed to be deal with intense care and precautions in order to avoid any unpleasant event.

Sub-Surface Movement of Groundwater

Water moves primarily downward due to gravity. Water infiltrates from surface and moves downward to water table or ponds on impermeable surface (clay layer, etc.) to form a Perched water table

Factors Affecting Stability of Road Pavements

The thickness of pavements depends on a number of variables, but from experience it has been found that the following factors affect the performance of pavements to a great extent. Traffic Factors, Soil Factors, Environmental Factors, Stress Distribution Factors.. Traffic is the most important factor in the pavement design. The key factors include contact pressure

Factors Affecting Crop Water Requirements

A certain crop grown in a sunny and hot climate needs more water per day than the same crop grown in a cloudy and cooler climate. There are, however, apart from sunshine and temperature, other climatic factors which influence the crop water need. These factors are humidity and wind

Factors Affecting Selection of Construction Materials

Any material used for a construction purpose in the form of solid, semi-solid or liquid, processed or unprocessed (raw material) is known as construction material. A material engineer must be familiar with a wide range of materials used in a wide range of structures and is responsible for the following jobs with certain limits of compromises to be made on site.

Level of Service and Factors Affecting LOS

LOS is a scale which defines the operating conditions on highway. It is a measure of the restrictive effects of the increased volume, level of service as proposed by manual ranges from A to F, A is ideal level and F is worst level of service.