Estimating Total Concrete Volume

Estimating Total Concrete Volume

To estimate the cubic yardage of concrete needed, first calculate the area in square feet,  If the area is larger than 300 sq. ft., first find the volume for 300 sq. ft., then find the volume for the remainder of the square footage, and add the two together. To allow for slight irregularities in concrete thickness and for some spillage and waste, round up at least to the next whole or half cubic yard measure, allowing a mini-mum of 5–10%  extra.

Ready mix suppliers will need to know minimum compressive strength and maximum aggregate size for the concrete mix, and any special requirements such as air entrainment for added freeze thaw durability. As a general guideline for ordering ready mix concrete. Local conditions can change within a very short distance, particularly in mountainous regions, and may be more or less severe than indicated by the regional classification. Severe exposures are those in which deicing salts are used because of significant snowfall combined with extended periods in which natural thawing does not occur. If you are in doubt about which classification applies, always use the more severe exposure.

Some Uses of Concrete

Some Uses of Concrete

Concrete is relatively cheap and durable and can be molded to any shape. It can be made porous or watertight, heavy or light, and will even harden under water. These and other variable characteristics of concrete make it ideal for many uses.

Concrete building components in standard sizes are made in advance and then put in place. They include wall panels, doorsills, beams, and floor slabs. Roads made of concrete are durable and can be maintained inexpensively. Lightly traveled roads, airport runways, and irrigation canal linings are often made with a type of concrete called soil cement. Grout, or waterproof concrete, is a mixture of cement and water to which sand is often added. It may be used to help support oil-well casings or strengthen dam foundations. Asbestos cement, a lightweight concrete, is used for making shingles, sheathing, and other construction materials. It can be sawed like wood.

Concrete for Traffic Areas

Concrete for Traffic Areas

Concrete for traffic areas has many applications and is often installed as an alternative to blacktop because of its durability and other advantages.

The uses of concrete for traffic areas:

• Conventional road building
• Concrete roundabouts
• Runways
• Industrial floors

When concrete is used for these applications, the concrete layer acts as both a load bearing and a wearing course. To meet the requirements for both courses, the concrete must have the following properties:

• High flexural strength
• Freeze/thaw resistance
• Good skid resistance
• Low abrasion

The composition is a vital factor in achieving the desired requirements. The criteria for selection of the various constituents are as follows:

• Aggregate

–       Use of low fines mixes

–       Use of a balanced particle size distribution curve

–       Crushed or partly crushed aggregate increases the skid resistance and flexural strength

 

• Cement

–       Dosage 300–350 kg/m³, usually CEM I 42.5

• Additives

–       Silica fume for use in heavily traffic areas or to increase the durability generally

–       Increase in the skid resistance by spreading silicon carbide or chippings into the surface

Concrete for traffic areas is a special concrete and the following points require special attention:

–       Large areas are often installed using paving machines. The consistence must be suitable for the type of machine

–       Improvement in skid resistance by cut grooves or brush finishing

–       Thorough curing is essential