Because of our work with Counties, we have many remote sites. Such is the nature of the business, but since concrete begins to cure the moment it gets mixed we often run into problems with the prescribed time limits for concrete travel distance. What is the limit, and what are the options for dealing with […]
Concrete Slump: Explanation, testing and Interpretation
December 6, 2013 by Leave a Comment
Concrete slump is a definition of the consistency, often called workability, of concrete. Slump Test The slump test is defined by ASTM C143 and AASHTO T119 in the United States, and EN 12350-2 in Europe. There is no significant other testing method for concrete workability in industry use today. A standard size cone (Base diameter […]
How to Calculate the Water Cement Ratio
November 28, 2013 by Leave a Comment
The water to cement ratio is the most important factor in concrete strength. The ratio is, as it’s name implies, the ratio of water to cement. If you can measure the volume of water, a common conversion is: The higher the water cement ratio, the lower the strength. But the lower the ratio, the more […]
Water Reducing Admixtures
November 27, 2013 by Leave a Comment
Water-reducing admixtures reduce the quantity of water required to produce concrete of a certain slump. They also: Reduce the water-cement ratio Reduce cement content increase slump Typically, water reducing admixtures reduce the water content by approximately 5 – 10% for the same strength properties. Effect on Strength Generally, an increase in strength is obtained with […]
Air Entraining Admixtures
November 26, 2013 by Leave a Comment
Air entraining admixtures, as you can probably guess, force air into the concrete. They result in microscopic air bubbles spread relatively evenly throughout the concrete. Reasons for Using Air Entraining Admixtures There are several reasons to have air entrainment in concrete: To improve freeze-thaw resistivity To increase resistance to de-icing chemicals To enhance the workability […]
Types of Concrete Admixtures
November 25, 2013 by Leave a Comment
Admixtures are used in almost any concrete mixture produced today. Following is a list of the most common ones: Accelerators When you need fast strength gain because other components require construction adjacent to the concrete. Accelerating admixtures shorten the setting and early-strength development time. They consist of Calcium chloride, Triethanolamine, sodium thiocyanate, calcium formate, calcium […]
Concrete Strength Factors
November 22, 2013 by Leave a Comment
The compressive strength of concrete is expressed in Megapascals (MPa) or pounds per square inch (psi) at an age of 28 days. Since the strength is constantly increasing, the reference strength chosen by industry is 28 days. Typical strengths are in the range of 25 – 35 MPa (3,600 – 5,000 psi). On my bridge […]
Types of Pipe Material
October 25, 2013 by Leave a Comment
Pipe materials are chosen to withstand internal pressures, external loads from backfill and traffic, smoothness, corrosion resistance, chemical inertness, cost, and other factors. The major types of pipe material that are in use today are: Plastic Steel Concrete Copper and brass Cast iron Vitrified clay Plastic Pipe Subdivided into PVC and ABS pipe, plastic pipe […]
What are the types of Portland Cement?
September 24, 2013 by Leave a Comment
Portland cement is the primary ingredient in concrete. It is produced by burning a mixture of lime and clay in a rotary kiln and grinding the resulting mass. ASTM C-150 describes 5 classifications of portland cement Type 1: Normal portland cement Type 2: Modified portland cement Type 3: High-early strength portland cement Type 4: Low-heat […]