Some of the Methods Used to Increase the Strength of Concrete

The strength of concrete can be increased by a number of methods including using a higher grade of cement or a mineral admixture such as ground granulated blast furnace slag (GGBS).  It can also be strengthened by using a low water to cement ratio (W/C) as well as by using well-graded angular aggregates.  

Adding more cement to the mix or reducing the ratio of water to cement in the cement paste are two of the easiest ways to strengthen concrete.  “Every desirable physical property that you can measure will be adversely affected by adding more water,” so explains the Portland Cement Association.  The strength of concrete is also influenced by the quality of raw materials, the ratio of coarse/fine aggregate, temperature, relative humidity, compaction of concrete and the curing process.    

The quality of the aggregate is recognized by the size, shape, texture and strength of the material and the coarse/fine aggregate ratio will determine the amount of water that is needed.  When the amount of fine aggregate is increased in relation to the coarse aggregate, the aggregate surface increases and demands more water.  This means the water/cement ratio is increased, which decreases the compressive strength of the concrete.   

The cement used in the mix should be stored under dry conditions and be manufactured using the most appropriate standards.  Even the purity of the water used in the mix can have an effect on the strength of the concrete.  Another factor that impacts strength is the compaction of concrete because if there is poor compaction of the plastic concrete; air is entrapped and reduces the strength of the concrete.  If concrete contains 10% trapped air, it is estimated that the strength of the concrete can be affected by as much as 30 to 40%.   

Furthermore, to allow concrete to reach its maximum strength, concrete contractors take into account the air temperature, relative humidity and wind speeds at the time the concrete is poured and in the early curing period.  Higher temperatures allow concrete to gain strength more quickly but the final strength is actually lower when hydration occurs at too fast of pace.  It also sets up the danger of shrinkage and cracking.  Newly placed concrete may be periodically ponded, sprayed, or misted with water or a membrane-forming curing compound or covered with curing sheets.   

At The Conco Companies, we are one of the leading concrete contractors in the Western U.S. and offer a wide range of quality services and products.  Our experience includes providing services for commercial, educational, parking and other construction development as well as public works projects.  We serve California, Washington State, Oregon, Colorado and Nevada.

Sources:

quora.com/What-are-some-ways-to-increase-the-strength-of-a-concrete

cement.org/for-concrete-books-learning/concrete-technology/faqs

theconstructor.org/concrete/factors-affecting-strength-of-concrete/6220/