May 2022 ASCE-NH Newsletter May 2022 | Page 5

“ WATER / CEMENT RATIO ”

Portland cement concrete ( PCC ) is a mixture of aggregate , air , cement , sand , and water . By changing the amount of each component , you can easily alter the properties of PCC . Therefore , it is important for engineers to take into account the required strength and application when putting together a mix design . The water-cement ratio is one of the most critical measurements an engineer looks at . Not only does it determine the compressive strength , but it also influences durability and workability . It wouldn ’ t be good if a concrete truck delivers a couple yards of 6,000psi mix for a foundation pour and the workers aren ’ t able to work it between the formwork and reinforcement .
Water-cement ratios typically range from 0.4 to 0.6 . A lower water-cement ratio results in higher compressive strength , more durability , but less workability on site . A 0.4 water-cement
1 ratio mix with air entrainment typically results in a compressive strength around 5,000psi . This mix would be more ideal for higher quality construction applications .
A high water-cement ratio results in lower compressive strength , less durability , but more workability on site . A 0.6 water-cement ratio mix with air entrainment typical results in a compressive strength around 3,000psi workability is needed .
1
. This mix could be used if strength is less critical and
1
Mamlouk , Michael . Materials for Civil and Construction Engineers . 4th Edition , Pearson , 2017 .

CLASSIFIEDS

SLR International Corporation has an exciting opportunity for a Mid-Level Geotechnical Engineer in our Bedford , New Hampshire location . If you have a minimum of 7 years of relevant work experience in Geotechnical Engineering , this opportunity might be the right fit for you ! Come join our strong team of engineers and scientists as a part of a dynamic and growing international environmental consulting organization .
Click here to apply
5