What is a pooled sample?
The engineers’ code of ethics requires us to “hold paramount the safety, health, and welfare of the public“. Here’s one way public health officials use statistics to do just that. […]
Testing
Hot-weather concreting
As the weather warms up, it’s good to review best practices for hot-weather concreting. The American Concrete Institute defines hot-weather concreting as “one or a combination of the following conditions […]
Making use of marginal fly ash
Electric utilities are under pressure to reduce carbon emissions and other pollutants from their power stations. More and more, they are shutting down their coal-fired plants in favor of natural […]
How many cylinders: a pot roast story
How many cylinders does it take to determine the compressive strength of concrete for acceptance testing? To quote ACI 318, A strength test shall be the average of the strengths […]
Concrete “permeability” tests
For the most part, so-called concrete “permeability” tests measure something other than permeability. Permeability is the ease with which fluids can move through a porous material. That matters because most […]
Concrete sample size: how big is big enough?
When you submit a concrete sample for petrographic examination, how big a sample do you need? That is, what’s the appropriate concrete sample size? We’ve discussed in previous posts how […]
Do we expect too much from ASTM C1202?
We often — mistakenly — refer to ASTM C1202, “Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration,” as the Rapid Chloride Permeability test. Permeability […]
ASTM C1709 promotes sustainability
ASTM C1709 provides a way to introduce alternative supplementary cementitious materials (ASCMs) into the marketplace. Supplementary cementitious materials include fly ash, slag cement, silica fume, and calcined clay. They can […]
Predict service life with ASTM C1556
ASTM C1556 is a test we use to assess the ability of concrete to resist the ingress of chloride ions. If we’re designing a high-performance concrete for a new parking […]
NT Build 492 provides data for durable concrete
NT Build 492 is a test that determines the diffusion coefficient of concrete. Diffusion is the movement of a dissolved substance under a concentration gradient. That is, ions in solution […]