Tag Archives: portland cement

Pouring Concrete into Holes With a High Water Table

Back in my general contractor days we would run into building sites where water would fill up some or all of our hole depth. While this seemed highly problematic then it was actually far less of an issue than originally presumed.

Reader RACHEL in CLARK writes:

“We are looking to put up a 24′ X 32′ pole building in my backyard to be used as a garage/wood shop. We are located in a lower spot in town and have been told our water table is fairly high. I am wondering what type of foundation is going to be the best to use? (Floating Slab vs Sinking Poles vs Sinking Concrete Piers under a slab?). We are hoping to do most of the work ourselves.”

Embedded columns for post frame buildings are almost always both a best and least expensive design solution. Auger holes to depth and diameter indicated on your engineered building plans (always build from engineered plans). If water appears in your hole, it is not a problem, as you can pour concrete into water, professionals do it often. Order pre-mix concrete for your footings and bottom collars with a minimum amount of water content (a W/CM ratio of 0.33 would be ideal).

After about two hours your concrete will have transitioned from a plastic to solid state. Ground water will become your concrete’s friend as it will aid curing processes. Chemical reaction of hydration allows microscopic crystals of Portland cement to grow and interlock as sand and gravel together continues to happen for days, weeks and months after concrete has been poured and it needs water to complete this chemical reaction.

Provided you have available space, you may consider going to a 36 foot length – it takes no greater number of columns, trusses, girts or purlins and will reduce your investment per square foot.

Cement Versus Concrete

Cement versus Concrete

Scraping a chalkboard (also known as a blackboard) with fingernails produces a sound and feeling most people find extremely irritating. Basis of this innate reaction to sound has been studied in the field of psychoacoustics (branch of psychology concerned with perception of sound and its physiological effects).

mr owl tootsie roll popIn response to audio stimuli, a human mind’s way of interpreting sound can be translated through a regulatory process called Reticular Activating System. Located in the brain stem, the Reticular Activating System continually listens, even throughout delta-wave sleep, to determine importance of sounds in relation to waking cortex or rest of body from sleep. Chalkboard scraping, or noises illiciting an emotional response, have been known to trigger tendencies from the fight or flight response acting as the bodys primary self-defense mechanism.

Superman has his Kryptonite, mine happens to be misused construction terms. Here, in Middle America, I have gradually adapted to term “rafters” being used for roof trusses. My favorite chalkboard scrape happens to be with use of “cement” when the correct term would be “concrete”.

Although terms cement and concrete often are used interchangeably, cement is actually an ingredient of concrete. Concrete is a mixture of aggregates and paste. Aggregates are sand and gravel or crushed stone; paste is water and portland cement.

Cement comprises from 10 to 15 percent of concrete mix, by volume. Through a process called hydration, cement and water harden and bind aggregates into a rocklike mass. This hardening process continues for years meaning concrete gets stronger as it gets older.

Portland cement isn’t a brand name, but a generic term for a cement type used in virtually all concrete, just as stainless is a type of steel and sterling a type of silver. Therefore, there is no such thing as a cement sidewalk, or a cement mixer; proper terms are concrete sidewalk and concrete mixer. I rest my case.