Wet Cast Vs. Dry Cast Comparison
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It’s a debate as old as the glaciers. The dinosaurs argued about it at their watering holes. Differing opinions on the subject sparked more than one open conflict. Do you actually believe the Anglo-Zanzibar War of 1896 was sparked by an exchange of power following the untimely death of a young sultan? Nope. Friendships have been severed. Families have splintered. Yet the debate rages on with no end in sight…
Dry cast concrete or wet cast concrete? Which precast concrete solution is better for your project?
Full disclosure: Redi-Rock blocks are proudly produced by our more than 150 global manufacturers using wet cast concrete. But we’re fair folks and this question deserves answers you can trust so we’ll explore the pros and cons of both dry cast and wet cast precast concrete to supply an objective and helpful comparison.
The Base Course
Short on time? Here are this article’s key takeaways…
Dry cast concrete mix is stiffer and more difficult to mold. Wet cast mix is more fluid and its higher water content makes it easier to form.
The industrial compression used to press dry cast mix into blocks and the resulting shorter curing time is a quicker process than the natural concrete curing period required of wet cast blocks.
Both dry cast and wet cast blocks can be used in a variety of applications, though wet cast is a better choice for water projects and sites exposed to freeze-thaw cycles.
Wet cast’s more fluid mix allows for more detail to be transferred to the blocks during production.
Mix
Dry cast concrete mix features a low water-to-cement ratio, resulting in a blend featuring the consistency of thick mud or dough.
Wet cast concrete mix is achieved with a higher water-to-cement ratio, resulting in a more fluid mixture.
The Edge: Dry cast concrete has a lower water-to-cement ratio resulting in a stiffer mix, which can make it more challenging to blend and batch accurately. It’s not a big difference, but wet cast gets the nod for its higher degree of workability.
Production
Dry cast mix is placed in forms and compressed with high pressure to further densify the material and ensure proper consolidation. The products are subsequently allowed to cure in forms and are removed from the forms when hardened sufficiently.
Wet cast concrete mix is achieved with a high water-to-cement ratio, resulting in a more fluid mixture. The mix is poured into forms for curing and vibration is used to ensure a consistent mix and to avoid defects in the finished product. Upon curing, the products are stripped from their forms.
The Edge: Dry cast requires more heavy machinery and labor to produce compared to the wet cast process. Dry cast, however, cures much faster so it’s the winner of the production race because more blocks can be produced in a shorter time.
Application
Dry cast is commonly used for producing small retaining wall and garden wall blocks, patio pavers, pipes, manholes, and various structural elements.
Wet cast is used in precast products like large and small retaining wall and garden wall blocks, patio pavers and slabs, and various structural items.
The Edge: Dry cast and wet cast concrete can both be used in a variety of precast projects, competing directly in spaces like hardscape pavers, small retaining and garden wall blocks, and some structural elements. Both are equally versatile and it’s tough to say which of the two offers more solutions so we’ll call this one a tie.
Look
Dry cast’s compaction production process and stiffer mix consistency prevent detailed texturing of products. This leaves dry cast solutions with a somewhat one-dimensional appearance.
Wet cast produces more intricate, natural-looking patterns due to its more fluid composition which allows the mix to flow more easily into forms and molds during production.
The Edge: The deeper detail and more natural texture achieved with wet cast make it the clear winner when appearance matters. Those who prioritize the look of their projects appreciate the details only wet cast can deliver.
Durability
Dry cast concrete tends to have higher compressive strength and density than wet cast. The low water-to-cement ratio in dry cast produces a denser mix, resulting in strength and durability advantages.
Wet cast offers a lower porosity helping it perform better in regions that experience freeze-thaw cycles and marine scenarios, particularly salt water. Wet cast also holds up better when exposed to deicing salts.
The Edge: The choice here depends somewhat on the application you’re targeting and the environment in which you’re building. Dry cast and wet cast both offer sufficient overall strength that lends them to industrial and structural uses. Wet applications like flood walls or retention/detention ponds demand wet cast concrete’s lower porosity because dry cast’s higher porosity allows water to enter the blocks and expand when frozen, damaging the blocks and shortening their lifespan. The lower porosity of wet cast typically makes it the better choice in regions that experience regular freeze-thaw cycles.
The Bottom Line
When choosing the materials for your retaining wall, it’s easy to feel overwhelmed by the numerous considerations you’ll be confronted with. Avoid the temptation to home in on a single quality of dry cast or wet cast, instead evaluate them holistically against your project’s needs. For example, consider the lifetime value of your proposed wall. By “lifetime value” we mean the total you’ll spend on the wall’s design, purchase, installation, maintenance, and possibly, replacement should it reach the end of its design lifespan. Like many things in this world, we get what we pay for. Sometimes spending less for something that we don’t need to last is the wisest choice. We don’t spend a lot on work shirts, because if it rips or gets stained, we simply purchase another and don’t give it a second thought. But this spending philosophy shouldn’t apply to retaining walls. You’ll want to keep in mind that, should your wall require significant repair or even replacement, you’re not just buying the blocks. You’re paying again for design, engineering, and installation, on top of the blocks themselves. Overlooking the lifetime value of a retaining wall has led plenty of project owners to regret their decision to choose the cheaper option. For more information on lifetime value, visit the Redi-Rock pricing page.
So if you’re looking for a slam dunk recommendation here, you won’t get it. Both dry cast and wet cast have pros and cons and claim their space in the construction industry. Your choice should be predicated on what’s important to you.
Need a less expensive, small block retaining wall in a moderate climate that doesn’t need to impress with its appearance or last forever? Dry cast is your best bet. Looking for a large block retaining wall that needs to look great, handle water, stand up to the change of seasons, and probably outlive you? Wet cast is your best value.
Make the choice that works for your project, your site, your budget, and your style.
But in case you were wondering, T-Rex was a wet cast guy. 🦖