Haluhalo Reminds Me of Concrete
Haluhalo, simply translated as “mix-mix,” is a classic Filipino treat enjoyed not just during summer, but all year round. Markets, stalls, and malls serve various versions of this delicious, colorful, icy dessert that many crave. When you order a cup, the vendor begins by layering shaved ice with an assortment of local sweets—saba banana, langka (jackfruit), beans, macapuno (coconut sport), red munggo, nata de coco, sago (similar to tapioca pearls), and cubed gelatin—drizzling fresh milk on top. To make it special, instead of a typical cherry, they add a scoop of ice cream, a spoonful of ube halaya (purple yam), a chunk of leche flan, and a sprinkle of pinipig (toasted flattened rice).
This is exactly what I enjoyed on a sweltering afternoon in September. A literal mix of flavors and textures that cheered me up on that humid day and evoked happy childhood memories. In the coming together of this complex yet iconic dessert, I find a familiar essence of my favorite construction material—concrete! Just like haluhalo, choosing the right ingredients, the correct proportions, and mixing them just right is crucial for a satisfying outcome.
The Concoction
Every concrete mix is like a bowl of haluhalo. At its core is a mix design that creates the ideal recipe. Here’s a breakdown of the components that make up concrete:
| Sweet fillers | Aggregates
The sweet fillers are the stars of the show, giving haluhalo its character, volume, and bursts of flavor. In concrete, aggregates—coarse and fine materials like gravel and sand—provide bulk and texture, making up 60% to 80% of the concrete mix. Without these ingredients, haluhalo would just be a bland, boring, and flavorless mush of crushed ice. |
| Crushed ice | Cement
Ice binds everything in the mix, blending the elements into one refreshing treat. In concrete, cement acts as the binder that holds the mix together in a unified matrix. While ice melts with the haluhalo ingredients, cement in concrete undergoes hydration—a process that makes the concrete hard and firm. |
| Milk | Water
Milk makes haluhalo an irresistibly creamy and silky summer indulgence. Have you noticed how pouring too much makes it watery, but using too little makes it hard to mix? In concrete, water is not only important for the hydration process; the right amount of water also impacts the strength and workability of the mix. |
| Toppings | Admixtures
Toppings are optional, allowing you to customize your haluhalo to enhance its flavor. In concrete, this is similar to using admixtures, which enhance the concrete’s properties. Admixtures can make concrete set faster or slower, increase workability, improve durability, or reduce its natural shrinkage. And of course, just like a special haluhalo, the type and amount of admixture can increase the overall cost of the mix. |
Oops… I think we forgot something.
Whenever my haluhalo is served, I immediately dig in to enjoy it without giving much thought to how the air bubbles form when I mix it. I mean… who would? The air between the crushed ice keeps my haluhalo fluffy and light. In concrete, air may not be a visible component, but it is critical to its performance, especially when exposed to freezing and thawing. Air spaces allow the ingredients to flow evenly through a spoon (or shovel!) during the mixing process!
The ACI way of haluhalo
Much like following a recipe, ACI 211 provides a standard mix design procedure that involves eight basic steps:
- Choice of slump
- Maximum aggregate size selection
- Mixing water and air content selection
- Water-cement ratio
- Cement content
- Coarse aggregate content
- Fine aggregate content
- Adjustments for aggregate moisture
Each step is like adding a layer to our haluhalo, carefully measured to achieve the perfect balance.
Scooping the right proportion and mixing it right
The selection of ingredients for haluhalo is like finding the right proportions for a concrete mix. Any adjustment requires a change in other components, so making the mix isn’t easy. For instance, adding more milk requires more ice to balance the flavor. Concrete mix design is similar; keeping the water-cement ratio within the accepted range is essential to control the mechanical properties of hardened concrete. Thus, getting the mix right is crucial for the durability and performance of a structure.
Now, have you ever heard of overmixing? Stirring too much or too little—including the mixing time, speed, and method—can influence the final quality of the mix. For haluhalo, overmixing can literally turn it into a mushy and soupy mess. Meanwhile, overmixing fresh concrete negatively impacts its quality by grinding aggregates into smaller pieces, increasing temperature, reducing slump, decreasing air entrainment, and ultimately weakening the strength of the concrete. This is particularly important because fresh concrete is a time-sensitive and perishable product. Proper testing plays a crucial role here. The tests for fresh concrete—slump, temperature, air content, and density—help monitor for overmixed concrete. Learn more about these tests in our previous article.
Mix-mix
What makes a good craft of haluhalo and concrete is the combination of what comprises it and how it’s done. The proportion and mixing process ensures a pleasing blend of the right ingredients that meets one’s preference or, technically speaking, the design specifications. Any deviation to design mix or method compromises its workability, durability, and overall performance of concrete, much like how haluhalo loses its appeal. By sticking to the right way of doing it, one can assure a well-prepared mix that delivers quality and satisfaction.
So, the next time or the first time you indulge in a delicious haluhalo, remember the science and art behind it and how similar it is to concrete. Both mixes require precision and creativity, one layer at a time.
