Finding the Right Sand and Gravel Aggregates for Your Next Project
Sand and gravel deposits are natural raw materials found in river channels, seabeds, beaches, floodplains, and glacial deposits. Due to the wide abundance of these natural resources, sand and gravel have been part of the building blocks for civilization throughout history.
But aside from their profound influence on major infrastructures, sand and gravel are also popular for smaller home and landscaping projects. Naturally decorative, you can choose amongst various sand and gravel colours to match your landscape and outdoor home décor. And more importantly, you can choose various types based on their use and function.
The textures, sizes, and types of sand and gravel will determine the best performance for specific projects. Contact your local sand and gravel suppliers to help you decide which types are best for your home project needs. And consider their many types and uses.
Aggregate Types and Their Uses
Your sand and gravel suppliers source these aggregates from local stone quarries. However, these aggregates can also be sourced from pits, lakes, rivers, and seabeds.
Fine aggregates have small particles while coarse aggregates have particles larger than ¼ inch. And crushed aggregates comes from crushing large boulders, stones, rocks, and gravel from local stone quarries.
Sand is used almost everywhere. It is mostly quartz created by the weathering of igneous rocks, such as granite. Fine sand includes beach and utility sands. Beach sand contains fine, multi-coloured grains that are used to fill sandboxes in playgrounds, create beaches, and act as a base layer below patio stones.
Utility sand is used to fill in sandbags and trenches. It is also used to stabilize water, gas, and utility pipes.
Coarse sands are used in construction. Coarse sand is mixed with cement. And mason sand is mixed with mortar and concrete to lay stone, bricks, and blocks.
Bank-run sand can be fine or coarse and is mixed with concrete to set patios, pillars, and fence posts.
Sand is combined with water and other aggregates to create strong, durable concrete for a variety of uses. It is used as a binding agent in asphalt, and can also be used for decorative aggregate projects.
Also known as ballast aggregates, gravel suppliers source gravel aggregates from sifting quarried rock and crushing natural stone. There are two types of gravel aggregates:
- Scrabbled stone—can be natural, regular, or crushed.
- Gravel—round pebbles originating from river beds or sea beds. Small, rounded stones are also known as pea gravel and are used as decorative stone for gardens and landscaping.
Gravel aggregates are commonly used in concrete, foundations, road construction, and reinforced concrete.
Common uses for coarse gravel include gravel dog runs, patios, and driveways. Coarse gravel is also used along garden beds, around patio pavers, and for drainage.
Crushed stone typically comes from crushing the following types of rocks:
Granite—composed of feldspar, quartz, and mica crystals. This decorative stone comes in a variety of colours—pink, red, grey—and is used in high-grade concrete mixes. Riprap, large chunks of stone used along shorelines to prevent erosion, is often made from granite.
Limestone—crushed sedimentary rock. Along with granite and gravel, limestone is one of the most commonly used aggregates for reinforced concrete and road construction.
These aggregates are made by crushing construction waste—such as asphalt, bricks, and concrete. While cheaper than other aggregates, these secondary aggregates are not as strong.
But secondary aggregates do have a variety of uses, including:
- Reinforcing weak soils,
- Road construction,
- Maintenance jobs under asphalt and pavement, and
- Large-scale filler for 5- to 20-Mpa-strength concretes.
Ready-mixed concrete uses aggregates for about 80% of its composition. Sand and gravel are used in the creation of various concrete construction materials, such as concrete bricks, blocks, and pipes.
Aggregates make up the majority (about 95%) of asphalt. Along with paving roads, asphalt is used to create roofing and shingles.
Walkways can be made from all types of aggregates. However, if you want a walkway to comfortably walk on barefoot (e.g. from your pool to your house) consider using softer aggregates, like finer sand and smaller gravel that are ¼ inch or smaller in diameter, with a smooth texture and rounded edges.
Driveways can be made with crushed gravel and utility sand in a concrete mix, or gravel laid as is. When using gravel, it is recommended to layer gravel stones in three layers, with the largest on the bottom (3-4 inches in diameter), medium in the middle (2-3 inches in diameter), and crushed gravel on the top (3/8 inch in diameter).
Crushed base gravel or mason sand are commonly used under patio bricks and stones because these fine materials compact well and provide a secure base.
Gravel and sand are used as filler in paths, borders for flower gardens, walkways, and more. They are also available in a variety of sizes and colours to meet your landscaping needs.
House drain pipes, embankments, and the bottom of hills are common areas for soil erosion. Gravel and sand are used to prevent soil erosion in landscapes. By filling the eroding areas with gravel, utility, or fill sand, the soil will become compacted, sturdy, and secure.
Flowerbeds and Trees
Gravel is a good alternative to mulch for gardening because it is sturdy and it prevents water from evaporating from the soil, especially on hot sunny days. Although smooth gravel is more decorative, rough gravel is more stable. Try all-purpose gravel, 3/8 inch in diameter.
Rock gardens can use any sand or size of gravel stones. Smooth gravel, especially river rock, will look especially nice in a rock garden.
For proper drainage for flowers, place gravel in the soil at the bottom of flower pots. Homes without gutters can use drip edges made from crushed stone to prevent mud from splashing up onto the side of the house when there is stormwater runoff.
Crushed stone is also used for drainage behind retaining walls—¾ inch is most common, but you can also use 1 ½ inch. Crushed granite is another popular choice, especially for drip edges, because of its nice appearance.
Icy Roads & Walkways
Sand and gravel are also used as a safety measure on icy roads, railroads, sidewalks, driveways, and walkways. These aggregates provide traction to prevent slips, falls, and skidding on ice throughout the winter.
Sand and gravel are used as filtration beds at water treatment plants. And sand is a common filtration ingredient in pool filters.
Sand is also used in sandblasting, and to build golf courses, volleyball courts, and equestrian arenas.
Why Sand and Gravel Are So Important in Construction
Sand and gravel are essential for concrete construction. These aggregates are used in a wide range of construction projects, literally making up the building blocks for our cities. Sand and gravel are key ingredients in cement, mortar, plaster, concrete, and blocks.
These aggregates are used to build foundations for homes, schools, hospitals, and buildings of all sizes. They are also widely used to build roads, highways, bridges, skyscrapers, sidewalks, parking lots, and bike trails.
Here are some of the major uses for sand and gravel in construction.
Ready Mixed Concrete
Aggregates used in ready mixed concrete directly affect the concrete’s fresh and hardened properties. Aggregate properties like the following are carefully considered when mixing concrete.
- Particle shape and size
- Surface texture
- Surface moisture
- Skid resistance
- Surface moisture
The type of aggregates selected for ready mixed concrete must produce consistent concrete strength, durability, workability, and finishability.
Sand and gravel are often used with soil to fill holes and elevate the ground on construction sites. These are also used to build shoulders next to highways.
When building roads and driveways, sand and gravel are used as a base—bottom layer. This base stabilizes the road and helps distribute weight more evenly, so it can support the heavy weight of cars and trucks.
Railroad ballast consists of a bed of crushed rocks below and along the sides of the tracks. Often made from crushed granite, and sometimes crushed limestone, railroad ballast helps stabilize and secure railroad tracks.
When planning your next home project, consider the versatility of sand and gravel. These aggregates are valuable natural resources with so many uses, it’s no wonder they’ve been part of the building blocks of civilization for so long.