What is Limestone and Why Do We Need It?

Limestone aggregate is a precious natural resource that is so basic to our daily lives it is often overlooked. 

It makes up about ten percent of all sedimentary rocks. Limestone is made up of calcite aragonite. A lot of limestone comes from skeletal fragments of marine organisms. Throughout history, many people have recognized limestone’s potential and used it for a building material. The great pyramids of Egypt, among many other landmarks, are constructed of limestone. It was also popular in the Middle Ages, due to its hardness, durability, and availability. 

Limestone can be crushed in various grades, making it perfect for varied applications. Whether you need a base course, filler, or landscaping material, this aggregate is extremely multi-purpose. Among its numerous uses: building material, an essential component of concrete, aggregate for the base of roads, as white pigment, or filler in products such as toothpaste or paints, as a soil conditioner, and as a popular decorative addition to rock gardens. It is also commonly used in everything from railroad ballast to flux stone for metal refining. Limestone formations contain about 30 percent of the world’s petroleum reservoirs.

Limestone could be the one rock that is used in more ways than any other. It is a vital aggregate to our society.

Construction Uses of Limestone

As the most widely used building material in the world, Limestone is used in the construction of roads, concrete, and other building materials. Crushed limestone is an essential ingredient in the products we take for granted to build our homes, schools, hospitals, offices and the roads we travel daily. 

Limestone is an important source of construction aggregate due to its strength, versatility, and low thermal expansion. It is used in concrete production (producing a stronger concrete less prone to expansion); used in asphalt production (hydrated lime reduces cracking and stripping); road construction (as a road base due to its strength and durability); new construction (in home construction under concrete slabs that form the foundation for homes); erosion control (as riprap along rivers, streams, drainage and road edges); and soil stabilization.


Hydrated lime from limestone has been used in hot mix asphalt (HMA) to reduce moisture sensitivity and stripping since the early 1900s in the United States. In addition to the chemical effects that lime imparts to reduce stripping potential and the aging impact resulting from oxidative hardening, the “filler effect” of lime improves resistance to high-temperature rutting and adds fracture toughness at low temperatures.

Concrete and Cement

People often use “concrete” and “cement” interchangeably, but a discussion about cement requires a distinction between the two. Cement is simply one of the ingredients of concrete, which is also made of sand and bits of gravel or crushed stone. Cements makes up between 10% to 15% of concrete’s total mass; though of course the exact proportions may vary from one mixture to the next, depending on the type of concrete is being made.

To make Portland cement—the most common type of cement—powdered limestone is heated in a rotary kiln. As a source of calcium, it joins with powdered clay to produce a product called clinker, which is then ground with a source of sulfate, like gypsum. It is mixed with water, sand and crushed rock to create concrete. The water, added through a process called hydration, starts the chemical reaction that causes the cement to harden and set, holding all of the ingredients together as concrete. 

Alternately, the cement can be mixed with just sand and water to create mortar, which is used to join bricks together.

Railroad Ballast 

Railroad Ballast, otherwise known as railway ballast is an aggregate commonly made from crushed limestone and other rock. Primarily utility and construction companies use railway ballast to provide a level base for rails and sleepers. Railroad ties, or sleepers, are the rectangular support piece kept perpendicular to the tracks. Ballast bears the load from the railroad ties and holds the track in place as the trains roll over it.  

Soil improvement

Calcium carbonate is one of the most cost-effective acid-neutralizing agents. When crushed to sand-size or smaller particles, limestone becomes an effective material known as Aglime, for treating acidic soils. It has been widely used on fields and small plots throughout the world for hundreds of years.

Farmers utilize the material to improve conditions for crop growing, homeowners can improve the appearance of their lawns with it and contractors may need to spread the material throughout the properties of newly constructed homes and businesses before sod can be laid down.

Landscape Stone

From winding garden pathways to spectacular fire pits, limestone aggregate is widely known to be an attractive and convenient stone for landscaping projects. Plus, since it’s low-cost, it is known as one of the highest value materials on the market.


Limestone (Calcium Carbonate) is one of the main components in glass manufacturing. Its’ main function is to introduce Calcium Oxide into glass recipe which is needed to improve chemical resistance and durability. It also acts as flux in glass manufacturing.


Many toothpaste manufacturers use limestone in their toothpaste. Most toothpaste is made up of roughly 50 percent abrasives. Being less hard than tooth enamel, Calcium carbonate serves as a mild-to-moderate abrasive. For this reason, it works well for cleaning and scrubbing teeth.

Shoreline Delivers

With over 35 years of experience, our team can bring our expertise to your next project. We are committed to ensuring our materials meet the highest quality standards with superior customer service. Contact us today to schedule your aggregate delivery.

*We do not deliver to residential customers.*

Shoreline Delivers

If you are looking for the right company that offers supply and transport for your construction business, contact Shoreline Aggregate today. Shoreline offers a wide selection of limestone, sand and gravel products for road construction, golf courses and sports field projects. We deliver aggregates throughout Illinois, Indiana and Michigan. Quarries are strategically located for quick delivery and competitive pricing.