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Materials and Proportions used in Concrete Masonry Units

Identifying materials used in production of Concrete Masonry Units (CMU) and the properties they have that make them suitable for use in production. 

Materials used in Concrete Masonry Units

Materials used to produce CMU are composed of cementitious materials (10-15%), water(5-10%), admixtures(>1%) and aggregates(75-85%). 

  • Normal Weight Aggregates - [ASTM C33]
    • Natural - Sand, Gravel, Crushed Limestone
    • Manufactured - Blast/Steel Furnace Slag, Recycled Concrete
  • Light Weight Aggregates - [ASTM 331]
    • Natural - Pumice, Scoria
    • Manufactured - Expanded Clay, Shale Slate

Proportioning of Materials

Proportioning of materials in the mix for CMU is an important stop in producing high quality units. A well proportioned mix can affect a unit's physical properties (compressive strength, unit weight, absorption, durability, appearance, linear shrinkage)  so they meet or exceed ASTM C 90 Standard Specification for Load-Bearing Concrete Masonry Units. The most commonly used method to determine the proper proportions is called Fineness Modulus Method (FM Method). The coarser the aggregate, the higher the FM. Knowing the FMs of your aggregates is crucial to calculating the proper proportions when producing CMU. Aggregate blends shouldn't contain excess fines or coarse particles. An excess in fines will lead the mix to require more cement and an excess of coarse aggregate with contain larger interconnecting voids. This is why calculating the right proportions and using quality aggregates is essential in producing a quality CMU. 

Posted on Sep 10,2019

Intimidator Group Launches New Spartan Mower Facility

The Intimidator Group in Batesville, AR. recently completed a new 200,000 sq ft production facility for Spartan Mower. This facility features a variety of our products from Split-Face units in Graphite, Chiseled-Face units in a custom color and Burnished-Face units in a new color Midnight. The official opening of the building began late Spring 2019.

Posted on Aug 28,2019

What are Integral Water Repellents?

Integral water repellents are usually polymeric liquid admixtures incorporated into concrete masonry units during manufacturing to reduce the wicking characteristics of the units. As such, they make masonry materials water resistant by limiting the amount of water penetration through the block.

They are particularly beneficial for use in colored architectural concrete masonry units where post-applied finished such as paints and other weather-resistant materials are not desired.

They are also beneficial for the use in masonry that is intended to receive weather-resistant finishes, as they significantly limit any water that does manage to get into the cores of the block from migrating to the interior of the building by wicking. 

When used to mitigate water penetration, it is essential that integral water repellent admixtures be incorporated into the mortar at the jobsite, as well as into the block and any other masonry wall component to ensure adequate bond and similar reduced water wicking charateristics. A compatible water repellent admixture from the same manufacturer should be used in the mortar that was used in the block to ensure compatibility. 

While these admixtures can limit the amount of water that can pass through units and mortar, they have little impact on moisture entering through relatively large cracks and voids in the wall. Therefore, even with the incorporation, proper detailing to prevent water entry and quality workmanship to ensure filled and adequate mortar joints is still essential.

Any water that does penetrate past the external surface of masonry with integral water repellents is more likely to quickly drain to the base of the wall because the units are not prone to retain it. So proper flashing and weep holes are critical to divert any water that finds its way into the masonry back to the outside.


Posted on Aug 27,2019

The Pros and Cons of Block Masonry Walls

Concrete block is a very sturdy masonry material that is good for buildings and structures. Many large commercial facilities use concrete block walls as their main structural elements. They are also used in constructing smaller buildings like homes. Masonry walls, like many other materials, come with a list of pros and cons that contractors and architects should consider when making construction decisions.

The Pros 

A big advantage of using concrete block masonry walls is its durability. Concrete is one of the strongest materials available and is not susceptible to rotting, mold, or damage from various pests. Concrete is often fireproof and is often used a a firewall between rooms and other structures. Concrete with the help of an additive, such as Integral Water Repellent, can have a water resistant property which will fend off water penetration into your masonry wall. Another pro is its friendliness to the environment. Concrete masonry walls use recycled materials that don't contain harsh chemicals that will negatively affect your health or the health of the environment. The thickness of masonry walls acts as great insulation, reducing energy use and reducing the need for lumber. When choosing concrete masonry walls, you'll experience a decrease in construction time. 

The Cons

The first and most noticeable con of using concrete block masonry walls in the dullness of the appearance. This material is not the most visually attractive when comparing it to other building materials. The dry, gray color gives it an appearance that doesn't match up to the intrigue an natural beauty of other options. This con is something that can be changed with our Custom Concrete Masonry Units, which have enhanced features that display the natural beauty of concrete. These features include Brushed Face, Burnished Face, Brecciated Face, Chiseled Face, and Split Face. The second con is the cost. The cost on concrete masonry is generally more expensive than lumber. But that being said lumber and other building materials have their own set of pros and cons. Whether the additional cost will be worth it to your building project depends on the various details of the construction project at hand. 

In addition, the pros out weigh the cons with your only major con being the cost. But with a little more expense you are receiving a lot more durability and versatility, when it comes to using concrete masonry.


Posted on Aug 20,2019