Kirkpatrick Invests in Upgrades
to Guntersville Block Operation

Following two months of extensive upgrades, concrete block will now be made a lot faster
at Kirkpatrick Concrete’s Guntersville production facility.

Ricky Mead, general manager of Kirkpatrick’s northern division, says temporarily closing the company’s only block plant was somewhat painful for customers, but the resulting increase in efficiency will make the downtime worth it. “Here in our area, we're pretty strong with block,” says Mead. “A lot of schools go with block because they’re fire-resistant. Also, with us being in a storm area, you can also fill the cells in block and make them pretty resistant to tornado-type winds,” says Mead.

Manufacturer Columbia Machine, based in Vancouver, Washington assisted personnel with upgrades to the three-at-a-time block machine. “The machine is only about four or five years old, but these changes will really speed things up for us,” says Mead. Each cycle, the block machine can turn out three eight-inch concrete masonry units every six to eight seconds.

Tsali Burch, operations manager for the plant, says the modifications are already paying off. “Production is up,” says Burch. “We have the capacity now to produce four kiln a day, that’s about 10-thousand block in an eight to nine-hour day. For this plant, that is extraordinary,” he says.

The Guntersville operation is adjacent to the ready-mix plant and exclusively produces gray lightweight concrete masonry in a number of sizes. These units are lighter and easier for masons to handle. Block sales are made to residential and commercial customers in a 35-mile radius of the Marshall County facility.

“We value our block customers in Northeast Alabama,” says Mead. “It’s the cornerstone of building in this area because without a good foundation, you don’t have a good house. So, concrete and block, that’s what it’s all about,” he says. “I think over the next five to ten years this plant is going continue to do well.”

Latest Tech Topics:

Masonry Tech Topic:

Efflorescence

Efflorescence can be seen on mortar joints, concrete block faces, brick faces. A combination of conditions must be present for efflorescence to form: 1, there must be soluble salts in the masonry and 2, there must be moisture migration through the masonry, carrying the salts to the surface.
Masonry Tech Topic:

Leaking Walls

On so many complaints of leaking walls it is so apparent that the mortar is, in fact, the culprit. But it is the fact that not enough mortar has been put into the joints.
Masonry Tech Topic:

Mortar Types

Who would have thought that every other letter in the words ”mason work” were the origin for the letter designations assigned to the different types of mortar. In the 1950s’, these ”new” letter designations replaced the original mortar types of A-1, A-2, B, C, and D.

Hot Weather Masonry

Hot Weather Masonry Construction

BY DANIEL GREEN
I find it impossible to have a short conversation or to write a short technical article on hot weather masonry work and masonry mortar. It is too important a subject. Instead, as in the case with cold weather masonry work, I’ll hit the highlights and then provide a short list of readily accessible internet references.

Hot weather defined: “Normal” masonry construction is generally thought of as having ambient temperatures between 40 and 90 degrees F. The American Concrete Institute, ACI 530.1, considers hot weather conditions when the ambient temperature exceeds 100 degrees F or 90 degrees F with a wind velocity greater than 8 mph. Of course, there may be building codes and specifications that vary.

The Brick Industry Association, in their Tech Note 1 states, “The primary concern during hot weather is rapid evaporation and absorption of water from the mortar. ……without sufficient water, cement hydration slows or stops, which reduces the bond strength and extent of bond between brick and mortar”. Naturally compressive strength suffers as well. And, remember, the purpose of mortar is to bond the masonry units together.

In hot temperatures the mortar actually requires more water than at cooler temperatures to achieve a given workability or plasticity. Despite this increased initial water demand, the mortar may be more difficult to use and the board life and stiffening time is shortened. This is due to the increased water loss brought on by the higher temperatures of the masonry units, their associated higher absorption rates, and naturally, the higher evaporation rate into the air.

Significant problems that are brought on by hot temperatures include:

  • Surface drying of the mortar joint. Dehydration of the mortar joint leads to weak (lower strengths) and non-durable mortar. The resulting hardened mortar surface is prone to excessive weathering, higher absorption, and may present a “sandy” surface.
  • Rapid and excessive drying within the body of the mortar joint leads to lower durability of the mortar and as mentioned above, decreased bond between the mortar and the masonry unit.

Both scenarios can create non-durable and low quality mortar and can lead to reduced buckling strength of a wall that is concentrically loaded. It also reduces the wall strength under horizontal and wind loading.

Considerations for masonry work in hot weather:

  • Shade the materials and mixing equipment from direct sunlight.
  • Provide conditions that will produce mortar below 120 degrees F.
  • Keep the masonry sand in a damp loose condition.
  • Use cool mixing water. You can use ice to cool the mixing water but do not let ice be batched into the mixer.
  • Prior to batching mortar, rinse the mixer with cool water.
  • Cool the transport container (wheel barrow) and the mortar boards and tools with cool water.
  • Retemper the mortar using cool water.
  • Use mortar within 2 hours if initial mixing
For additional information and references:

Read more

Mortar Types

Mortar Types & MaSoN wOrK

BY DANIEL GREEN
Who would have thought that every other letter in the words ”mason work” were the origin for the letter designations assigned to the different types of mortar. In the 1950s’, these ”new” letter designations replaced the original mortar types of A-1, A-2, B, C, and D. It seemed that A-1 carried a connotation of “best”, A-2 being 2nd best, and so on down to D. Naturally, this is not the case, as each type of mortar is intended for a specific use and no single type of mortar should be perceived as “best” for all purposes. With that, our MaSoN wOrK designations were created.
ASTM C270, Standard Specification for Unit Masonry, now includes only four types of mortar: M, S, N, and O. Type K is no longer specified. Choosing the mortar type: No single type of mortar is suited for all applications. The architect or engineer should specify the mortar that best meets project requirements. A good rule of thumb is to use the mortar with the lowest compressive strength required for the masonry feature.

Type M mortar is a high strength mix of at least 2500 psi that offers greater durability than other mortars. Use it for both reinforced and unreinforced masonry that may be subject to high compressive loads, severe frost action, or high lateral loads from earth pressures, hurricane winds, or earthquakes. Type M may be used in structures below grade and in contact with soil, such as in foundations, retaining walls, walks, sewers, and manholes. To produce Type M mortar, combine one bag of Coosa Portland Cement and one bag of Coosa Light Type N Masonry Cement (see Type N description below) along with 4 ½ to 6 cubic feet of damp, loose, masonry sand. *

  • Type M

    Type M mortar is a high strength mix of at least 2500 psi that offers greater durability than other mortars. Use it for both reinforced and unreinforced masonry that may be subject to high compressive loads, severe frost action, or high lateral loads from earth pressures, hurricane winds, or earthquakes. Type M may be used in structures below grade and in contact with soil, such as in foundations, retaining walls, walks, sewers, and manholes. To produce Type M mortar, combine one bag of Coosa Portland Cement and one bag of Coosa Light Type N Masonry Cement (see Type N description below) along with 4 ½ to 6 cubic feet of damp, loose, masonry sand. *
  • Type S

    Type S mortar achieves high tensile bond strength and compressive strength of at least 1800 psi. Use Coosa High Strength Type S Masonry Cement for structures subject to normal compressive loads, but that require high flexural bond strength. Also, use Type S where mortar is the sole bonding agent between facing and backing, such as adhesion-type, terra-cotta/stone veneers. To make Type S mortar, use one bag of Coosa High Strength Type S Masonry Cement with 2 ¼ to 3 cubic feet of damp, loose, masonry sand.*
  • Type N

    Type N mortar is a general purpose mortar for use in above-grade masonry structures. It is well suited for masonry veneers and interior walls and partitions. Type N mortars accept a wide range of pigments for custom color applications. This medium strength mortar, which achieves a minimum of 750 psi provides excellent workability and board life. Use one bag of Coosa Light Masonry Cement with 2 ¼ to 3 cubic feet of damp, loose, masonry sand.*

Type O

Type O mortar is a high lime, low strength mortar, achieving 350 psi minimum. It is primarily recommended for tuck-pointing and similar repair work. Its’ exterior use is limited because of its’ low structural limitations. It is not recommended for areas of high winds.

When preparing Type O mortar, combine 1 bag of Coosa Portland Cement and 1 ¼ to 2 ½ cubic feet of Type S hydrated lime along with 2 1/4 to 3 times the sum of the separate volumes of cementitious materials of damp, loose, masonry sand.* Mix all of the solid materials and then add sufficient water to produce a damp mix that will retain its shape when pressed into a ball by hand. Mix time is 3 to 7 minutes, preferably with a mechanical mixer. Let the mortar stand for 1 to 1 ½ hours for pre-hydration. Add sufficient water to bring the mortar to the proper consistency for tuck-pointing, which is somewhat drier than for laying the units.

Type K

Type K mortar has not been a part of ASTM C270 for many years. Sometimes it may be specified for restoration of historic or “ancient” buildings or structures that require a mix that is not significantly stronger than the surrounding masonry work. Type K mortar compressive strength is about 75 psi. *Use masonry sand conforming to ASTM C144, Aggregates for Masonry Mortar. Add sufficient water to obtain desired mortar consistency. Mix 3-5 minutes after all of the ingredients are in the mixer. Workmanship, unit suction, mixing, curing and other variables affect the overall masonry quality.

Finally, and perhaps needless to say, this article merely touches on the highlights of mortar type selection, proportioning, and mixing. For additional information, and to name only a few, I’ll offer additional reference sources:

For additional information and references:
Download:

Download PDF

Read more

Leaking Masonry Walls / Leaking Mortar Joints

Leaking Masonry Walls / Leaking Mortar Joints

BY DANIEL GREEN
About a quarter century ago, Mr. C.T. Grimm, PE, whom I wish I could have met, published my favorite masonry article, “Masonry Problem Goes Unsolved for 100 Years”. The article discusses a masonry issue that has plagued our industry, perhaps first documented in the late 1800s: Unfilled mortar joints.

On so many complaints of leaking walls it is so apparent that the mortar is, in fact, the culprit. But it is the fact that not enough mortar has been put into the joints.

Bed joints for brick walls: these joints must be spread uniformly thick. Furrowing must be kept to a minimum, if performed at all, as some building codes prohibit furrowing. As the bricks are put/shoved into place, their weight and the weight of the coursed above will help to compact the mortar and help promote a water resistant joint. These efforts will provide a “void free” joint, not allowing collection areas for water that could cause areas of freeze damage or embedment corrosion.

Head Joints for brick walls: These joints seem to be more susceptible to water leakage than bed joints. Needless to say, if they are not filled full, (full head joint) there will be mortar void areas which provide channels for water to run to the inside face of the wall / building.

During one of my early on, leaking wall inspections, I was led to the attic space of a new house. The builder had already torn off the styrofoam sheething exposing the interior face of the brick. The wall certainly was leaking, as there were kitchen baking pans on the attic floor to catch the water. Interestingly enough, I could see daylight coming through several head-joint areas. I figured if the light could come through, so could the rainwater. Again, it was a mortar problem…not enough of it.

A classic, typical example of a non-full brick head joint can be seen below. Figure 1 shows the mason applying mortar to the head of the brick. Figure 2 shows the “as-installed” brick and joint. I call this a “clip-joint” where only the outer ½” - ¾” or so of the brick receives mortar. The cosmetic appearance of the finished wall looks good. But there are hidden problems. When it comes time for the mason to run his jointing tool on the joint, instead of the compacting and densifying action that is supposed to be accomplished, the mortar in the clip-joint can actually be pushed back, breaking the initial bond that had formed between the brick and mortar….a perfect beginning for a leak. Remember, the function of mortar is to bond all of the bricks together for strength and water tightness.

  • Figure 1: The mason applying mortar to the head of the brick.
  • Figure 2. These joints look acceptable from the outside, but it is a typical “clip-joint” or non-full mortar head joint. A potential leakage area.
  • Figure 3. full head and bed joints
Figure 4: full bed and head joints at wall closure.

Bed joints for block walls:

The Portland Cement association discusses two types of mortar bedding: full and face shell.

Full bed mortar bedding: the webs, ends and face shells are bedded in mortar. This is usually used for the first or starter course on a footing. As a side note it can also be used for work where the wall is to be partially grouted.

Face shell bedding: it is common practice to use this type of bedding for all other hollow concrete masonry unit construction, where a full bed of mortar is applied onto the top of the face shell

Head joints for block: a full width of mortar is applied to the ends of the face shell. Some masons apply the mortar to the ends already in place while others stand the block vertically and apply the mortar to the end. Regardless of the procedure, a full width of mortar is required.

To conclude: use plenty of mortar in the joints and avoid mortar void areas. And remember, an important purpose of the jointing tool is to compact and densify the mortar joint, making it as water tight as possible.

Download PDF

Read more

Efflorescence

Efflorescence

BY DANIEL GREEN
The Portland Cement Association (PCA), in their Efflorescence Trowel Tips publication defines efflorescence as a crystalline deposit, usually white, that may develop on the surfaces of masonry construction.

Efflorescence can be seen on mortar joints, concrete block faces, brick faces. A combination of conditions must be present for efflorescence to form: 1, there must be soluble salts in the masonry and 2, there must be moisture migration through the masonry, carrying the salts to the surface.

On a more technical note; in masonry work, Portland cement is generally used in the manufacture of concrete block, mortar, and stucco. The cement, in the hydration process contains calcium hydroxide. Naturally, water is used to make mortar or block-fill. Moisture, migrating through the body of the feature carries this calcium hydroxide to the surface where it combines with the carbon dioxide in the air forming a new substance….the white powdery material, now calcium carbonate.

Actually, at this point this material is water soluble, so it is usually easily cleaned off during the masonry cleaning effort. If left alone, though, and if there is a continual problem with water migration or leakage from external sources, the efflorescence becomes carbonate deposits or lime runs. These can be quite stubborn to remove, requiring more aggressive cleaning efforts.

  • Figure 1. Efflorescence on dark charcoal mortar joints. You can see where the joints have been cleaned using water and a brush. The restored wall matches the color sample being held up to the joint.
  • Figure 2: Efflorescence on retaining wall. In contact with the soil, exposed to sprinkler system, no weep holes or flashing. Downspout continually saturates the ground.
  • Figure 3: Lime runs. This wall is not a retaining wall, but a “parapet” wall on one side of a handicap ramp at a doctor’s office. Rainwater running on the ramp saturates the masonry and migrates to this outside surface.
Figure 4: Brown manganese staining

The PCA further states that “All masonry and concrete materials are susceptible to efflorescence or staining. Interestingly enough, during periods of slow drying, and cool, damp conditions, such as in the winter, efflorescence can be more prevalent than in the summer.

Most efflorescence, especially on new construction, is temporary, very often called “new construction bloom”. It is most often removed during the masonry cleaning portion of the work. Recurring efflorescence indicates a chronic moisture or water flow problem such as from ground water in retaining walls, around un-caulked window openings, non-full mortar joints. Another source of “salts” can be where the masonry contacts the soil, such as basement and retaining walls. Also, some raw materials found in brick, for example, manganese, can cause brown stains.

There are a host of different types of staining that most refer to as efflorescence: In addition to the above:

  • White scum, Silicate deposits
  • Vanadium, green or yellow stains
  • Manganese, brown stains
  • Rust colored stains from embedments.
  • Organic stains, algae, mold, hard water from sprinkler systems.
  • Runoff stain from paint, copper.

Prevention

Prevention: to name a few:
  • Tool all mortar joints using a “v” or concave jointer. This provides the most weather resistant joint. Use full mortar joints.
  • Limit entry of water. Caulk around wall openings. Provide exit locations via flashing and weep holes. Maintain clean cavities and weep holes.
  • Cover the top course of masonry at the end of each day’s work, especially if rain is expected.
  • Do not clean masonry with unbuffered hydrochloric (muriatic) acid. (may cause yellow staining)
  • Carefully plan the positioning of lawn sprinkler heads so that walls are not subject to excessive wetting.
  • Keep masonry units at the construction site off the ground and covered.

Removal:

  • Avoid the impulse to immediately clean off efflorescence on new construction, especially in cool, damp weather. This usually forces more water into the wall making the condition worse. Give the masonry time to dry. It very well may disappear by itself, or may just require a light cleaning.
  • Use propriety cleaning agents if necessary, starting with a mildly diluted solution of 1 to 10 %. Always check with the brick manufacturer for his recommendation. For colored concrete masonry units or colored mortar, use only 1-2% solution. Always presoak the masonry with water so the cleaning solution will work on the surface and not be drawn into the masonry.
  • It is important to determine the type of salt in the efflorescence so the appropriate cleaner can be used.
  • Always treat a test area prior to the entire work.
  • In cases of recurring efflorescence, the source of the moisture needs to be determined and corrected.

Side Note:

On a side note: I’m reminded of a conversation with probably the most knowledgeable, architectural brick sales women I’ve ever met, from South Carolina. She told me that “efflorescence was (or could be) our friend”. I was surprised to hear her say that since it was such a complaint area. But she explained that if you have continued efflorescence then you have a water /moisture problem that may not be discovered until severe damage occurs. As I mentioned above, this can happen from excessive moisture in the building, leakage around windows or doorways, flashing or weep hole problems, leaking chimney caps, non-full joints, etc. She was right. Naturally, the migration of salts and the formation of efflorescence and its’ removal remedies can be a complex issue. Certainly more in-depth than can be addressed in this brief article. For additional information the following organizations, to name a few, have detailed, publish information.
For additional information and references:
Download:

Download PDF

Read more

Hodgson Concrete

  • Office: (334) 281-5141
  • Dispatch: (334) 281-0730
  • Fax: (334) 281-1911

Kirkpatrick Central

  • Office: (205) 423-2630
  • Dispatch: (205) 323-8394
  • Fax: (205) 423-2626

Kirkpatrick Northern

  • Office: (256) 582-3274
  • Dispatch: (256) 582-3274
  • Fax: (256) 582-3309

Walker Concrete

  • Office: (770) 506-7125
  • Dispatch: (770) 506-7125
  • Fax: (770) 507-9340
© Copyright 2019, ConcreteSouth.com
DBA: National Cement Company of Alabama, Inc.
A VICAT GROUP Company