Concrete Casting News from the Hill and Griffith Company

Paul writes:

What factors could cause bugholes? How does aggregate gradation affect bugholes?

NPCA Technical Services engineers answered:

There are many different variables that could affect the surface finish of hardened concrete and cause bugholes. For conventional wet-cast concrete, the consensus is that the primary culprit is improper vibration, but that’s true even with self-consolidating concrete. The rapid placement of SCC could lead to entrapped air and, if procedures to remove the air aren’t in place, bugholes could form. 

Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

Designing a buried pipe? Be sure to avoid these common—and potentially costly—mistakes.

The design of buried pipe encompasses many of the basic civil engineering concepts we learned in college: hydraulics, soils engineering, and structural engineering. Yet, I’m willing to bet most of us didn't take a class specifically dealing with the design of buried pipe. Thus, it's easy to miss some of the finer nuances when designing buried pipe. Here are some areas where we have seen issues throughout our years in the industry. 

Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

The American Concrete Pipe Association's PPT, "Pre & Post Pour Inspections" contains information on Documentation, Pre-Pour Inspection of Equipment & Reinforcement, and Post-Pour Inspection of Stripping, Handling, Visual & Dimensions 

This is an excellent presentation of all the steps involved in producing high-quality concrete pipe. 


Go to this link to download the PowerPoint.

Download a PDF.

Concrete Pipe Manufacturing Pre-Pour Inspection - Form Release: Application methods, brush, spray; How much is enough??, Too Little, Too Much, Affects concrete finish, may affect curing

Concrete Pipe Manufacturing Pre-Pour Inspection - Form Release: Barrier (non-reactive); Examples, Petroleum-based diesel, heating oils, used crankcase oil;

Advantages, Creates a physical barrier between form and fresh concrete;

Disadvantages, Need heavy application for easy release (200-400 ft2/gal), Can cause staining and bugholes, May not meet VOC requirements, Can cause buildup on forms

Concrete Pipe Manufacturing Pre-Pour Inspection - Form Release: Chemically Reactive; Examples, Fatty acids (vegetable and mineral oils) are chemically reactive agents that combine with calcium in fresh cement paste to produce a soap-like film between the concrete and the form;

Advantages, Prevents bonding of concrete to form, Ultra-thin Layer (Approximately 0.005”), Reduce bugholes, stains, dusting, Typically meets VOC requirements (verify)

Disadvantages, Typically more costly per gallon

Concrete Pipe Manufacturing Pre-Pour Inspection - Seasoning

1. Remove protective coating to prevent staining, sticking, poor finish

• Wear off during production
• Solvents
• Grind
• Blast

2. Apply high fatty acid concentrate release agent; Let it react (forms metallic soap barrier). If using a barrier agent, use it for seasoning.

3. Ideally allow 24-hr sit-time

4. Apply release agent

5. Put into use

The American Concrete Pipe Association was originally conceived in 1907 by a small group of concrete farm drain tile manufacturers as the Interstate Cement Tile Manufacturers Association in Ames, Iowa.

The group needed some means of exchanging ideas and establishing a high quality, standardized products. In 1914, the organization was renamed the American Concrete Pipe Association. Throughout the 20th century, the concrete pipe industry has experienced tremendous growth. As more and more people moved from farms to cities, it created increased demand for concrete sewer and drainage products. The introduction of the automobile and subsequent highway development extended the uses of concrete pipe storm drains and culverts. There are currently over 400 plants operated by ACPA members in the United States and Canada. Over 40 countries are represented in the membership of the American Concrete Pipe Association. ACPA’s international headquarters are located in Irving, Texas USA.

Precast Concrete Manufacturing Resources from the American Concrete Pipe Association

14 Reasons to Choose Concrete Pipe

Concrete Pipe Design Manual

Concrete Pipe Specifications

Hill and Griffith Customer Service

After more than 175 years, concrete pipe continues to be a product of choice for specifiers, contractors, and design engineers.

Throughout its 111-year history, the American Concrete Pipe Association and its members have met the demands of infrastructure owners while improving the quality and performance of concrete drainage and collection systems through advancements in product design, plant production, and concrete mixes. Contemporary de-signs of production plants in automated and robotic facilities ensure quality of products, health and safety, especially built to overcome severe weather conditions.

Article by Russell Tripp, P.E., President, American Concrete Pipe Association, USA, and published in CPI - Concrete Plant international May 2018. To read the entire article go to the introductory page at American Concrete Pipe Association's web site.

The U.S. has sustained 230 weather and climate disasters since 1980 where overall damages/costs reached or exceeded $1 billion (including Consumer Price Index adjustment to 2018). The total cost of these 230 events exceeded $1.5 trillion (www.ncdc.noaa.gov/billions). As of April 6, 2018, there have been 3 weather and climate disaster events with losses exceeding $1 billion each across the United States. [1]  The California wildfires, which burned more than 9.8 million acres in 2017, destroyed over 15,000 homes and businesses, caused 44 deaths, and racked up a cost of $18 billion. [2] 

Following disaster events, news reports documented pipeline systems and culverts that were irreparably damaged. Failed thermoplastic or corrugated metal drainage systems, from the wild fires in California to the hurricane damage in Texas and Florida, were identified as the primary cause of many road failures.

Unlike concrete, thermoplastic pipes will melt and burn. Based on recent fires in California, damage to a thermoplastic drainage system has extended far beyond the damaged pipe itself to include sidewalks, roadway, gas/oil pipelines, drinking water systems and nearby structures. Thermoplastic pipe materials installed close to the surface or where there is an ex-posed pipeline inlet or outlet run the risk of being damaged or destroyed by fire regardless of the use of special end treatments. Fires in concrete pipeline systems generally don’t affect structural strength or flow capacity; the two fundamental requirements of a gravity pipeline drainage or collection system. The repair or replacement of infrastructure is incredibly expensive, and the community impacts include the interruption of service, localize flooding and damaged roadways that severely disrupt traffic based on damaged thermoplastic or metal pipelines found in, or adjacent to road rights of way. Thermoplastic pipe culvert failures have been documented recently where access by emergency service vehicles were blocked resulting in loss of property and more threats to health and safety.

Before and after burn. Using the QR-Code you can see the ACPA Comparative Flammability Demonstration October 21, 2015 on www.youtube.com/watch?v=FoXuyWnaJm4

Concrete pipe production facilities produce one of the world’s most enduring products for storm drainage and sewage collection systems. The long-lasting performance of precast concrete pipe and box drainage systems is well documented in severe weather conditions. Compared to thermo-plastic drainage systems, concrete pipe has always been and will continue to be rigid, rugged, and resilient.

Russell Tripp, P.E., Clemson University alumnus, earned his Bachelor of Science degree in Civil Engineering in 1982. He spent the first 21 years of his professional career working in the natural gas industry. He then served three years in the PVC sheet pile industry and four years in the plastic drainage industry before joining the ACPA.

Precast Concrete Manufacturing Resources from the American Concrete Pipe Association

14 Reasons to Choose Concrete Pipe

Concrete Pipe Design Manual

Concrete Pipe Specifications

Hill and Griffith Customer Service

The American Concrete Pipe Association is the spokesperson for the concrete pipe industry in all matters affecting the industry’s welfare.

We researched their content and found some great free resources. Their home page section on "Pipe & Box Resources" starts off with Design and "14 Reasons to Choose Concrete."

"Concrete is the world’s most commonly used building material.

In its simplest form, concrete is a mixture of paste and aggregates. The material (paste) used to manufacture concrete pipe is composed principally of Portland cement and water, and is used to coat the surface of the fine and coarse aggregates. The Portland cement is a closely controlled chemical combination of calcium, silicon, aluminum, iron, and small amounts of other compounds, to which gypsum is added in the final grinding process to regulate the setting time of the concrete. Portland cement’s chemistry comes to life in the presence of water. Soon after the cement and water are combined, a chemical reaction called hydration occurs and the paste hardens and gains strength to form the rock-like mass known as concrete. During hydration, a node forms on the surface of each cement particle. The node grows and expands until it links up with nodes from other cement particles or adheres to adjacent aggregates. Within this process lies the key to the remarkable trait of concrete – it’s plastic and malleable when newly mixed and strong and durable when hardened. ..."

The 14th Reason is "Quality Control and Testing of Concrete Pipe."

Batching and mixing operations in the industry’s premier plants have been upgraded over the past 10 years. Characteristics of this operation of the pipe production process normally include:
• Computer controlled weighing and proportioning systems
• Computer controlled mixing systems
• Automated recording systems
• Absorption testing

The American Concrete Pipe Association offers an on-going quality assurance program called the “Quality Cast” Plant Certification Program. (http://www.concrete-pipe.org/qcast.htm). This 124-point audit-inspection program covers the inspection of materials, finished products and handling/storage procedures, as well as performance testing and quality control documentation. Plants are certified to provide storm sewer and culvert pipe or under a combined sanitary sewer, storm sewer, and culvert pipe program.

Line Item 6.1 "Forms shall be kept clean of concrete build-up and inspected after each use."

Line Item 8.2. "Pre-Pour Visual Inspection"
For each pipe produced, visually inspect the following applicable items prior to pouring:
• Reinforcing Placement
• Handling Holes / Lifting Devices
• Tie-pin Holes
• Release Agent Application
• Form Cleanliness and Condition
• Step Holes / Plugs 

Brief History of the ACPA

The American Concrete Pipe Association was originally conceived in 1907 by a small group of concrete farm drain tile manufacturers as the Interstate Cement Tile Manufacturers Association in Ames, Iowa. The group needed some means of exchanging ideas and establishing a high quality, standardized products. In 1914, the organization was renamed the American Concrete Pipe Association. Throughout the 20th century, the concrete pipe industry has experienced tremendous growth. As more and more people moved from farms to cities, it created increased demand for concrete sewer and drainage products. The introduction of the automobile and subsequent highway development extended the uses of concrete pipe storm drains and culverts. There are currently over 400 plants operated by ACPA members in the United States and Canada. Over 40 countries are represented in the membership of the American Concrete Pipe Association. ACPA’s international headquarters are located in Irving, Texas USA.

Precast Concrete News from the American Concrete Pipe Association

2018 Camp Fire — Reminder of Need for Fire-Resilient Infrastructure

Reinforced Concrete Pipe Replaces 20-Year Old Plastic System in Florida

Become a member of ACPA by completing a membership application

Hill and Griffith Customer Service