Steps to Prevent Concrete from Shrinking

We know that all concrete shrinks and that it is caused by a loss of volume that occurs in different stages of the process.  Shrinkage can affect the long-term strength and durability of the concrete as well as lead to cracking.  According to the Portland Cement Association, “The shortening of concrete slabs can be caused by temperature decreases or moisture loss. These two causes are also related to curling and warping of slabs, respectively. Curling is the deformation of the slab due to a difference in temperature between the surface and the bottom of the slab (temperature gradient).  Slab “warping” is the deformation of the slab surface profile due to a difference in moisture between the surface and bottom of the slab (moisture gradient).”  

Even though we understand what causes shrinkage, it is still a challenge to prevent or alleviate it.  It is especially important to control it in concrete floors as the subsequent cracking will affect the performance of the floor.  This is why when Conco broke the world record for the largest continuous mat pour on the Wilshire Grand in L.A., we worked to carefully monitor the thermal characteristics of the pour to prevent cracking. 

One of the first things we addressed was to increase the proportion of fly-ash in the concrete mix design, which normally results in reduced maximum temperatures.  The next step was to mechanically control the temperatures, and for a project of that size, pre-chilling was not an option.  What we did was to post-chill the concrete by means of cooling pipes that mechanically removed the heat.

For this undertaking, we teamed up with several companies that helped to design and implement a thermal control plan specific to the mix design, the geometry of the foundation, and the configuration of the rebar.  In the end, the system we installed to post-chill the concrete was composed of 18 miles of cooling pipes, over 660 tons of chiller capacity, 40,000 gallons of chilled water, multiple pumps, 3 x 500kva of generators, and over 2,200 valves.  By keeping temperatures well below the ACI limits, we were able to avoid thermal cracking.

Sources:

http://www.cement.org/for-concrete-books-learning/concrete-technology/focus-on-floors/concrete-shrinkage

Our mission is to be the best supplier of concrete services in the Western U.S. and to bring experience, expertise and quality to each project. We continue to upgrade and expand facilities to better serve the growing market for a wide range of construction development.  The Conco Companies have regional offices serving Northern California, Southern California, Washington State, Oregon, Colorado and Nevada.

Blended Cements Extend the Life Span of Concrete

Concrete mixes made of portland cement are porous and are susceptible to cracking especially during freeze/thaw cycles.  They can even be the cause of deterioration of rebar as moisture may seep in over time.  To reduce concrete’s permeability to water and prolong its life span, blended cements are used and offer an advantage of reducing the water-cement ratio (w/c), which one method of producing high-strength concrete. 

Blended cement as defined by the American Concrete Institute’s (ACI) Cement and Concrete Terminology is “hydraulic cement that is produced by intergrinding portland cement clinker with the other materials or by blending portland cement with the other materials or a combination of intergrinding and blending.”  Changes were made to blended cements in 2012 for special applications as well as for general use that have the approval of the ASTM.  

The ASTM’s C595 abstract on hydraulic blended cements describes “Type IS” as Portland Blast-furnace Slag cement and “Type IP” as Portland-pozzolan cement.  The C595 abstract states that, “They can also be described according to air-entraining, moderate sulfate resistance, moderate heat of hydration, high sulfate resistance, or low heat of hydration properties.”  Type I (SM) Slag-modified Portland cement has a standard that contains less than 25% slag by mass of the cement.  With the ASTM’s C595 change, it now permits Type IS Portland Blast-furnace Slag cement to contain between 25 and 70% by mass of the finished cement. 

 

By varying the proportions of the mix, blended cements are customized and produced to meet the demands of specific projects.  Furthermore, the ASTM goes on to say that, “cement shall undergo different tests to determine the following properties: chemical analysis, fineness by sieving, fineness by air-permeability, autoclave expansion, time of setting, air content of mortar, compressive strength, heat of hydration, normal consistency, specific gravity, water requirement, mortar expansions of blended cement and pozzolan, drying shrinkage, activity index with Portland cement, and sulfate resistance.”

At The Conco Companies, our mission is to be the best supplier of concrete services in the Western U.S. and to bring experience, expertise and quality to each project. We continue to upgrade and expand facilities to better serve the growing market for a wide range of construction development.

Conco’s Founder, Matt Gonsalves

The Conco Companies were founded in 1959 by Matt Gonsalves, Gerald Santucci, Ray Santucci, Will Gonsalves, and Mel Gonsalves.  Matt Gonsalves has held the position of President and is still active in the company serving as the Chairman of the Board.

The business got its start by pouring patios and driveways in Contra Costa and Alameda Counties.  Today Conco is one of the largest commercial concrete construction companies in the Western U.S. operating in California, Oregon, Washington, Nevada, and Colorado. 

The highlights of Conco’s longevity in the industry include providing premium concrete services for many of the most distinguished projects on the West Coast throughout the decades.  Some of the more prominent projects include the Pacific Bell Park, San Francisco Giants Stadium, the retrofit of Los Angles City Hall, Nokia Theater L.A. LIVE and Parking Structure, UCSF Neurosciences Lab and Research Center, Seattle Seahawk Parking Garage, Millbrae and Concord/Martinez BART Stations, and the Marriott Hotel in San Francisco. Recently we have been involved in the San Francisco 49ers Levi’s Stadium, the Bay Bridge Repair, the Wilshire Grand in L.A., and currently the Salesforce Tower in S.F.

As an innovator and inventor, Matt Gonsalves is credited with pioneering the use of 10” to 12” MAT slabs to create slab foundations that are not as prone to cracking or bending with earth movements.  He also invented the Waffle-Mat System, which is the process of pouring concrete over plastic molds to create a waffle-type mat effective on expansive soils. 

He also initiated the formation of the Concrete Contractors Association and has served as the President of the Building Industry of America (BIA).  Furthermore Mr. Gonsalves assisted the California Contractors State Licensing Board in developing test questions for its contractor license exam and working with political representatives to make changes to the cash retention policies in the construction industry.  Many of his ideas on various concrete methodologies have become today’s standards and practices.  In 2000, he was inducted into the CBIF Hall of Fame.   

Conco’s mission is to be the best supplier of concrete services in the Western U.S. and to bring experience, expertise and quality to each project. We continue to upgrade and expand facilities to better serve the growing market for a wide range of construction development.

Conco’s Reliable Trucking Company

 

In the Conco Companies’ quest to offer customers the best value in concrete construction services, we also own and operate the Reliable Trucking Company.  Just as the name suggests, the trucking company is known for safe, dependable construction hauling. 

Our fleet is fully CARB compliant (the legislation that mandates reductions in diesel emissions for all trucks in CA.) and we bring the same professionalism to our trucking services as to the rest of our Conco services.  Our modern fleet consists of pneumatic tankers, bottom dumps, semi-end dumps, ten wheelers, transfers and flat beds capable of hauling cement, aggregates and construction materials.

 

Reliable drivers are chosen carefully as with any of our Conco employees and commercial vehicle drivers must possess a Commercial Driver’s License (CDL).  In addition fleet operations must be performed in accordance with all state and federal regulations including but not limited to the Department of Transportation (DOT) and the Department of Motor Vehicles (DMV).  Our company’s Fleet Safety Program focuses on driver courtesy, regulatory compliance and accident prevention thru weekly training, quarterly safety meetings and management compliance audits. 

Currently Reliable is looking for truck drivers across their California locations for local deliveries only.  For Bulk Pneumatic Drivers, we have openings in Redwood City, Martinez, Stockton, and Woodland.  Applicants must possess a Class A license with doubles/triples and tank endorsements.  Experience with pneumatic trailers is preferred but not necessary. 

For Bottom Dump Drivers, openings are in Redwood City and Martinez.  Candidates must possess a Class A license with doubles/triples endorsement.  Experience with bottom dump trailers is preferred but not necessary.  Both of these jobs offer competitive wages along with medical and retirement benefits.  A clean DMV and no failed drug tests are also a must.  Please see our website for all of the details and contact info. 

As one of the top commercial concrete contractors in the Western U.S. since 1959, we understand the importance of building materials to be delivered safely and in a timely manner.  We work hard to provide our customers, employees, and the general public with the safest, most efficient trucking services in the industry. 

 

Conco is an leading supplier of commercial concrete services for the Western United States.  Our extensive services include commercial, educational, parking and other construction development as well as public works projects and highways.  We have four regional offices serving California, Oregon, Washington, Nevada and Colorado. 

 

Another Way to Make Concrete Stronger

Mineral admixtures are an economical way to create even stronger concrete and provide an environmentally responsible way to recycle industrial and other waste by-products.  In addition while chemical admixtures only make up about 5% of the concrete mass, mineral admixtures can be used in large amounts to replace portland cement and/or fine aggregates. 

So what are mineral admixtures?   Wikipedia states that mineral admixtures are “inorganic materials that also have pozzolanic or latent hydraulic properties. These very fine-grained materials are added to the concrete mix to improve the properties of concrete, or as a replacement for portland cement (blended cements).”  They are defined by the American Concrete Institute as “a siliceous or siliceous and aluminous material that in itself possesses little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically reacts with calcium hydroxide at ordinary temperatures to form compounds having cementitious properties.” 

The most common mineral admixtures are fly ash, silica fume, blast furnace slag, and metakaolin.  Fly ash is a by-product from coal plants and is used to replace up to 60% of portland cement.  Silica fume is a by-product of silicon and ferrosilicon alloys and has particle size 100 times smaller than fly ash.  Blast furnace slag is a by-product of steel production and can replace portland cement by up to 80% of the mass. 

So what are the advantages of using mineral admixtures?  According to the U.S. Department of Transportation, when mineral admixtures are added to concrete in larger amounts, “it enhances the workability of fresh concrete.”  DOT also states that it improves the resistance of concrete to thermal cracking, alkali-aggregate expansion, and sulfate attack as well as enables a reduction in cement content.

1.en.wikipedia.org/wiki/Concrete

2. concrete.org/TopicsinConcrete/TopicDetail.aspx?id=71&Search=Pozzolans

3. fhwa.dot.gov/infrastructure/materialsgrp/admixture.html

 

The Conco Companies mission is to be the best supplier of concrete services in the Western U.S. and to bring experience, expertise and quality to each project. We continue to upgrade and expand facilities to better serve the growing market for a wide range of construction development.

The Production of Cement in the US

 

According to the Portland Cement Association, “Nearly two-thirds of U.S. cement consumption occurs in the six months between May and October.”  They also say that around 70 percent of cement shipments are sent to ready-mix concrete operators.   The remaining cement is shipped to manufacturers, government entities, contractors and to oil well, mining, and drilling companies.  

The fine gray powder that is known as portland cement is the key component in concrete mixtures.  With more than 100 cement plants in the United States, our country has the capacity to produce over 100 million tons of cement a year, and we are one of the largest manufacturers in the world just behind China and India. 

The U.S. cement manufacturing plants are located in 36 states; however California, Texas, Pennsylvania, Florida, and Alabama produce about 48% of the cement manufactured in the U.S.  Many of the U.S. plants are owned by or are subsidiaries of foreign companies and almost 80% of our cement production comes from these companies.  

Most cement is transported by trucks as it is generally manufactured close to the site where it will be used as well as close to limestone quarries where the raw material comes from.  Furthermore, cement consumption is dependent upon favorable weather conditions, so in many places, it is a seasonal business.   

The production of cement reflects the state of the construction industry.  At those times when construction slows down, so does the demand for cement.  With the recent recovery in the economy and the subsequent uptick of many construction projects around the country, the cement industry is currently doing quite well.   

Source:

cement.org/for-concrete-books-learning/cement-manufacturing

The Conco Companies are a leading supplier of commercial concrete services for the Western United States.  Our extensive services include commercial, educational, parking and other construction development as well as public works projects and highways.  We have four regional offices serving California, Oregon, Washington, Nevada and Colorado. 

Intern Opportunities for Project Engineers

The Conco Companies are presently seeking interns and/or graduates for positions of Project Engineer.  We offer qualified candidates a chance to work with top professionals in the industry as well as with a company that has been or is involved in many of the most architecturally distinguished projects throughout the Western U.S.

Recently we have had the privilege to supply concrete services on projects such as the San Francisco 49ers Levi Stadium, the new Salesforce Tower in San Francisco and the Wilshire Grand in Los Angeles.  Our current posting for Project Engineers is from our Concord office and we will train the right candidates. 

The job responsibilities will include but are not limited to the following:

·         Handle required daily jobsite paperwork such as: Inspection requests, Safety reports, Pre-task paperwork, and Tailgate meetings. 

·         Manage Requests for Information (RFI’s) and handle “field condition” issues as they arise. Will need to learn the requirements for processing RFIs: Work with field personnel/General Contractor to identify best solutions to issues; Provide pictures/sketches/explanations to detailer; and Oversee field fix. 

·         Scheduling of Deliveries and Manpower: Attend jobsite scheduling meetings with Project Manager; Work with Project Manager adjusting delivery/crane/manpower schedules based on scheduling meetings; and Maintain and distribute schedules. 

·         Monitor and order/stock/track field/office use items: Gloves, glasses and vests, Harnesses, Oxy/Acet bottles, and Water 

·         Field support: Understand General Contractor’s schedule and how to achieve their goals; Work with and support our field personnel to achieve these goals; Quality control assistance; and Do a once per day safety walk.

Desired skills and experience include a strong familiarity with industry standards and knowledge of Microsoft Excel, Microsoft Word, PowerPoint and Adobe Acrobat Professional.  Please refer to our website for complete requirements and contact information. 

 

Conco is a leading supplier of commercial concrete services for the Western United States.  Our extensive services include commercial, educational, parking and other construction development as well as public works projects and highways.  We have four regional offices serving California, Oregon, Washington, Nevada and Colorado. 

Our New App

 

The Conco Companies are now offering a handy app that is available on your Android smartphone or tablet called the Conco Concrete Pumping Guide.  This free, easy-to-use guide provides our customers quick access to the entire list of our concrete pumps along with complete descriptions, diagrams, specifications and instructions for ordering. 

Our new app is organized by the geographic locations where the equipment is based and includes our sites in Northern California, Southern California and Washington State.  You just need to select the area closest to your location to see the full list of Conco’s state-of-the-art pumps available in your area.  To learn more about a particular pump, click on it, and it will take you to the detailed specifications and diagrams for that pump. 

If you are interested in having one of our professional operators and pumps out to your jobsite, the Conco Concrete Pumping Guide has a section on how to place an order.  Here you will find all of the necessary information including a phone number and comprehensive instructions for ordering a Conco pump for your project.  In order to best accommodate your pumping needs, we let you know the type of information we need.  This includes details regarding the particulars of the job as well as the characteristics of the jobsite where our pump will be used.  You will also find the terms of our operators’ work conditions. 

Conco has extensive experience in placing concrete and we offer a wide range of specialized placement options using our high-tech concrete pumps.  Our extensive fleet is equipped to move a variety of materials quickly and efficiently and will help your project save both time and labor cost.  For questions not answered on our Conco Concrete Pumping Guide, please contact one of our regional offices for further details. 

 

Conco is a leading supplier of commercial concrete services for the Western United States.  Our extensive services include commercial, educational, parking and other construction development as well as public works projects and highways.  We have four regional offices serving California, Oregon, Washington, Nevada and Colorado. 

Conco Offers Opportunities for Internships

The Conco Companies are currently seeking interns and/or graduates for the position of Concrete Estimators.  As one of the foremost commercial concrete contractors in the Western United States, this is an excellent opportunity for someone to have the chance to work with top professionals in the concrete industry. 

At Conco we have been in business since 1959 and have had the privilege to be a part of many of the most notable projects throughout the West.  Recently those have included the San Francisco 49ers Levi Stadium, the new Salesforce Tower in San Francisco and the Wilshire Grand in Los Angeles.  We have always been on the leading edge of industry advancements such as being the first company in the area to purchase long boom pumps that meet the latest emissions standards and help to reduce emissions at jobsites.

The Concrete Estimator position is with the East Bay Construction Company with satellite offices in Southern California and Seattle and we are willing to train someone.  Primary responsibilities include:  Preparing the project estimate, bid and schedule for commercial construction projects; Interpret plans and specifications, perform takeoffs and develop estimates; Evaluate subcontract, vendor and supplier quotes; Prepare RFI’s; and Oversee the budgeting and financing on a project.  Candidates will also need good communication skills, a strong desire to be part of the construction process and detailed oriented.  

Proficiency in Microsoft Excel and Word and Auto Cad are a plus as well as any previous experience in concrete estimating.  Prior employment or an internship with a construction company is also a plus.  Desirable skills include the ability to take an organized and systematic approach to monitoring and reviewing estimates, and familiarity with industry standards.  Please see our website for the complete details and contact information. 

Conco is a leading supplier of concrete services for the Western United States. We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products.  Since that time, we have taken a leading role as one of the top concrete contractors in the region. We have four regional offices serving California, Washington, Oregon, Nevada and Colorado.

World-class Commercial Concrete Contractors in the Reno Area

 

Looking for the best overall value for your next project? The Conco Companies have a team of highly professional commercial concrete contractors in Reno ready to help.  As a leading commercial concrete contractor in the Western U.S., we bring our fleet of state-of-the-art equipment and a team of skilled professionals to provide the growing market in the Reno area with premium concrete pumping services. 

With more than forty years in the industry, we have a proven record of handling the most difficult jobs regardless of their size and scope.  Our success lies in the fact that we work closely with each of our clients from the pre-construction phase right through to completion of a project.  Conco’s professional services include designing and executing innovative, cost-effective solutions to ensure your project meets timelines and stays on budget.   

Safety is our number 1 priority and the Conco team works diligently every day to provide our customers and the general public with the safest and most efficient construction and trucking services in the industry today.  To help us achieve this commitment, our concrete pump operators are ACPA certified as well as company specific safety trained. 

Additionally our boom pumps and Telebelts are inspected annually by certified boom pump inspectors to ensure the structural integrity of the equipment we operate. The Conco pumping division has an excellent safety record and we work hard to keep it that way.

We also offer a wide range of in-house services and resources to provide our customers the best value on a project.  Please see our website to learn more about our professional concrete pumping services in the Reno area. 

Conco’s mission is to be the best supplier of concrete services in the Western U.S. and to bring experience, expertise and quality to each project. We continue to upgrade and expand facilities to better serve the growing market for a wide range of construction development.

Building Trends that Address Disaster Mitigation

With over fifty years of experience as a leading commercial concrete contractor in the Western U.S., The Conco Companies have a portfolio that includes many innovative, exciting architectural projects.  We are always interested in learning more about the latest building trends, and as such, have started blogging about them.  Our latest addition involves disaster mitigation.  Some of the information is based on an article from the Chicago public media organization, WTTW, and discusses new building trends in the industry.       

We have all seen the damage that powerful EF4 and EF5 strength tornados have done in parts of Alabama, Missouri, and Oklahoma over the last few years.  The complete devastation of many of the single, wood-framed homes demonstrated how little protection they offered.  Not one of the wood-framed homes in the direct path of the forceful storms survived.   In addition we all saw the total devastation from hurricane Sandy that destroyed entire communities and left $71 billion in damages among the 24 states affected by the storm in 2012.

These types of disasters have been a call of action for communities, architects, builders and the government.  Organizations such as the American Institute of Architects (AIA) and the Federal Emergency Management Agency (FEMA) have joined forces to work on solutions to help mitigate this type of damage.  They are looking at better ways to prepare for future catastrophes and evaluate which areas are most at risk.  There is even talk about raising the standards of local building codes to help reduce or eliminate future damage.

According to WTTW, the recommendations from the group’s collaboration are “By retrofitting existing buildings, establishing more consistent building codes (and local standards suited to local risks), working through various “what if” scenarios, and putting plans in place for repairing and rebuilding when necessary, the architecture and building community hopes to improve readiness for – and response to – inevitable natural disasters.”

Source:

interactive.wttw.com/tenbuildings/ten-building-trends-could-change-america

When your project demands exceptional services and the best value, Conco can deliver. We partner with clients on every project from the pre-construction stage right through to final completion offering cost-effective solutions to meet the ever-changing demands of the industry. We have four regional offices serving California, Oregon, Washington, Nevada and Colorado. 

The New Trend in Modular and Prefab Structures

We bring you another post in our series regarding new and upcoming building trends with an article regarding “what’s old is new again.”  In this blog we will discuss a new way of rethinking the construction of yesterday’s modular and prefab structures.  Our information is based on an article from WTTW, a Chicago public media organization, on the latest trends in the building industry.

While in the past, modular or prefab structures had a poor reputation of being cheaply built and using shoddy materials.  Today there is a new way of thinking with the emerging trend of constructing high-quality, attractive modular buildings using sustainable, energy-efficient building materials.  In addition these environmentally-friendly structures have a reduced carbon footprint.  Since they are built in a factory rather than on-site, it eliminates the necessity of having to truck in all of the needed building materials.

Affordable homes, schools and commercial buildings are all being built as modular structures and are not only green but can be architecturally beautiful.  Even though they are factory-built, there is generally some room to customize the structure to get what you want.  Modular construction offers an efficient method of building with less material waste.  Furthermore, since they are built under controlled conditions (inside), there is the opportunity for more precision which means a higher quality, more durable product.  Typically buildings are constructed quicker than site-built structures and are less costly.   

The Conco Companies are one of the leading commercial concrete contractors in the Western U.S., and as such, we continue to be involved in many of the most innovative architectural projects being built in the area.  Large or small, many of the projects Conco supplies concrete services for have achieved LEED certification for their use of sustainable, energy efficient building materials.   

Source:

interactive.wttw.com/tenbuildings/ten-building-trends-could-change-america
motherearthnews.com/diy/modular-prefab-compact-green-homes-structures.aspx#axzz2M7oQm9J8

 

Conco is a leading supplier of concrete services for the Western United States. We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products.  Since that time, we have taken a leading role as one of the top concrete contractors in the region. We have four regional offices serving California, Washington, Oregon, Nevada and Colorado.