Cetarc

Concrete in Hot weather - Part 1

In three decades of concrete manufacturing experience with leading ready-mix companies in United Arab Emirates, the most challenging time appeared to me was the summer season from June to September, every year. Production, delivery and placement of concrete was almost a “nightmare” in July and August.
The impact of hot summer on quality of concrete due to scorching temperature is huge and pose great challenges to the ready-mix concrete manufacturer and the contractor. Concrete starts behaving almost unpredictably with its rheology and setting properties. The quality control engineers get involved in trouble shooting of quality issues like loss of workability, temperature of concrete exceeding the maximum specified for concrete and development of early thermal cracks. The rejection of concrete due to quality issues are at peak during this season bringing up the heat on the professionals involved.
Contractors face problems in placing, compacting and final finishing of the concrete. Workability retention and consistency of the mix is very important to place and finish the concrete at site.
In middle east countries the peak ambient temperature easily cross 50oC mark during summer season leading to stoppage of concreting during day time. As per specified regulations, concreting is not allowed by consultants and local authorities in case the ambient temperature exceeds 40oC (though small &medium level contractors try to override this). In many occasions the night time temperature also exceed this limit leading to stoppage of concreting, hampering the progress of the project.
What are the specification limits for concrete temperature?
ACI specifies a limit of 35oC (ACI 305R, ACI 207.1R)
What is expected from a good quality concrete?
• Workability
• Consistency
• Strength
• Durability
Concrete shall be mouldable, placeable, strong, durable, resilient, sustainable, aesthetic, versatile
What is the impact of high temperature of concrete?
High differential between the internal temperature and the exterior temperature of a concrete mass, combined with imposition of constrains in expansion or contraction of concrete (restraint volume changes) will lead to cracks. High internal temperature against lower exterior ambient temperatures will cause cracking.
If temperature rise is not controlled, the later age strength of the concrete will come down from the expected normal results under standard curing conditions.
What are the factors influencing concrete during summer season and their impact on quality of concrete?
Hot sun, heavy wind, low humidity
How do we control concrete temperature?
• Use of flaked ice in concrete
• Replacing normal water with chilled water
• Shading of aggregates
• Dampening of aggregates before production of concrete
• Protecting the Transit mixer drums with dampened clothes
• Wind barriers and shades at site to prevent water loss
• Minimum time of haulage and placement of concrete from mixing of concrete at Plant
• Coarse aggregate can be cooled by passing frigid air through the bins or by passing the coarse aggregate through ice water
• Aggregate cool through vacuum processes (unless the moisture content of the aggregate is quite uniform, don’t apply this process)
• Embedded pipe cooling, whereby a series of evenly spaced pipe coils are circulated with refrigerated water, is used to limit concrete temperature in mass foundations. This method is expensive and used only when other less expensive methods are not sufficient.
• Use of Liquid Nitrogen is an expensive mode of cooling concrete.

Effective communication is a pillar of successful organization.
Communication flow can be upwards, downwards, lateral within the organization. Communication of information can be internal and external. A committed leadership shall be able to communicate the quality policy to the entire organization through effective means of communication. They shall be able to effectively communicate with the internal and external customers.
Some organizations compile excellent policies and procedures and completely or partially fails to communicate them to the stake holders, resulting in unsuccessful performance.
To create quality awareness, we need to present information in different languages for various classes of employees in an organization.
Let us discuss the languages of communication within various segments of organization as illustrated in the below pyramid.
At the top management level, creating an awareness of quality is best done in the language of money. The financial benefit of quality is of interest at the top level. Advantages of quality and its influence on customer is best discussed in this level and cascaded to the rest through effective communication tools. Understanding the market place threats to sales income, cost of poor quality and removing the obstacles in implementing a quality culture are part of top management discussion.

Middle management must understand the language of Top management and language of work force below them. They are bilingual and must communicate between Top and low management, effectively. They act as the “communication bridge” in any organization.
Lower management and nonsupervisory employees mostly use the language of products. They are giving life to the product as per set of instructions and procedures communicated to them. Effective communication from top management shall reach them to sustain the quality of product or service.
Translating the importance and impact of quality on customer satisfaction, directly in to language of job security, will dramatically induct quality awareness in middle and lower management. Often the business lost in “millions of rupees” due to “poor quality” is not communicated effectively to middle and low management, in terms of money and the lost possibilities of generating further job opportunities.

“Communication works for those who work at it.” John Powell

SHYAM KUMAR SYAMA PRASAD

Recipe for Quality ‘Concrete construction’ – Total Quality Management
Segment 4 - Commitment, Communication & Culture – the 3 C’s

As discussed earlier, the core of TQM is the customer-supplier interfaces.
The customer-supplier core must be surrounded by the 3 C’s, commitment to quality, communication of the quality message, and recognition of the need to change the culture of the organisation to create total quality. These are the foundations of Total Quality Management.

Commitment:

To achieve any goal, we shall build real feeling of commitment in all stake holders. Commitment shall not be forced up on, it shall evolve through right thinking processes. Leadership commitment is the foundation of any organization. A true leader shall have commitment to his cause. Without his/ her commitment, they will not be able to create a culture of quality in the organization. The success also depends on how effectively the leader communicate with his people.

Often, some organizations adopt or initiate Quality Management Systems (QMS) for getting certified by a third party (e.g.: ISO certification), which may be a pre requisite for winning a commercial order or to get approved / accepted by Governmental or Local authorities and other customers. In some cases, the Top management consider the QMS certification process as an exercise only to build the image.
In my professional career, I had a company owner who considered ISO 9001:2000 certification and QMS as a means to get approval from the local authority to run his ready- mix concrete business. He thought that the system is just documentation process and audits are useless exercises. Fortunately, reality from few incidents taught him that non committed leadership in Quality Management leads to “non committed customers” and inconsistent business, beside incurring huge financial losses due to repair and restoration process to correct the quality issues.

The actual “quality cost” (cost of poor quality) turns out to be much higher than what was being estimated by the managers, in some cases more than 20% of sales value. This is a subject of research and to be discussed separately.

The real advantages of a well-established Quality Management system and its commercial possibilities are not understood by some organizations. Non- committed and ignorant management and employees results in inferior quality products and services that leads to negative customer responses.

Commitment to produce good quality cement & concrete shall be supported by commitment to protect the environment, create sustainable and resilient products.
Major cement and concrete manufacturers are committed to the “zero carbon target” by 2050 in compliance with Paris agreement 2019.
Do you think the industry can achieve this target without commitment of the leadership and other stake holders? Answer is “absolutely not”
The message is clearly communicated to all stake holders and we all wish the commitment will be communicated and the required culture will be created for the benefit of our world.
We shall discuss about importance of communication and culture in Part 2

Commitment is what transforms promise in to a reality

- Abraham Lincoln

CETARC PRIIVATE LIMITED has been established to serve as a total solution provider to Ready Mix Concrete Industry and to its stake holders, who are the Civil Engineers, Consultants, Contractors, Developers, Government Organizations and the Construction Industry.

Our Vision

“CETARC aspires to be the leading consultant, solution provider and mentor in the region, by creating “concrete” awareness in sustainable ready- mix concrete with emphasis on construction quality control for the benefit of our society.

Our Mission

“Our mission is to support the stake holders of the ready mix concrete Industry - civil engineers, builders, developers, government agencies, consultants, contractors, ready mix companies and any other customers , assist them to successfully achieve their goals for specifying, buying, producing, selling, using concrete for sustainable development , ensuring adequate profitability to the producer and ultimate satisfaction to the end users. We shall also dedicate our efforts in creating a responsible engineering society with focus on executing sustainable concrete construction with excellent quality control for future generations”

Our Services include:

Training

Technical training in various areas of ready- mix concrete manufacturing, concrete technology and construction quality management.

Testing

Venturing into quality control testing of concrete and construction materials.

Auditing

Preparing the ready- mix concrete plant for RMCMA accreditation and assessing the quality management system of production facilities.

Repair & Restoration

Comprehensive investigation of quality issues in concrete structures, repair and restoration.

Consultancy

Consultancy and management services for ready mix concrete manufacturing industry.