Er. Chirag K Baxi, Director, Prudent Forensic Consultancy Private Limited., & General Manager, K K Retroflex Solutions
Quality assurance and adherence are fundamental requirements for any activity. However, it’s often observed that when the time frame for executing activities is compressed, quality tends to be compromised, leading to the need for subsequent rectification or rework.
However, when a commitment to quality adherence is the ‘Default’ approach, it is less likely to be influenced by the shortening of execution time.
Here are some phrases commonly heard in situations where the relationship between quality and timeframe is inversely proportional:
“I apologise for missing the last bag of cement during the site concreting.”
“I’m sorry for forgetting to remove burrs from the welding due to haste.”
“I overlooked removing extra nails from the support in a hurry, which resulted in an injury. I am sorry.”
“I could only spread a small amount of sand after applying bituminous coating to the road because I ran out of time. I apologise for the slip accident.”
How often do similar apologies arise when basic quality is compromised due to time constraints?
Quality is a mindset.
Quality is a mental attitude.
Quality is a tool for perfection.
Quality should never be sacrificed, whether due to time constraints or economic reasons. By prioritising quality alongside speed, we can achieve excellence without compromising on either aspect.
Er. Chirag K Baxi, Director, Prudent Forensic Consultancy Private Limited., & General Manager, K K Retroflex Solutions
Formwork is that activity which is carried out just before taking up the final action of pouring concrete or that material which is designed for an element to be constructed.
Every week is a ‘QUALITY WEEK’ so it is an appropriate thought to deliberate on quality issues in construction actions.
Formwork or shuttering – as said above, undoubtedly stands on high number in the list of quality tools for construction actions. It is not just a container to hold the mass in liquid or semi liquid stage till it attains self standing status. It has few more important functions to perform as discussed below.
The prime function of formwork is certainly to hold the mass poured within its volume till the mass attains self standing status.
Additionally, it plays an important role in giving the finally desired shape to the element under construction / creation. Columns, beams, slab etc of the designed shape either by a structural engineer or an architect can be created only with the help of appropriately and accordingly designed and erected formwork / shuttering.
Strong formwork / shuttering ensures that it would retain position of all if it’s components throughout the process of the material being poured within its volume. None of its part would dislodge or succumb under lateral or vertical pressure being experienced. Adequately strong and tightly anchored supports for the components of formwork / shuttering, perform this task.
One of the most important contribution of formwork / shuttering which makes it significantly a quality tool, is its watertightness. It is always essential for a formwork / shuttering to be watertight. Not a single drop of the mass being poured inside its volume should leak out of any of its component/s. The very fact that every drop of mass being poured within its volume contains precious part of the mass; to be a part of the total mass required for that element and to be essentially available in the mass poured within the volume of formwork / shuttering. That leaking drop/s might take away equivalent quantity of cement or micro-concrete or epoxy etc from that mass within the formwork and as a result, that mass would polymerise without that equivalent quantum of the lost precious component. Such events result in under-performance of the constructed member in time to come.
Very close to formwork is reinforcement steel for any RCC member. Quality aspects of reinforcement will be discussed in next write up.
Erection / placing reinforcement steel – a quality statement
Subsequent to deliberating views on different quality aspects on formwork / shuttering, let us discuss quality aspects connected with erection of reinforcement steel. Few important points to be ensured for adhering to quality in execution of reinforcement steel erection are placed here.
Maintaining the specified depth of cover: Depth of cover holds an important key for performance of reinforcement steel as desired of it. This is achieved by placing cover / distance blocks manufactured with similar material and strictly maintaining plumb / line & level of reinforcement bars. Missing any of these would certainly lead to the stage from where either reinforcement steel would corrode (with inadequate depth of cover) or would deflect (with improper horizontal or vertical alignment because stresses generate along a perticular plane and if reinforcement steel is not positioned along that line / plane then stress compensation doesn’t happen).
Laps: Lap length of 50 X diameter of reinforcement bar is absolutely essential and equally essential is staggering the laps. Laps should not be placed in one line (horizontal or vertical because that makes it a weak plane which can become line of failure.
Corroded reinforcement: It must be made mandatory for removing rust from each reinforcement bar before it’s erection and also before formwork is erected. Though it takes nearly 40 months for reduction of every one milimeter of diameter of reinforcement bar, concreting with trusted reinforcement bar, concreting with trusted reinforcement bar makes it a weak RCC element right from the time of its initial set.
Few images of results of not following standard quality practice for erection of reinforcement steel at site are placed here which are self explanatory.
Formwork and reinforcement are integral parts of RCC element. Both of them inculcate quality for the RCC element so an equal importance is to be given to both of them as to he given to concreting activity.
Er. Chirag K Baxi, Director, Prudent Forensic Consultancy Private Limited., & General Manager, K K Retroflex Solutions
Corrosion can weaken buildings and structures, gradually damaging them and leading to costly repairs over time. To mitigate this, the need of this hour is to appropriately analyze the causes of corrosion and come out with the appropriate solution. Addressing these, requires experts who can blend knowledge from concrete, material science, civil engineering, and advanced testing methods.
In regard to this, Constrofacilitator.com recently had a conversation with Er. C K Baxi, a distinguished specialist in Concrete Technology & Forensic Engineering. He currently serves as the Technical Director at Prudent Forensic Consultancy Private Limited and holds the position of General Manager at K K Retroflex Solutions. He is a highly skilled specialist with a profound comprehension of materials, corrosion mechanisms, and failure analysis. In his role as a consultant for Corrosion and Forensic Engineering, he excels in offering diagnostics, mitigation strategies, and rehabilitation solutions.
During the interview, he shared insights encompassing the overview of corrosion and forensic engineering, assessment methods, approach techniques, and emerging technologies.
Here are the excerpts from the inerview.
Can you provide an overview of your experience in corrosion and forensic engineering, as well as the types of projects you’ve worked on? What types of corrosion can structures experience?
I’ve handled assignments involving corrosion in both concrete and steel structures. It might seem unconventional, but concrete can indeed undergo corrosion, primarily through the depolarization of cement. This results in heterogeneity and loss of integrity within the concrete matrix. Such corrosion is common in structures exposed to corrosive chemicals and conditions.
Concrete corrosion presents signals that must be timely detected for detailed investigation, preferably through non-destructive testing. An extensive analysis and evaluation of test results help establish links between different conditions causing damage, leading to the identification of root causes. This is essential for designing structural rehabilitation plans to prevent recurrence of damage.
Concrete corrosion indicators include:
Spalling
Surface cracks with significant depth/width
Exposed reinforcement bars
Honeycomb effects on the surface
Various concrete concrete corrosion indications- spalling, surface cracks and exposed reinforced bards
Identifying steel corrosion is comparatively easier, as the visible rust product on the surface indicates its presence. Types of steel corrosion include mild, medium, severe, and spot/dot corrosion. Corroded steel structures should undergo relevant tests to determine the extent and seriousness of corrosion-induced damage. Reverse engineering is crucial for designing structural rehabilitation plans for such cases.
As a Corrosion Engineering expert, how do you assess potential corrosion risks in critical structures, both steel and concrete?
The potential risks in critical or non-critical structures due to corrosion involve the loss of integrity in concrete or steel members. Depolarization of the matrix leads to loss of homogeneity, causing aggregates in concrete and web/flange in steel members to function independently, an unhealthy situation.
Understanding corrosion chemistry for both concrete and steel structures is sometimes essential. The corrosion process, causal conditions, and atmospheric factors need careful examination, as they vary with each assignment.
In forensic engineering, how do you differentiate between corrosion-related failures and failures caused by other factors like material defects?
Distinguishing between corrosion-related failures and other causes is a crucial step in designing corrosion mitigation strategies. Forensic Engineering relies on test results, much like how medical tests aid pathologists in diagnosing illnesses. Damaged concrete or steel members must undergo relevant tests, predominantly non-destructive ones, although a few might involve particle puncturing.
A correlation between the test results and standard parameters, tested during the examination, is crucial. Visual inspection and observations help correlate deviations in test results. For instance, a “good” rebound hammer test result for concrete doesn’t necessarily mean good compressive strength; it might be due to carbonation effects if the depth of carbonation equals or exceeds the cover depth.
Corrosion-related failure and failure due to material defect
In your experience, what are common misconceptions about corrosion’s effects on steel and concrete structures?
Common misunderstandings exist in both steel and concrete corrosion. Common misconceptions are briefly addressed below:
Steel Corrosion:
Severity of corrosion varies with steel surface exposure to corrosive conditions. Dot or spot corrosion isn’t always serious.
Sustained corrosion leads to member thickness reduction, impacting load-sharing capacity. Regular examination of corroded steel surfaces is crucial.
Corrosion accelerates faster in corners and angles compared to plain surfaces.
Concrete Corrosion:
Concrete corrosion occurs due to depolarization of the matrix, causing a loss of cement’s binding properties.
What emerging technologies or methodologies in corrosion and forensic engineering do you find promising?
Forensic Engineering begins with precise testing to identify parameters that trigger the need for investigation. Various testing methods for concrete and steel regularly undergo upgrades due to evolving damage patterns. Emerging tests include thermography for concrete and drone surveys and tomography for corroded concrete and steel members.
How do you effectively communicate your findings and recommendations to clients, stakeholders, or non-technical individuals?
After testing, systematic record-keeping is vital, following internationally accepted standards. Forensic Engineering-based presentation of results requires comprehensive interpretation, evaluation, and analysis. Report preparation is an art mastered to convey case facts in a simple and understandable manner to clients.
Corrosion Testing
What advice would you offer to aspiring engineers interested in specializing in corrosion and forensic engineering?
I would impart three principles: cultivate a genuine passion for your work, maintain a deep commitment to your assignments, and view failures as stepping stones for improvement. It’s vital for engineers to have a firm grasp of foundational concepts to effectively analyze challenging conditions. Test results are only figures; true insight is gained when those figures are grounded in a solid understanding of fundamentals. This forms the bedrock of forensic engineering analysis.
