This study introduces the need, difficulties associated with and solutions for implementing the use of High Strength Concrete in Peshawar and challenging areas in general. It does so by using Peshawar as a case study and generalizing its characteristics to any other such regions in the world.
It reviews current standard methods for making High Strength Concrete in the world and investigates those used in the target region. Then compares them to find the difficulties that stand as a hindrance in achieving High Strength Concrete in said area, naming them as challenges. It uses the PEC (Pakistan Engineering Council) contractors’ categorization to provide guidelines for each category to tackle the challenge that hinders it the most. Furthermore, it provides a set of actions for PEC to follow for a successful implementation of High Strength Concrete in the area. It also gives a review of the process for use in other challenging environments, also giving examples of such environments in Pakistan and other parts of the world.
Table of Contents
Chapter 1. Introduction
1.1 The Construction Industry in Peshawar
1.2 Limitations of the current practices
1.2.1 Standard Methods of Design and Practice
1.2.2 Standard Process of Construction
1.2.3 Standard Construction Practices
1.2.4 What happens in Peshawar?
1.2.5 The Problem
1.3 High Strength Concrete
1.3.1 Education of the General Public
1.3.2 Using materials with higher strength
1.3.3 Conclusion
1.3.4 Further Discussion
1.4 Problem Statement (A Challenging Environment)
1.5 Peshawar As A Case Study
1.6 Scope and Significance
1.6.1 Significance
1.6.2 Scope
1.7 Approach
Chapter 2. Literature Review
2.1 Concrete
2.1.1 Concrete
2.1.2 Portland cement as Hydraulic Binder
2.1.3 Aggregates
2.1.4 Cement Hydration and Concrete formation
2.1.5 Fresh Concrete and its transport, placement problems
2.1.6 Concrete Strength and Failure Mechanism
2.1.7 Factors affecting the strength of concrete
2.1.8 Reinforced Concrete
2.1.9 Importance
2.2 High Strength Concrete (363, 2010)
2.2.1 Definition
2.2.2 Materials for Production
2.2.3 Proportioning
2.2.4 Fresh HSC
2.3 Specifications
2.3.1 Cement
2.3.2 Course and Fine Aggregates
2.3.3 Silica Fume
2.3.4 HRWR
2.4 A New Method Of Mixing
2.4.1 Mechanism of Failure in Concrete
2.4.2 Delaying Bond Failure
2.4.3 Silica Fume
2.4.4 Need for Dispersion
2.4.5 New Method of Mixing (Lewis, 2019)
Chapter 3. Methodology
3.1 Defining HSC In Peshawar
3.1.1 Data of Cylinder Tests
3.1.2 Laboratory Tests
3.1.3 Borderline
3.2 Availability of Materials
3.2.1 Cement
3.2.2 Sand
3.2.3 Aggregate
3.2.4 Silica Fume
3.2.5 HRWR
3.3 Construction Practices in Peshawar (Zada, 2019)
3.3.1 Two Categories
3.3.2 Mix Design or Proportioning
3.3.3 Fresh HSC
3.3.4 Gallery
3.4 Challenges
3.4.1 Formulation of Strength Required (318, 2011)
3.4.2 Aggregate Ratios
3.4.3 Use of SCMs and Admixtures
3.4.4 Quality Control and Testing
3.4.5 Batching Plants and SD
3.4.6 Industry Acceptance
3.5 Categorization
3.5.1 Categories and Solutions to Challenges for Each
3.6 Role of the Authorities
3.6.1 Stage-I
3.6.2 Stage-II
Chapter 4. Conclusion
4.1 Expanding Horizons
4.2 Examples
4.2.1 Lahore (Space)
4.2.2 Gilgit (Soil)
4.2.3 Kashghar (Conflict)
4.3 Conclusion
Objectives and Research Themes
The primary objective of this research is to facilitate the implementation of High Strength Concrete in Peshawar and similar "challenging environments" by amending existing construction protocols and providing new, practical methodologies that accommodate local limitations.
- Analysis of local construction practices in Peshawar as a case study.
- Definition of a "challenging environment" within the context of infrastructure development.
- Development of practical mixing and proportioning methods for High Strength Concrete tailored to local constraints.
- Categorization of construction contractors to provide scalable guidelines for implementation.
- Recommendations for authoritative bodies to bridge the gap between international standards and local construction realities.
Excerpt from the Book
A New Method Of Mixing
To properly disperse the silica fume throughout the concrete, a new method is being used in many parts of the globe.
Method (Copied as is)
This procedure has been developed over many years to give a sequence that is optimum for the mixing and dispersion of silica fume into a concrete mix, particularly with a small batch for a trial. If the silica fume is not fully dispersed, the reactivity and effects of the material can be less than expected. Following the steps in this sequence will give the maximum benefits from incorporating the silica fume. Please also see the notes after the sequence.
1. Put all the coarse aggregate and 50% of the fine aggregate into the mixer with 75% of the water. Start the mixer.
2. When evenly mixed, add the silica fume. The preference here is to use undensified powder or slurry. Densified powder can be used, but extra time must be allowed here to break down the particles. This would be up to 2 minutes.
3. Once evenly mixed – to a uniform grey color – add the cement and allow to mix in.
4. Then evenly mixed, add the rest of the fine aggregate and allow to mix in.
5. Add the remaining water, slowly, until the required workability is reached. If the workability is low, adjust the superplasticiser – keep the water/binder ratio as designed.
Summary of Chapters
Chapter 1. Introduction: Outlines the construction industry's state in Peshawar, identifying the lack of engineered standards and proposing High Strength Concrete as a solution to space and safety constraints.
Chapter 2. Literature Review: Provides a theoretical basis regarding concrete composition, properties, and standard high-strength production methods, including the use of silica fume.
Chapter 3. Methodology: Details the empirical research conducted, including cylinder testing data, the assessment of local material availability, and the classification of contractors for implementing new standards.
Chapter 4. Conclusion: Summarizes the methodology's applicability to other challenging regions globally and provides a roadmap for policy implementation.
Keywords
Peshawar, High Strength Concrete, Challenging areas, Construction industry, Silica fume, Material proportioning, Infrastructure development, Quality control, PEC categorization, Concrete mixing, Structural safety, Standard protocols, Admixtures, Cement hydration, Civil engineering
Frequently Asked Questions
What is the core focus of this thesis?
The thesis focuses on the challenges of implementing High Strength Concrete (HSC) in Peshawar, Pakistan, and developing practical, site-specific methods to overcome these hurdles.
Which regions are considered "challenging environments"?
These are areas where standard engineering protocols and international building codes are difficult to implement due to local social, economic, or technical constraints.
What is the primary research goal?
The goal is to provide amended construction protocols and actionable guidelines for different categories of contractors to successfully use High Strength Concrete in a challenging environment.
How is the construction industry in Peshawar evaluated?
The industry is evaluated through a case study approach, comparing standard international methods with local practices, utilizing cylinder test data, and analyzing local material limitations.
What does the methodology include?
The methodology includes setting a "borderline" strength for HSC in Peshawar, benchmarking against international standards, and providing a step-by-step mixing sequence to ensure proper material dispersion.
What are the primary construction challenges identified?
Key challenges include lack of standard deviation data in production, absence of specialized materials like silica fume, reliance on outdated "thumb rule" ratios, and limited acceptance of rigorous quality control.
Why is silica fume significant in this study?
Silica fume is critical for replacing calcium hydroxide in the concrete's transition zone, which effectively densifies the structure and allows for the achievement of higher concrete strengths.
What role does the PEC play?
The Pakistan Engineering Council (PEC) is identified as the authoritative body capable of enforcing and facilitating the gradual transition to standard High Strength Concrete practices across different contractor tiers.
Does this study provide cost-saving strategies?
Yes, the study uses a System Dynamics model to demonstrate that increasing concrete strength allows for reduced element sizes, which provides more usable space and offsets overall costs.
How should a C-3 category contractor proceed?
Contractors in this tier are advised to adopt specific measures such as utilizing 6% silica fume, implementing water-reducing admixtures, and using defined aggregate ratios of 1:0.5:1.5.
- Arbeit zitieren
- Omair Shafiq (Autor:in), Abdul Jabbar (Autor:in), Ghufran Ullah (Autor:in), 2019, Achieving High Strength Concrete in challenging areas, München, GRIN Verlag, https://www.grin.com/document/496075
