Thermogravimetric Analysis of Limestone Aggregates for Portland Cement Concrete

1998 ◽  
Vol 1619 (1) ◽  
pp. 37-44
Author(s):  
Stephen A. Cross ◽  
Mohamed Nagib Abou-Zeid
Keyword(s):  
Weight Loss ◽  
Thermogravimetric Analysis ◽  
Portland Cement ◽  
Coarse Aggregate ◽  
Pavement Performance ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
The Past ◽  
Good Potential ◽  
Durability Assessment

Durability of coarse aggregate has a major impact on the durability of portland cement concrete. Over the past years, there has been an increasing interest in developing and improving test techniques that provide a more accurate durability assessment, which ultimately leads to a better prediction of pavement performance. Thermogravimetric analysis is a relatively rapid technique that has shown good potential for use in the analysis of carbonate aggregates. Thermogravimetric technique (TG) was used to analyze 31 limestone aggregates. The specimens were heated to temperatures above 1000°C using two rates of temperature increase. The weight loss and the change in weight loss as a function of temperature were recorded. Results show a correlation between the slope before calcite transition and some durability aspects of limestone. Moreover, the TG output can be used to calculate the percent acid insoluble (AI) and the pavement vulnerability factor (PVF). Therefore, TG may be considered as a rapid method for AI and PVF determination.

A Different Perspective for Investigation of Portland Cement Concrete Pavement Deterioration

1996 ◽  
Vol 1525 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Vernon J. Marks ◽  
Wendell G. Dubberke
Keyword(s):  
Portland Cement ◽  
Coarse Aggregate ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Air Voids ◽  
Pavement Deterioration ◽  
Cement Concrete Pavement ◽  
The Matrix ◽  
History Of ◽  
Crushed Limestone

Many early Iowa portland cement concrete (PCC) pavements provided good performance without deterioration for more than 50 years. In the late 1950s, Iowa was faced with severe PCC pavement deterioration called D-cracking due to crushed limestone containing a bad pore system. Selective quarrying solved the problem. In 1990, cracking deterioration was identified on a 3-year-old US-20 pavement in central Iowa. The coarse aggregate was a crushed limestone with an excellent history of performance in PCC pavement. Examination of cores showed very few cracks through the coarse aggregate particles. The cracks were predominately confined to the matrix. A high-resolution, low-vacuum Hitachi scanning electron microscope with an energy dispersion detector was used to investigate the deterioration. Subsequent evaluation identified a very small concentration of silica gel (silicon) but substantial amounts of sulfur and aluminum (assumed to be ettringite) in the air voids. Some of these voids have cracks radiating from them leading to the conclusion that the ettringite-filled voids were centers of pressure causing the cracks. The ettringite in the voids, after being subjected to sodium chloride brine, initially swelled and then dissolved. The research has indicated that the premature deterioration may be due to ettringite and may have been mistakenly identified as alkali-silica reactivity.

Durability assessment of self-healing in ordinary Portland cement concrete containing chemical additives

2021 ◽  
Vol 305 ◽  
pp. 124754
Author(s):  
Konstantinos Aspiotis ◽  
Konstantinos Sotiriadis ◽  
Anna Ntaska ◽  
Petra Mácová ◽  
Efstratios Badogiannis ◽  
...  
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Self Healing ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Chemical Additives ◽  
Durability Assessment ◽  
Ordinary Portland Cement Concrete

The Great Unsealing: A Perspective on Portland Cement Concrete Joint Sealing

1997 ◽  
Vol 1597 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Stephen F. Shober
Keyword(s):  
Portland Cement ◽  
National Level ◽  
Cost Effective ◽  
Transportation System ◽  
Pavement Performance ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Wisconsin Department ◽  
Crack Sealing ◽  
Contraction Joints

The general mission of most transportation agencies is to ensure a customer focus in the development and operation of a safe and efficient transportation system. The customers desire comfort, convenience, safety, and cost-effectiveness in a transportation system. Agency research must have the objectives of addressing customer-related issues and measuring benefits of importance to them. Accordingly, any joint and sealant research must answer the questions, Why do we seal? and Is it cost-effective? Joint and sealant studies of portland cement concrete (PCC) pavements must address whether joint sealing enhances total pavement performance and is cost-effective, and, if so, what sealant system should be used. The Wisconsin Department of Transportation (WisDOT) has been studying the effect of PCC joint/crack sealing on total pavement performance for 50 years. By 1967 there was substantial documentation that filling and refilling of contraction joints had no beneficial effect on pavement performance. By 1984, it was concluded that pavements with unsealed joints had better overall performance (distress, ride, materials integrity) than pavements with sealed joints. In 1990, WisDOT passed a policy eliminating all PCC joint sealing, in new construction and maintenance. This "no-seal" policy has saved Wisconsin $6,000,000 annually with no loss in pavement performance and with increased customer safety and convenience. The entire PCC sealing issue is beginning to be addressed at the national level, ensuring no false assumptions and with the customer’s needs in view.

scholarly journals Quantification of Segregation in Portland Cement Concrete Based on Spatial Distribution of Aggregate Size Fractions

2020 ◽  
Vol 39 (3) ◽  
pp. 147-159
Author(s):  
Murat Ozen ◽  
Murat Guler
Keyword(s):  
Spatial Distribution ◽  
Portland Cement ◽  
Cross Section ◽  
Coarse Aggregate ◽  
Hardened Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Segregation Index ◽  
Size Fractions ◽  
Quality Control Tool

Segregation is one of the quality standards that must be monitored during the fabrication and placement of Portland cement concrete. Segregation refers to separation of coarse aggregate from the cement paste, resulting in inhomogeneous mixture. This study introduces a digital imaging based technique to quantify the segregation of Portland cement concrete from 2D digital images of cut sections. In the previous studies, segregation was evaluated based on the existence of coarse aggregate fraction at different geometrical regions of a sample cross section without considering its distribution characteristics. However, it is shown that almost all particle fractions can form clusters and increase the degree of segregation, thus deteriorating the structural performance of concrete. In the proposed methodology, a segregation index is developed by based on the spatial distribution of different size fractions of coarse aggregate within a sample cross section. It is shown that degradation in mixture’s homogeneity is controlled by the combined effect of particle distribution and their relative proportions in the mixture. Hence, a segregation index characterizing the mixture inhomogeneity is developed by considering not only spatial distribution of aggregate particles, but also their size fractions in the mixture. The proposed methodology can be successfully used as a quality control tool for monitoring the segregation level in hardened concrete samples.

Assessment of Distress in Conventional Hot-Mix Asphalt and Asphalt–Rubber Overlays on Portland Cement Concrete Pavements

2005 ◽  
Vol 1929 (1) ◽  
pp. 20-27
Author(s):  
Maria Carolina Rodezno ◽  
Kamil E. Kaloush ◽  
George B. Way
Keyword(s):  
Portland Cement ◽  
Large Scale ◽  
Hot Mix Asphalt ◽  
Field Performance ◽  
Fatigue Cracking ◽  
Pavement Performance ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Asphalt Rubber ◽  
Design Guide

The purpose of this study is to assess the way distresses are predicted by using the new Mechanistic–Empirical Design of New and Rehabilitated Pavement Structures (design guide), developed under NCHRP Project 1–37A. Two pavement sections were used: a conventional hot-mix asphalt reconstruction and an asphalt–rubber overlay on a portland cement concrete (PCC) pavement. The design guide does not include rehabilitation design for asphalt–rubber overlays. However, many large-scale asphalt–rubber overlays on interstate highways in Arizona have been built and monitored for performance, providing an opportunity to determine to what degree the design guide can predict their performance. The input data for both types of pavements were derived from two different projects on the same highway, Interstate 40. The actual data measurements that summarize the pavement performance were compared with calculated values obtained by using the design guide. Three pavement performance parameters were evaluated on the basis of the available data: rutting, cracking, and international roughness index (IRI). Rutting was one of the distresses that the design guide predicted more accurately. The fatigue cracking prediction, evaluated with Level-3 data input, was not accurate; future analysis should consider calibrated fatigue models for the different mixtures. The predicted IRI results differed from the actual measured field performance because of inaccurate distress prediction. The Arizona experience using asphalt–rubber overlays to rehabilitate aged PCC pavements has been successful. For that reason, a calibration process that allows the use of the asphalt–rubber mixtures in the design guide should be considered in the future.

scholarly journals A Mini Review on Properties of Portland Cement Concrete with Geopolymer Materials as Partial or Entire Replacement

2021 ◽  
Vol 6 (2) ◽  
pp. 26
Author(s):  
Kong Fah Tee ◽  
Sayedali Mostofizadeh
Keyword(s):  
Portland Cement ◽  
Experimental Tests ◽  
Alkaline Solutions ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
The Past ◽  
Laboratory Results ◽  
Temperature Water ◽  
Chemical Materials ◽  
Significant Factors

The main aim of this paper is to review recent studies over the past 10 years investigating the influencing factors for improving the mechanical properties of concrete. This focuses on concrete comprising of pozzolanic materials, partially or entirely replacing ordinary Portland cement, in the concrete mixture. Firstly, the effectiveness of main factors such as temperature, water to solid (W/S) ratio, and alkaline solution ratio was briefly discussed. Next, the effects of significant factors such as different superplasticizer and alkaline solutions and combinative materials on the improvement of concrete workability were reviewed and compared. Eventually, other concrete properties such as water absorption and durability were discussed in the last section. After reviewing all types of concrete additives, including mineral or chemical materials, the influence of these admixtures under different laboratory conditions were highlighted to objectively evaluate the benefits of each factor. As a whole, the significant reasons of such experimental tests arising from the usage of these materials, in accordance with the laboratory results obtained from these investigations, are discussed.

Development of a Capacitor Probe to Detect Subsurface Deterioration in Concrete

1997 ◽  
Vol 503 ◽  
Author(s):  
B. K. Diefenderfer ◽  
I. L. Al-Qadi ◽  
J. J. Yoho ◽  
S. M. Riad ◽  
A. Loulizi
Keyword(s):  
Dielectric Constant ◽  
Portland Cement ◽  
Electromagnetic Waves ◽  
Low Cost ◽  
Complex Dielectric Constant ◽  
Life Cycle Costs ◽  
Parallel Plates ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Set Up

ABSTRACTPortland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. By developing techniques that would enable civil engineers to evaluate PCC structures and detect deterioration at early stages (without causing further damage), optimization of life-cycle costs of the constructed facility and minimization of disturbance to the facility users can be achieved.Nondestructive evaluation (NDE) methods are potentially one of the most useful techniques ever developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part, termed the “loss factor,” describes the conductivity of PCC and the attenuation of electromagnetic waves.Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1 to 40.1MIHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation. A new capacitor probe has been developed which consists of two plates, located within the same horizontal plane, for placement upon the specimen to be tested. Preliminary results show that this technique is feasible and results are promising; further testing and evaluation is currently underway.

Sign in / Sign up

Export Citation Format

Share Document