Author: Shervin JahangirnejadPublisher:
ISBN:
Category : Aggregates (Building materials)
Languages : en
Pages : 330
Book Description
Evaluation of Portland Cement Concrete Coefficient of Thermal Expansion Test Protocol and the Impact of CTE on Performance of Jointed Concrete Pavements
Author: Shervin JahangirnejadPublisher:
ISBN:
Category : Aggregates (Building materials)
Languages : en
Pages : 330
Book Description
Construction Materials and Structures
Author: S.O. EkoluPublisher: IOS Press
ISBN: 1614994668
Category : Technology & Engineering
Languages : en
Pages : 1562
Book Description
The two volumes of these Proceedings contain about 200 conference papers and 10 keynote papers presented at the First International Conference on Construction Materials and Structures, held in Johannesburg, South Africa from 24 to 26 November 2014. It includes sections on Materials and characterization; Durability of construction materials; Structural implications, performance, service life; Sustainability, waste utilization, the environment; and Building science and construction.
Quantifying Coefficient of Thermal Expansion Values of Typical Hydraulic Cement Concrete Paving Mixtures
Author: Neeraj J. BuchPublisher:
ISBN:
Category : Aggregates (Building materials)
Languages : en
Pages : 0
Book Description
A laboratory investigation was conducted to determine the coefficient of thermal expansion (CTE) of a typical Michigan Department of Transportation (MDOT) concrete paving mixture made with coarse aggregate from eight different sources. The primary aggregate class included limestone, dolomite, slag, gravel and trap rock. The CTE was determined using the provisional AASHTO TP60 protocol. Three replicate test specimens were fabricated for each mixture-age combination. Furthermore, the report also discusses the practical (significance) impact of the test variables on the transverse cracking performance of jointed plain concrete pavements.
Effect of Portland Cement Concrete Characteristics and Constituents on Thermal Expansion
Author: Md Sarwar SiddiquiPublisher:
ISBN:
Category :
Languages : en
Pages : 408
Book Description
The coefficient of thermal expansion (CTE) is one of the major factors responsible for distresses in concrete pavements and structures. Continuously reinforced concrete pavements (CRCPs) in particular are highly susceptible to distresses caused by high CTE in concrete. CRCP is a popular choice across the U.S. and around the world for its long service life and minimal maintenance requirements. CRCP has been built in more than 35 states in the U.S., including Texas. In order to prevent CRCP distresses, the Texas Department of Transportation (TxDOT) has limited the CTE of CRCP concrete to a maximum of 5.5 x10-6 strain/oF (9.9 x10-6 strain/oC). Coarse aggregate sources that produce concrete with CTE higher than the allowable limit are no longer accepted in the TxDOT CRCP projects. Moreover, CTE is an important input in the Mechanistic-Empirical Pavement Design Guide (MEPDG). Small deviations in input CTE can affect the pavement thickness significantly in MEPDG designs. Therefore, accurate determination of concrete CTE is important, as it allows for enhanced concrete structure and pavement design as well as accurate screening of CRCP coarse aggregates. Moreover, optimizing the CTE of concrete according to a structure's needs can reduce that structure's cracking potential. This will result in significant savings in repair and rehabilitation costs and will improve the durability and longevity of concrete structures. This study found that the CTEs determined from saturated concrete samples were affected by the internal water pressure. As a result, the TxDOT method yielded higher values than did the American Association of State Highway and Transportation Officials (AASHTO) method. To further investigate the effect of internal water pressure, an analytical model was developed based on the poroelastic phenomenon of concrete. According to the model, porosity, permeability, and the rate of temperature change are the major factors that influence the internal water pressure development. Increasing the permeability of concrete can reduce the internal water pressure development and can thus improve the consistency of measured CTE values. Preconditioning concrete samples by subjecting them to several heating and cooling cycles prior to CTE testing and reducing the rate of temperature change improved the consistency of the CTE test results. Concrete CTE can be reduced by blending low-CTE aggregates with high-CTE aggregates and reducing the cement paste volume. Based on these findings, a concrete CTE optimization technique was developed that provides guidelines for the selection of concrete constituents to achieve target concrete CTE. A concrete proportioning technique was also developed to meet the need for CTE optimization. This concrete proportioning technique can use aggregate from any sources, irrespective of gradation, shape, and texture. The proposed technique has the potential to reduce the cement requirement without sacrificing performance and provides guidelines for multiple coarse and fine aggregate blends.
Coefficient of Thermal Expansion of Portland Cement Concrete in Utah and Pavement Performance
Author: Michael Thomas RigbyPublisher:
ISBN:
Category : Concrete
Languages : en
Pages : 200
Book Description
Mechanistic-empirical Pavement Design Guide
Author: American Association of State Highway and Transportation OfficialsPublisher: AASHTO
ISBN: 156051423X
Category : Pavements
Languages : en
Pages : 218
Book Description
Effects of Concrete Age on Coefficient of Thermal Expansion of Paving Mixes and Its Significance in Unbonded Overlay Design
Author: Gauhar SabihPublisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 13
Book Description
With the advancement in rigid pavement design and advent of AASHTOWare Pavement Mechanistic-Empirical (ME) Design (American Association of State Highway and Transportation Officials, Washington, DC) as the latest design tool, increasing emphasis is being laid on the coefficient of thermal expansion (CTE) of concrete. The CTE affects the performance of rigid pavements in a significant manner, with a higher CTE corresponding to greater curling and resulting in greater pavement distresses. Prior research has conflicting views regarding CTE variation with age, and there has been very little to no research on the effects of CTE on the performance of unbonded concrete overlays (UBCOs). This study is performed to investigate the variation of CTE with concrete age through laboratory testing and further quantify the effects of CTE variation on UBCO design. To facilitate, four concrete paving mixes with different types of coarse aggregates and different mix properties from different districts of New Mexico were collected. The cast specimens from each of the mixes were tested for CTE as per the AASHTO T-336, Coefficient of Thermal Expansion of Hydraulic Cement Concrete , protocol, at the ages of 7, 14, 28, 60, 90, 120, and 180 days, respectively. The test results were analyzed, and it was observed that there is an increase in CTE over the range of 3.49 % to 9.77 %, between 28 days and 180 days. Further analysis was conducted with simulations in Pavement ME Design Version 2.3 ® that indicated a significantly deteriorated performance of the UBCO with increased CTE. The impact on transverse cracking and joint faulting is the most significant, with up to 13.3 % increase in cracking and up to 19.7 % increase in faulting distress. An unbonded overlay designed with 28 days CTE value may not perform for the design life because of the increase in CTE with age progression.
Summary Report on the Evaluation of Rigid Pavement Long-life Strategies
Author: David Jones (Engineer)Publisher:
ISBN:
Category : Pavements, Concrete
Languages : en
Pages : 84
Book Description
Comparison of Methods of Test for Coefficient of Linear Thermal Expansion of Concrete
Author: Field Measurement of Water-cement Ratio for Portland Cement Concrete
Author: Amy M. DowellPublisher:
ISBN:
Category : Concrete
Languages : en
Pages : 52
Book Description