scholarly journals Long-term performance of sustainable pavements using ternary blended concrete with recycled aggregates

2021 ◽  
Author(s):  
Gilson Lomboy ◽  
Douglas Cleary ◽  
Seth Wagner ◽  
Yusef Mehta ◽  
Danielle Kennedy ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cementitious Materials ◽  
Recycled Concrete ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Concrete Aggregates ◽  
Concrete Mixtures

Dwindling supplies of natural concrete aggregates, the cost of landfilling construction waste, and interest in sustainable design have increased the demand for recycled concrete aggregates (RCA) in new portland cement concrete mixtures. RCA repurposes waste material to provide useful ingredients for new construction applications. However, RCA can reduce the performance of the concrete. This study investigated the effectiveness of ternary blended binders, mixtures containing portland cement and two different supplementary cementitious materials, at mitigating performance losses of concrete mixtures with RCA materials. Concrete mixtures with different ternary binder combinations were batched with four recycled concrete aggregate materials. For the materials used, the study found that a blend of portland cement, Class C fly ash, and blast furnace slag produced the highest strength of ternary binder. At 50% replacement of virgin aggregates and ternary blended binder, some specimens showed comparable mechanical performance to a control mix of only portland cement as a binder and no RCA substitution. This study demonstrates that even at 50% RCA replacement, using the appropriate ternary binder can create a concrete mixture that performs similarly to a plain portland cement concrete without RCA, with the added benefit of being environmentally beneficial.

Study of Durability of Recycled Concrete under the Environment of the Acid Rain

2011 ◽  
Vol 71-78 ◽  
pp. 5042-5045 ◽  
Author(s):  
Xiao Xiong Zha ◽  
Jun Kai Lu
Keyword(s):  
Portland Cement ◽  
Mass Loss ◽  
Acid Rain ◽  
Experimental Studies ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Crushing Strength ◽  
Recycled Concrete Aggregates

Due to the rough surface of the recycled concrete aggregates, low modulus of elasticity and large porosity, these properties led to that the apparent density, strength, physical properties and durability of the recycled concrete made by recycled aggregates are different from the Portland cement concrete, so that the standards and requirements formed about the Portland cement concrete are not entirely suitable for the recycled concrete. On the basis of the experimental studies, this paper analyzes the differences of mass loss, crushing strength and neutralization depth between the ordinary Portland concrete and recycled concrete under the influence of simulation acid rain. The results showed that there are different degrees of change between the concrete with 100% aggregates instead of recycled aggregates and the Portland concrete in mass loss, crushing strength and neutralization depth under the influence of simulation acid rain.

scholarly journals Development and Guidance of Green Concrete for Leed™ Applications

2010 ◽  
Vol 5 (4) ◽  
pp. 111-120
Author(s):  
John T Kevern
Keyword(s):  
Green Building ◽  
Cementitious Materials ◽  
Recycled Concrete ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregate ◽  
Strength Development ◽  
Concrete Aggregate ◽  
Total Contribution ◽  
Recycled Materials ◽  
Concrete Mixtures

As green building rating systems such as LEED™ become more popular, the use of recycled materials in construction is increasing. Concrete can be produced with significant quantities of supplementary cementitious materials or recycled aggregate materials. However, modifying concrete mixture proportions for improved recycled content credits also impacts strength and long-term durability. Without properly understanding the effects recycled materials have on concrete, greener concrete can be less desirable from a lifecycle perspective from poor durability. This research investigates the impacts different types and quantities of supplementary cementitious materials and recycled concrete aggregate have on strength development and concrete durability, specifically deicer scaling. Improvements to deicer scaling resistance were investigated using a novel soybean oil sealer. The concrete mixtures were also evaluated within the LEED™ recycled materials criteria for selection based on economy and total contribution value. Considerations are included to assist designers in the selection of greener concrete mixtures for appropriate applications.

Use of Coarse Recycled Concrete Aggregate in Ternary Blended Portland Cement Concrete

2020 ◽  
Vol 2674 (10) ◽  
pp. 705-714
Author(s):  
Seth Wagner ◽  
Gabrielle Wickizer ◽  
Douglas Cleary ◽  
Gilson R. Lomboy ◽  
Danielle Kennedy ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Mechanical Performance ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Furnace Slag

The purposes of this study were to (a) investigate concrete pavement mixtures with recycled concrete aggregates using ternary blended cementitious binders, (b) measure the fresh and hardened properties of the concrete mixtures, and (c) assess the durability of concrete implementing the use of recycled coarse aggregates with ternary binders. Mixtures had recycled concrete aggregates at varying replacement rates. The binders were combinations of Portland cement, Class C and F fly ashes, and ground granulated blast furnace slag. At 50% replacement of virgin aggregates, some specimens showed comparable mechanical performance to the control mix. Performance is heavily tied to quality of recycled aggregates. The combined use of fly ash and blast furnace slag showed improvements in results for drying shrinkage, freeze–thaw durability, resistivity, and alkali–silica reaction mitigation.

Evaluation of strength of concrete on different initial exposure condition

2020 ◽  
Vol 13 ◽  
Author(s):  
Sri Ram Krishna Mishra ◽  
Pradeep Kumar Ghosh ◽  
Manoj Kulshreshtha
Keyword(s):  
Portland Cement ◽  
High Strength ◽  
Cementitious Materials ◽  
General Purpose ◽  
Supplementary Cementitious Materials ◽  
Exposure Condition ◽  
Portland Cement Concrete ◽  
Initial Exposure ◽  
Skilled Manpower ◽  
Standard Practices

Background: The previous studies have focused curing effect of mainly on high strength concrete, where strict supervision is maintained. This study is based upon general purpose concreting work for commercial and residential construction in absence of skilled manpower and supervision. Objective: The objective of this study is to establish a thumb rule to provide 7 days initial curing for maintaining quality for unsupervised concreting irrelevant to type of cement and grading. Methods: In this study concrete samples made with locally available commercial cements were cured for various initial exposure. Results: The results shows that concrete cured after a gap of 4 days from the time of de-moulding have given lowest strength as compared to concrete cured in standard practices i.e. where proper curing protocol had been followed. Conclusion: Initial curing is most important aspect of gaining desired strength. The findings after this study shows that curing affects the strength of concrete in variable grading. Initial curing has great importance for concrete with all types of Portland cement. Concrete with supplementary cementitious materials gives lowest strength initially but results higher strength after 28 days as compared to Portland cement.

Long-Term Performance of Recycled Portland Cement Concrete Pavement

1996 ◽  
Vol 1525 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Stephen A. Cross ◽  
Mohamed Nagib Abou-Zeid ◽  
John B. Wojakowski ◽  
Glenn A. Fager
Keyword(s):  
Portland Cement ◽  
Test Section ◽  
Load Transfer ◽  
Construction Materials ◽  
Concrete Pavement ◽  
Recycled Concrete ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Cement Concrete Pavement ◽  
Portland Cement Concrete Pavement

Over the past years there has been an increasing interest in recycling construction materials, particularly hot-mix asphalt (HMA) and portland cement concrete pavements (PCCP). To this end the Kansas Department of Transportation (KDOT) participated in Demonstration Project 47, Recycling Portland Cement Concrete Pavement, by recycling a moderately D-cracked concrete pavement and monitoring the performance over a 10-year period. The recycled concrete pavement (RCP) aggregate was evaluated in four test sections consisting of two control sections, one test section of portland cement-treated base (CTB) with RCP aggregate, and one test section using RCP aggregate in the PCCP and CTB. An HMA shoulder using RCP as coarse aggregate was also constructed. The test sections were monitored over a 10-year period for performance including faulting, roughness, load transfer, and friction measurements. Faulting, roughness, performance level, and joint distress measurements from KDOT's 1995 pavement condition survey were used to compare the performance of the recycled sections with PCCP of similar age and traffic in the same area of the state. All test sections performed well, with the CTB and PCCP sections with RCP aggregates showing slightly more distress.

scholarly journals The Influence of Discharge Time, Kind of Additive, and Kind of Aggregate on the Properties of Three-Stage Mixed Concrete

2018 ◽  
Vol 10 (11) ◽  
pp. 3862 ◽  
Author(s):  
Alena Sicakova ◽  
Karol Urban
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Discharge Time ◽  
Concrete Mixtures ◽  
Concrete Properties ◽  
Concrete Production ◽  
The Impact

Application of recycled aggregates (RA) for concrete production is limited due to their poor quality. While the environmental benefits of using the RA are well accepted, some unsolved problems prevent this type of material from wide application in structural concrete. The research and development of techniques which can minimize the adverse effect of RA on the concrete properties are highly requested. A specific mixing approach can also be helpful; here, mineral additives play a significant role for improvement of RA performance within the mixing process. However, delivery process can influence the homogeneity and uniformity of the concrete mixtures, resulting in negative effect on technical parameters. In this study, the impact of delivery time (0 min, 45 min, and 90 min) on the set of hardened concrete properties is presented while the three-stage mixing is used. Two kinds of additives—fly ash (FA) and recycled concrete powder (RCP)—were tested to coat the coarse fraction of recycled concrete aggregate (RCA) in the first step of mixing. For comparison, cement as coating material and natural aggregate instead the RCA were also used. The following parameters were tested after 28 days of setting and hardening: density, compressive strength, splitting tensile strength, water absorption capacity, and depth of penetration of water under pressure. Generally, 90 min of working with concrete mixtures left no significantly negative influence on tested characteristics. Based on ANOVA results, with prolonged discharge time, the changes in composition of the mixtures become less important for compressive strength, density, and water absorption.

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