skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Reinforced, Nailable Rubber Concrete with Strength and Withdrawal Properties Similar to Lumber
The inclusion of rubber in concrete has been suggested and used in recent research. However, the reason for the inclusion of rubber into concrete is typically the need to offset the carbon footprint of concrete and other environmental concerns. The research presented here indicates that the inclusion of rubber into concrete allows for the concrete to accept fasteners and withstand withdrawal, or pullout, of the fasteners, similar to the function of wood. We refer to this as making the concrete “nailable”, in that the concrete can be nailed together either by hand or with tools designed to be used with wood. While other methods have been used to make concrete nailable, this method is novel as no known research exists indicating that there exists a rubber concrete mix that provides similar withdrawal strength as wood. Testing indicates that the concrete can be produced at a low cost due to the inclusion of the low-cost rubber infill with reinforcement wire. The result is a reinforced concrete with an allowable load that is 13% greater than in spruce and a withdrawal force up to 25% greater than the maximum in spruce. The intended function of this material is replacement of treated lumber. The proposed rubber concrete, which is a reinforced concrete, is anticipated to have a service life of 50–100 years, while treated lumber decks in the Southeastern United States have been surveyed to have an average life of only 10 years due to environmental degradation. This leads us to conclude that if a deck were to be constructed of this nailable rubber concrete, it would last approximately five times longer in a temperate environment, such as the Southeastern United States. This improvement can be provided at a relatively low cost while providing an alternative that both prevents the use of arsenic- and copper-containing compounds used in treated lumber and provides an additional recycling method for tires.  more » « less
Award ID(s):
2226952
PAR ID:
10486964
Author(s) / Creator(s):
;
Publisher / Repository:
MDPI
Date Published:
Journal Name:
Journal of Composites Science
Volume:
7
Issue:
10
ISSN:
2504-477X
Page Range / eLocation ID:
405
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, 12th International Conference on Wood Adhesives)
    Hunt, Christopher; Jakes, Joseph; Grigsby, Warren; Konnerth, Johannes; Herwijnen, Erik van; Yan, Ning (Ed.)
    Mass timber construction is rapidly growing in North America, given its versatility and performance. In addition, wood has a high strength to weight ratio and low environmental impact in contrast with other construction materials. Nevertheless, durability is a significant concern that needs to be addressed for the advancement of mass timber construction. Extreme care is required to protect members from exposure to high moisture environments while ensuring long-term durability. This project thus focuses on improvements of wood's longevity by combating two main issues: dimensional stability and decay resistance to biological organisms. At the same time, a sustainable approach is considered while utilizing small-diameter logs, which optimizes forest industry products. This is all achieved with the fabrication of Cross Laminated Strand-Veneer-Lumber (CLSVL) out of thermally modified wood strands. State-of-the-art concepts and technologies are implemented in the treatment process, fabrication, and assessment of the material. At first, wood strands are treated at different temperatures to understand its implications. A look at wettability, water sorption, and wood structure is used for this analysis. Furthermore, a series of macro-level mechanical benchmark tests in thin plies are conducted, such as internal bonding, bending, and tension. Later, accelerated decay tests are done to assess the improvement of wood's resistance to rot fungi. Finally, these analyses are used to systematically optimize the thermal treatment to obtain the best performing material to be used in the fabrication of mass timber as CLSVL. 
    more » « less
  2. ; ; ; ; (, Proceedings of the National Academy of Sciences)
    Afforestation and reforestation (AR) on marginal land are nature-based solutions to climate change. There is a gap in understanding the climate mitigation potential of protection and commercial AR with different combinations of forest plantation management and wood utilization pathways. Here, we fill the gap using a dynamic, multiscale life cycle assessment to estimate one-century greenhouse gas (GHG) mitigation delivered by (both traditional and innovative) commercial and protection AR with different planting density and thinning regimes on marginal land in the southeastern United States. We found that innovative commercial AR generally mitigates more GHGs across 100 y (3.73 to 4.15 Giga tonnes of CO 2 equivalent (Gt CO 2 e)) through cross-laminated timber (CLT) and biochar than protection AR (3.35 to 3.69 Gt CO 2 e) and commercial AR with traditional lumber production (3.17 to 3.51 Gt CO 2 e), especially in moderately cooler and dryer regions in this study with higher forest carbon yield, soil clay content, and CLT substitution. In a shorter timeframe (≤50 y), protection AR is likely to deliver higher GHG mitigation. On average, for the same wood product, low-density plantations without thinning and high-density plantations with thinning mitigate more life cycle GHGs and result in higher carbon stock than that of low-density with thinning plantations. Commercial AR increases the carbon stock of standing plantations, wood products, and biochar, but the increases have uneven spatial distributions. Georgia (0.38 Gt C), Alabama (0.28 Gt C), and North Carolina (0.13 Gt C) have the largest carbon stock increases that can be prioritized for innovative commercial AR projects on marginal land. 
    more » « less
  3. ; ; ; ; (, 18th International Conference on Non-Conventional Materials and Technologies (18NOCMAT))
    The use of screw connections in full-culm bamboo is often assumed to be limited, primarily due to the propensity for splitting of the culm. This study demonstrates that small diameter screws can be used effectively in full-culm bamboo. The study explores the withdrawal capacity of candidate screw types in order to identify those that may be used to achieve a high capacity while mitigating splitting failures. Twelve screw types of three standard sizes, ranging from hardwood screws, self-tapping wood screws and concrete anchors, are tested in conditions of both pre-drilled and self-tapping installation procedures. All tests are conducted on samples of P. edulis (Moso) having culm wall thickness on the order of 7 mm. The results of this study are intended to inform the applications for which screw connection to bamboo are viable. 
    more » « less
  4. ; ; ; ; (, 18th International Conference on Non-Conventional Materials and Technologies (18NOCMAT))
    The use of screw connections in full-culm bamboo is often assumed to be limited, primarily due to the propensity for splitting of the culm. This study demonstrates that small diameter screws can be used effectively in full-culm bamboo. The study explores the withdrawal capacity of candidate screw types in order to identify those that may be used to achieve a high capacity while mitigating splitting failures. Twelve screw types of three standard sizes, ranging from hardwood screws, self-tapping wood screws and concrete anchors, are tested in conditions of both pre-drilled and self-tapping installation procedures. All tests are conducted on samples of P. edulis (Moso) having culm wall thickness on the order of 7 mm. The results of this study are intended to inform the applications for which screw connection to bamboo are viable. 
    more » « less
  5. ; ; (, Materials)
    There are ongoing research efforts directed at addressing strength limitations of compressed earth blocks (CEB) that inhibit their deployment for structural applications, particularly in areas where masonry systems are regularly subjected to lateral loads from high winds. In this paper, the authors focus specifically on the extent to which polypropylene (PP) fibers can be used to enhance the flexural performance of CEB. Cementitious matrices used for CEB production exhibit low tensile and flexural strength (brittle) properties. This work investigates plain (unreinforced) and fiber-reinforced specimens (short flexural beams) with fiber mass content of 0.2, 0.4, 0.6, 0.8, and 1.0% and ordinary Portland cement (OPC) content of 8%. The influence of the inclusion of fiber was based on tests conducted using the Standard Test Method for Flexural Performance of Fiber-Reinforced Concrete (ASTM C1609). Material properties that were quantified included first-peak strength, peak strength, equivalent flexural strength, residual strength, and flexural toughness. There was an observed improvement in the performance of the soil-fiber matrixes based on these results of these tests. It was also observed that when the fiber content exceeded 0.6% and above, specimens exhibited a deflection- hardening behavior; an indication of improvement in ductility. An equivalent flexural strength predictive model is proposed. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email