Enhancing Resiliency and Delivery of Bridge Elements using Ultra-High Performance Concrete as Formwork

2019 ◽  
Vol 2673 (5) ◽  
pp. 443-453 ◽  
Author(s):  
Atorod Azizinamini ◽  
Sheharyar Rehmat ◽  
Amir Sadeghnejad
Keyword(s):  
Test Specimen ◽  
High Performance ◽  
High Performance Concrete ◽  
Numerical Study ◽  
Concrete Specimen ◽  
Point Load ◽  
Ultra High Performance Concrete ◽  
Normal Concrete ◽  
Element Analysis ◽  
Normal Strength

A feasibility study of the use of ultra-high performance concrete (UHPC) shell as a formwork is presented. The core concept of the research, developed by the first author, is prefabrication of UHPC shell which acts as a stay-in-place formwork. In the proposed approach, after transporting the UHPC shell to site, the construction of structural elements is completed by placing reinforcing cage inside the UHPC shell and post-pouring with normal concrete. The superior properties of UHPC provide excellent means to enhance the service life of bridge elements, while eliminating the need for assembling or stripping of formwork. As a proof of concept, a combination of experimental and numerical studies was conducted, results of which are reported here. Before conducting experimental work, numerical study in the form of finite element analysis was carried out to investigate performance of shell during placement of the normal concrete. To provide a baseline comparison between UHPC shell formwork and conventional methods, two test specimens were constructed and tested under three-point load setup. The shell test specimen demonstrated flexural strength, 14% greater than an equivalent normal strength concrete specimen. The UHPC shell test specimen failure occurred by debonding of shell at the interface and development of a large crack in the shell. The shell test specimen exhibited improved levels of ductility before failure. The preliminary analysis demonstrated that the idea is feasible and useful for accelerated bridge construction applications.

scholarly journals Experimental and Numerical Study of Nano-Silica Additions on the Local Bond of Ultra-High Performance Concrete and Steel Reinforcing Bar

2018 ◽  
Vol 3 (12) ◽  
pp. 1339 ◽  
Author(s):  
Ahad Amini Pishro ◽  
Xiong Feng
Keyword(s):  
Numerical Analysis ◽  
High Performance ◽  
High Performance Concrete ◽  
Numerical Study ◽  
Concrete Specimen ◽  
Bond Stress ◽  
Nano Silica ◽  
Ultra High Performance Concrete ◽  
Reinforcing Bar ◽  
Micro Silica

Micro-silica is widely used as an additive to cement in producing high performance concrete. This matter is used to enhance the strength and efficiency of concrete. Recently, due to the development of advanced nano-technology, nano-silica has been produced with particle sizes smaller than micro-silica and higher pozzolanic activity. Studies show that addition of nano-silica into cement-based materials improves their mechanical properties. Considering the unique characteristics of nano-silica, it seems that this material can be used in ultra-high performance concrete (UHPC). Therefore, further studies are needed on how the local bond and bond stress of steel reinforcing bar and UHPC containing nano-silica would be effected. In the present study, after preparing the mix designs and proposed specimens, the effects of various parameters on the local bond of steel reinforcing bars and UHPC containing nano-silica were examined by pullout experiments. In this research, we have numerically investigated the bond strength using numerical methods and calibration of the ABAQUS results in addition to its experimental study of ultra-high performance concrete and steel reinforcement. In numerical analysis, the concrete damage plasticity method was used to simulate the nonlinear behavior of concrete and its strain softness. Comparing between numerical and experimental analysis results shows that numerical analysis with high precision can predict the bond stress, bond load, and concrete specimen fracture mode.

scholarly journals Determination of Axial Capacity for Enhanced Normal and Ultra - High Performance Concrete Columns

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarmad Shafeeq Abdulqader ◽  
Asmaa Ali Ahmed ◽  
Nawfal Shihab Ahmed
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Peak Load ◽  
Concrete Cover ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
Compression Load ◽  
Axial Capacity ◽  
Load Carrying ◽  
Normal Strength

Abstract Concrete Technology has been developing for more than a century. One of the most exceptional achievements in concrete technology is the evolving of Ultra-High Performance Concrete (UHPC) which has been a research focus in a wide applications diversity. In this paper, an experimental work has been carried out for investigating the transverse and longitudinal reinforcements’ variation influence on the axial capacity of UHPC columns. Eight columns (five UHPC columns and three Normal Strength Concrete (NSC) columns) have been poured and tested under a concentric axial compression load till a failure is reached. Then, the results are reported herein. The experimental results show that UHPC columns failed in a controlled manner and no concrete chips or a concrete cover spalling are observed. Also, the longitudinal reinforcements have not buckled away beyond the peak load because of the presence of the reinforcing steel fibers in UHPC. Correspondingly, the steel ties spacing proportionally affects the load carrying capacity of columns as presented hereinafter.

scholarly journals Shrinkage in Ultra-High Performance Concrete Overlays on Concrete Bridge Decks

2019 ◽  
Vol 271 ◽  
pp. 07008
Author(s):  
William Toledo ◽  
Leticia Davila ◽  
Ahmed Al-Basha ◽  
Craig Newtson ◽  
Brad Weldon
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks ◽  
Plastic State ◽  
Early Age ◽  
Concrete Bridge ◽  
Ultra High Performance Concrete ◽  
Concrete Overlays ◽  
Concrete Bridge Decks ◽  
Normal Strength

This paper investigates the shrinkage and thermal effects of an ultra-high performance concrete (UHPC) mixture proposed for use as an overlay material for concrete bridge decks. In this study, early-age and longer-term shrinkage tests were performed on the locally produced UHPC. Thermal and shrinkage effects in normal strength concrete slabs overlaid with UHPC were also observed. Early-age shrinkage testing showed that approximately 55% of the strain occurred in the plastic state and may not contribute to bond stresses since the elastic modulus of the UHPC should be small at such early ages. Thickness of the substrate and amount of reinforcing steel were important factors for shrinkage in the slabs. The thickest slab experienced greater shrinkage than thinner slabs. Comparing this slab to a thinner slab with the same reinforcement indicated that reinforcement ratio is more important than the area of steel.

The Determination of Frost Resistance on Ultra High Performance Concrete

2014 ◽  
Vol 1025-1026 ◽  
pp. 1005-1009 ◽  
Author(s):  
Michaela Kostelecká ◽  
Jiří Kolísko
Keyword(s):  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Silica Sand ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
Normal Concrete ◽  
Different Types ◽  
High Range

The ultra high performance concrete (UHPC) has very special properties that are expressively different of normal concrete. Due to its high compression strength greater than 150 MPa, tensile strength greater than 20 MPa and improved durability, these represent significant advances in concrete technology. These materials include Portland cement, silica fume, quartz flour, fine silica sand, high-range water-reducer, water and either steel or organic fibres. Depending on the type of fibres used can influence the compressive strength. The article describes the tests of frost resistance on UHPC plates with different types of textiles armatures. The aim of the testing is describe influence of textiles armatures in UHPC matrix in extreme conditions.

scholarly journals An Auto-Calibrating Semi-Adiabatic Calorimetric Methodology for Strength Prediction and Quality Control of Ordinary and Ultra-High-Performance Concretes

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 96
Author(s):  
Marco Viviani ◽  
Luca Lanzoni ◽  
Vincenzo Savino ◽  
Angelo Marcello Tarantino
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Ultra High Performance Concrete ◽  
Structural Element ◽  
Construction Operations ◽  
Equivalent Time ◽  
Normal Strength ◽  
Good Agreement

A timely knowledge of concrete and ultra-high-performance concrete (UHPC) strength is possible through the so-called strength-equivalent time (Et) curves. A timely knowledge of concrete strength is useful, for instance, to precisely determine when the shores of a hardening structural element can be safely removed. At the present time, the preparation of the strength-Et curves requires time-consuming and labor-intensive testing prior to the beginning of construction operations. This paper proposes an innovative method to derive the strength-Et and total heat-Et curves for both normal strength and UHPC. Results confirmed that the proposed method is fast, inexpensive, self-calibrating, accurate and can detect any variation of the concrete mix proportions or components quality. In addition, the quality of predictions of strength–maturity curves can be constantly improved as the specimens’ population increases. Finally, results obtained with the proposed method were compared with those obtained using standard methods, showing a good agreement.

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