Engineering Commons^™

The Effects Of Curing Temperature On The Hydration Kinetics Of Plain And Fly Ash Pastes And Compressive Strength Of Corresponding Mortars With And Without Nano-Tio2 Addition., Dan Huang, Mirian Velay-Lizancos, Jan Olek

International Conference on Durability of Concrete Structures

Incorporation of fly ash in cementitious systems containing ordinary portland cement (OPC) increases their long-term strength and durability. However, replacement of cement by fly ash also reduces the heat of hydration of such systems and reduces early-age strength development. The reduced rate of strength development can increase the risk of durability problems, e.g. scaling, in cases when young concrete is exposed to low temperatures and deicing chemicals. This study investigated the potential of nano-titanium dioxide (nano-TiO₂) particles to modify the hydration kinetics of fly ash pastes and compressive strength development of corresponding mortars cured under low (4°C) and …

Strength Of Reinforced Concrete Beams With High-Strength Steel, Brian C. Rogers, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

Structures are commonly made of reinforced concrete, which is a composite material made of concrete and steel reinforcement. Using high-strength steel, with yield stress larger than 100 ksi, could help reduce the quantity of steel required in structural members, thus reducing costs and improving constructability. The hypothesis being tested is that smaller quantities of high-strength steel reinforcement (HSSR) can be used in place of conventional steel in reinforced concrete beams while maintaining similar strength and deformation at failure. Two reinforced concrete beams with two different types of longitudinal steel reinforcement were constructed. The beams were 18 in. wide, 30 in. …

Study Of Water Permeability Of Lightweight Concrete, Xiaoxiao Xu, Haibin Yang, Hongzhi Cui, Zitao Lin, Tommy Yiu Lo

International Conference on Durability of Concrete Structures

The relationship between water permeability and different levels of the tested layers from the top surface to the bottom surface of the lightweight concrete specimens is determined in this study. It is beneficial to develop the design criteria for a durable lightweight concrete. The water permeability coefficient K of the samples was determined by water permeability test using GWT. It is found that the water permeability coefficient K of the three layers in each set of samples tends to decrease as the level of the tested from the top surface increase. Larger Rebound Number and higher density in the bottom …

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

Development Of Internally Cured Concrete For Increased Service Life, John Schlitter, Ryan Henkensiefken, Javier Castro, Kambiz Raoufi, Jason Weiss, Tommy Nantung

JTRP Technical Reports

Higher strength, lower water to cement ratio (w/c) concrete has been advocated over the last two decades due to its increased strength and reduced permeability. The lower w/c of these concretes makes them susceptible to autogenous shrinkage. This autogenous shrinkage can be significant and can be a contributing factor to early age cracking. Internal curing was investigated as a potential method to improve the durability of concrete pavements and bridge decks. Prewetted lightweight aggregate was used to supply water to the hydrating cement paste. This additional water can counteract the hindered strength development, suspended hydration, autogenous shrinkage, and early age …

Stiffness Of Hot-Mix Asphalt, Terhi K. Pellinen, Shangzhi Xiao

JTRP Technical Reports

This research was initiated from a need to evaluate marginal mixtures that do not meet the Superpave mix design criteria for the air voids content requirements for the construction of hot mix asphalt pavements. The developed criteria is comprised of the base criteria derived from test data of as-placed field cores normalized to 7.5% air voids content, which provides the minimum stiffness and strength requirements for a mixture as a function of the traffic level. The stiffness of pavement cores is measured using Simple Shear Tester to obtain shear stiffness |G*| of mix and strength is measured using indirect tensile …

Stabilization And Improvement Of Organic Soils, Joonho Hwang, Aaron Humphrey, Antonio Bobet, Maria Caterina Santagata

JTRP Technical Reports

Peats and organic soils in general pose significant problems to geotechnical engineers due to their low strength, high compressibility and elevated creep. The research performed addressed one soil improving technique, deep soil mixing, that has been widely used for treating soft clays, but that especially in the US has found limited use in presence of organic soils. The work performed made use primarily of one soil sampled on Lindberg Road (LR) in West Lafayette, IN characterized by LOI= 45-52%, LL= 327%, PL= 162%, LLoven dried/LLnon-dried = 0.31, Gs = 2.05-2.12, fiber content ~2.29%, clay fraction = 40.6%. In addition, a …

Influence Of Curing Conditions On Strength Properties And Maturity Development Of Concrete, Scott Andrew Newbolds, Jan Olek

JTRP Technical Reports

In this study, the results of both laboratory studies and a field study, conducted to evaluate the effects of different curing conditions on the strength properties and maturity development of pavement concrete, are presented. Further, a laboratory study was performed to evaluate the maturity concept in relation to the degree of hydration of cement. Concrete specimens, beams and cylinders, were prepared in the field study. The specimens in the field were cured in one of four curing conditions: lime bath, sandpit, air, or by temperature match curing. Specimens were tested for flexural strength and compressive strength, respectively. The temperature of …

Performance Of Bridge Decks And Girders With Lightweight Aggregate Concrete, V. 2 Of 2, J. A. Ramirez, J. Olek, Eric Joseph Rolle, Brian Joseph Malone

JTRP Technical Reports

Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction.

The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of hardened concrete (compressive strength, tensile strength, flexural strength, static and dynamic modulus of elasticity, Poisson’s Ratio, and temperature development), and durability related parameters (air void distribution, freeze-that …

Performance Of Bridge Decks And Girders With Lightweight Aggregate Concrete, J. A. Ramirez, J. Olek, Eric Joseph Rolle, Brian J. Manlone

JTRP Technical Reports

Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of hardened concrete (compressive strength, tensile strength, flexural strength, static and dynamic modulus of elasticity, Poisson’s Ratio, and temperature development), and durability related parameters (air void distribution, freeze-thaw …

Stay-In-Place Deck Panels - Horizontal Shear Strength Of Bridge Deck Panels - Part 2, Phani Kumar Nukala, J. A. Ramirez, Robert H. Lee, Menashi D. Cohen

JTRP Technical Reports

One of the most economic methods of bridge deck construction consists of prestressed concrete deck panels used in stay-in-place forms in conjunction with the cast-in-place concrete topping instead of the traditional monolithic roadway deck slabs. The performance of this type of deck as a composite unit is only possible if the horizontal shear stress resulting from bending of the deck if effectively transferred across the interface of the two elements. It is assumed that horizontal shear stresses are transmitted across the interface due to bond between the precast panel and cast-in-place concrete acting in conjunction with the horizontal shear connectors …