Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 14 of 14 for “"Autogenous Shrinkage"”.
-
Drinking Water Treatment Waste as an Alternative for Internal Curing and Cement Replacement in Concrete
… through several mechanisms broadly grouped into autogenous and drying shrinkage. These mechanisms cause cracks which become high permeability routes for water and aggressive ion movement, such as chlorides to reinforcing steel. Drying shrinkage can be controlled by appropriate curing methods, …
-
Design and performance of cost-effective ultra high performance concrete for bridge deck overlays
… was examined. The efficiency of various shrinkage mitigation approaches in reducing autogenous and drying shrinkage of optimized UHPC mixtures was evaluated. This included the use of CaO-based and MgO-based expansive agents, shrinkage-reducing admixture, and pre-saturated lightweight …
-
Early age creep and shrinkage of emerging concrete materials
… components of volume change are external drying shrinkage, autogenous shrinkage, and thermal dilation. When concrete is restrained, tensile stress develops due to shrinkage and increases the probability of cracking. Early age properties, such as tensile creep, are not well understood and the …
-
The Role of Reactive MgO as an Expansive Additive in the Shrinkage Reduction of Concrete
… mainly dam construction in China, for thermal shrinkage reduction since the 1970’s. At ~4% addition to the cement by weight, it is much simpler than conventional shrinkage measures and in particular, reduces the quantity of crack control reinforcement used. The mechanism is similar to …
-
Reactive MgO and Self-healing Microcapsules for Enhanced Well Cement Performance
… problems originate from oil well cement shrinkage and shrinkage-induced cracking, as well as cracking induced by other external stresses. The addition of expansive additives is a commonly used way to compensate for shrinkage. Compared to conventional ettringite-based and CaO-based …
-
Measuring and Modeling the Time-Dependent Response of Cementitious Materials to Internal Stresses
Recent advances in shrinkage modeling have worked toward modeling autogenous and drying shrinkage as mechanical responses to internally applied stresses. In this thesis, previous modeling work is extended such that autogenous shrinkage of cement paste is considered as a viscoelastic response to …
-
SYNERGISTIC EFFECT OF SHRINKAGE MITIGATING STRATEGIES ON PERFORMANCE OF FIBER-REINFORCED CEMENTITIOUS COMPOSITES
<p>"The advantages of using shrinkage mitigating strategies to reduce shrinkage and mitigate cracking of concrete is well documented. However, the benefits and drawbacks of employing multiple strategies have not been explored. The main objective of this study is to provide insights into the …
-
The Development of Sustainable Internal Curing Agents Using Natural Hollow Fibres
… by the holes and defects in the fibre walls. The shrinkage, mechanical strength, and microstructural development of cementitious mixes after incorporating pre-treated MW fibres were examined in the final phase. The internal curing role of the pre-treated MW fibres proved effective in reducing …
-
Design and performance of cost-effective ultra-high performance concrete for prefabricated elements
… 25% to increase mechanical properties and reduce shrinkage; (b) at steel fiber content of 2%, the optimal plastic viscosity of the suspending mortar was 53 ± 3 Pa·s to secure favorable fiber distribution and enhance flexural properties of the UHPC; (c) through use of hybrid steel fibers, the …
-
Ultrasonic wave reflection measurements on stiffening and setting of cement paste
… of partial debonding, most likely resulting from autogenous shrinkage of the paste.
-
Shrinkage of concrete using porous aggregates
… There are several types of volume changes, but shrinkage is the type of volume change which is often responsible for cracking of the concrete. Shrinkage can be categorized due to several different mechanisms which cause shrinkage. The main types of shrinkage are plastic shrinkage, chemical …
-
Evaluating shrinkage of fly ash - slag geopolymers
… of geopolymers when used in field. Since shrinkage causes volume change, any volume change after the binder has stiffened will cause stresses to develop and this will cause cracks and reduction in the load carrying capacity of the mix. The study was performed on a user-friendly geopolymer …
-
Ultrasonic wave reflection measurements on self-compacting pastes and concretes
… Partial debonding is probably caused by autogenous shrinkage at final set, and was controlled and limited by water. The extent of partial debonding was higher with the transducers placed on the side as opposed to the bottom, and the S-wave transducer seemed to promote debonding in the …
-
Understanding effects of pre-soaked lightweight aggregate on volume stability of mortar and concrete mixtures
Shrinkage cracking is a predominant deterioration mechanism greatly affecting the durability and integrity of concrete structures. This is especially the case for concrete bridge decks due to the large surface-to-volume ratio of these types of structures, which results in a high rate of moisture …