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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Behaviour of cementitious subbase layers in bitumen base road structures

De Beer, Morris 04 August 2009 (has links)
The process of designing cementitious layers (weakly and strongly cemented) against fatigue distress in road structures is well accepted. Research and field investigations with the aid of the Heavy Vehicle Simulator (HVS) revealed, however, that almost all weakly cemented subbase layers undergo non-traffic and traffic¬associated cracking and eventually degradation of the cemented material into a granular state (post-cracked phase). It is therefore very important to analyse these layers in the post-cracked phase and to incorporate the results of this analysis in the design, for both new and rehabilitation designs. The investigations revealed that the rate of degradation of these materials is largely dependent on traffic loading and the moisture conditions within the pavement layers. The purpose of this study is to investigate the behaviour of weakly cemented subbase layers in road structures mainly under a bitumen base between 90 mm and 140 mm thick. This behaviour includes both pre-cracked and post-cracked phases. It is shown that the fatigue life of bitumen base layers is mainly governed by the condition of the weakly cemented subbase layers. In Chapter 1 a brief historical review is given of the development of fatigue distress criteria of the cementitious layers. It is shown that the maximum horizontal tensile strain at the bottom of these layers is the main distress criterion in the pre-cracked phase. Unconfined compressive strength and durability requirements are also discussed. Some aspects of the current design methods are outlined in Chapter 2. The concept of equivalent granular states in the post-¬cracked phase of cementitious layers was derived from HVS test findings. However, before this document no behavioural prediction models were available to quantify accurately the post-cracked state of these layers. The actual mechanisms of distress were also not clear. In Chapter 3, a detailed investigations and analysis of ten dif¬ferent HVS tests at four different sites in Natal are discussed. The purpose of the analysis, is firstly to illustrate the powerful method of full-scale accelerated HVS-type testing and secondly to indicate the importance of the upper subbase layer, the initial condition of the in-situ structure, the importance of water condi¬tions within the pavement structure, and finally the different states of behaviour of this type of road structure, including predictions of future behaviour based on linear elastic theory. The characteristics of the weakly cemented upper subbase layer are shown to be of paramount importance in the final behaviour of these structures. In Chapter 4 a method of analysing the behaviour of mainly weakly cemented layers in the post-cracked phase is proposed. This method arises from the HVS testing discussed in Chapter 3, and may be regarded as the most important improvement on the current method discussed in Chapter 2. The analysis incorporates the determination of the effective elastic moduli of weakly cemented subbase layers, including both the wet and the dry periods during the structural design period of these layers. In Chapter 5 the effect of relatively weak interlayers within asphalt base structures is discussed and evaluated. The analysis incorporates the relative position and thickness of the inter layer during both wet (low modulus) and dry (high modulus) conditions. A summary and detailed discussion, together with recommendations for future research, are given in Chapter 6. The need for the incorpo¬ration of durability (erodibility) criteria for weakly cemented materials is also discussed. More research should be done on the effects of accelerated curing compared with normal curing methods. This investigation includes aspects of soil-lime-cement reactions together with delayed compaction techniques to reduce shrinkage cracking. The need for better quality control as well as improved construction techniques for weakly cemented materials is also discussed. This thesis also contains two appendices. In the first of these detailed photographic records of the different HVS tests and performances are given. In the second appendix an example of an input computer program to plot the three dimensional behavioural model is given. / Dissertation (MEng)--University of Pretoria, 2009. / Civil Engineering / unrestricted
2

Návrh řešení MÚK dálnice D1 se silnicí I/23 a II/602 u Kývalky / The proposed solution MÚK D1 motorway with road I/23 and II/602 u Kývalka

Březina, Michal January 2015 (has links)
The master´s thesis focuses on modification of existing interchange Kývalka on D1 motorway. The purpose of this thesis is to design optimal solution of junction of roads I/23 and II/602 with D1 motorway connecting all directions, considering transport capacity a safety. The another part of the thesis is widening motorway D1 to six lane arrangement with one lane for slow vehicles. At first, several possible designs were suggested of which two were chosen for further elaboration as a search study. In the end, thesis contains the comparison of two chosen designs.
3

Studie mimoúrovňové křižovatky R46 / The study interchanges R46

Dostál, Jan January 2016 (has links)
The master´s thesis focuses on design interchange on R46 highway. The purpose of this thesis is to design optimal solution of transport capacity and safety. The another part of the thesis is solution of connecting on roads II/433 and III/37766. This solution is part of bypass plan, by city plan of Prostějov.
4

Studie mimoúrovňové křižovatky MÚK Brno Východ / Technical study of the interchange Brno - East

Marušák, Lubomír January 2018 (has links)
This thesis deals with the modification of the interchange of motorway D1 in Brno – east (km 203). It’s aim to design an optimal solution for omnidirectional connection on the road I/50. Currently it has the shape of a letter Y which allows only a two-way ride. Further, the aim is to propose the connection of the road II/430 to the road junctions. Part of this thesis is proposal to extend the motorway to a six-lane in the place of interchange due to capacity utilization. For this thesis was chosen one from four concepts of the junction within the scope of the study. The work is complemented by a tradic survey on the current arrangement which was carried out using statistical radars.
5

Příprava a realizace Protonového terapeutického centra v Praze / Implementation of Proton Therapy Center in Prague

Halanič, Daniel January 2019 (has links)
The diploma thesis deals with the construction technological project of carcass SO – 001 Proton Therapy Center. The thesis is focused on part B (gantry) of hospital building Proton Therapy Center in Bulovka Hospital area in Prague. The thesis is being processed vertical and horizontal massive monolithic reinforced concrete skeleton realization. The thesis is report, budget, time schedule, technological specification, design of site equipment, design of machinery, design of road construction and next text and drawing documentation processed by assignment of diploma thesis.
6

Stavebně technologický projekt přípravy a realizace administrativní budovy firmy TREFAL, spol. s r.o. / Construction project for Implementation of Administrative Building of TREFAL, spol. s r.o.

Bočková, Andrea January 2020 (has links)
The aim of this thesis is the development project of the firm TREFAL, Spol. s.r.o. The object SOO2 - Administrative building - that is a constituent of the area of TREFAL, Spol. s.r.o. is discussed topic of this thesis. The main focus is the construction development of the monolithic supporting construction objects. The thesis further depicts and investigates accompanying and overall technical report, an implementation study of the main technological stages, situational designs, a solution of the broader traffic relations including a proposal for the supplementation of the construction development, BOZP plan, budget and timeline, a proposal for the new local communication and following textual and design documentation according to the thesis assignments.
7

Asfaltocementový beton / Open-graded asphalt concrete filled with a special cement grout

Hruška, Lukáš January 2012 (has links)
Aim of this thesis is the usage of the open-graded asphalt concrete filled with a special cement grout in the road structures. Thesis defines the main concrete properties and explains related legislation and norms that apply. In addition, laboratory design of asfalt mixtures and a tree kind mortal filler and possibilities of mortal filler pigmentation are dealth with. Finally, thesis evaluates the results from various laboratory tests that were performed on the specimens made from final mixtures.

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