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The mechanical properties of cement stabilized minestoneMcMahon, P. H. January 1985 (has links)
No description available.
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Rheological and engineering properties of asphaltic paving materials with polymer modified and conventional bindersDavies, E. January 1993 (has links)
No description available.
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Shrinkage characterisation, behavioural properties and durability of cement-stabilised pavement materialsMbaraga, Alex Ndiku 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: With the depletion of high quality conventional materials for road pavements, the
consideration of cement stabilisation for sub-base and base layer materials often provide a
feasible solution to the road industry. Like all pavement material types, the design inputs
should be determined using reliable test methods, which provide a good indication of the
property of materials. Any evaluation should provide a better understanding of the
engineering and behavioural properties of the materials. This should form the basis for
ascertaining their suitability for use in the pavement structure. However, the road industry is
dependent on strength testing of cement-stabilised materials as a means to ascertain
material suitability for use. Strength alone does not offer reliable insight regarding the
performance and durability of the stabilised layer. This is because a cement-stabilised layer
may be very stiff but not strong enough to withstand the loading and endure adverse
environmental conditions. Similarly, the stabilised layer may be prone to cracking emanating
from shrinkage, which leads to performance and durability related distresses.
A stabilised sub-base and base of the pavement structure experiences tensile stresses and
strains under traffic loading. At laboratory level, the flexural beam test simulates to an
acceptable degree the mode of stress to strain to which the pavement layer experiences.
However, the test lacks a standard test protocol. This leads to inconsistencies while
evaluating the same material type. Due to this fact, the formulation of a standard laboratory
test procedure is necessary.
Shrinkage cracking is one of the major causes of pavement failure. The manifestation of
wide cracks leads to performance related distresses. Cracks provide zones for the infiltration
of water into the underlying layers, an aspect that results in further deterioration of the
pavement structure. However, the evaluation of shrinkage at laboratory level is not usually
undertaken. Disregarding shrinkage evaluation stems from the fact that a number of
guidelines consider it as a natural material characteristic. The road industry frequently
depends on the use of low cement contents among other techniques as a means to mitigate
shrinkage cracking in cement-stabilised layers. The selection of a mitigation measure usually
lacks reliable data concerning the material’s shrinkage potential. Because of this, the
requirement to evaluate shrinkage at laboratory level as part of a material property measure
provides a good indication regarding the quality of material.
Nanotechnology products such as the Nanotterra Soil® a polymer cement additive are
purported to mitigate shrinkage cracking in cement-stabilised layers. However, their
suitability for use remains unspecified and dependent on the stakeholders. With the
development of a shrinkage method, the evaluation of shrinkage reducing products can be
undertaken.
This research proposes a flexural beam test protocol for cement-stabilised materials,
comprising of a span-depth ratio of nine or greater as fitting to provide a reliable measure of
the material’s flexural strength and elastic modulus. The developed shrinkage test method
provides a good repeatability and is user friendly. The test provides a good indication of the
shrinkage criteria of ferricrete and hornfels with and without the polymer. The efficacy of
the polymer is dependent on the cement content in the mix and the type and quality of the
material. The research provides insight pertaining to the characterisation of shrinkage, behavioural properties, and durability of cement-stabilised materials. Analysis of the
shrinkage crack pattern reveals that use of the polymer lessens the development of tensile
stress in a cement-stabilised layer. Equally, the application of the low cement contents for
stabilisation may not result in cracking of the stabilised layer. This research contributes to a
better understanding of cement-stabilised materials. / AFRIKAANSE OPSOMMING: Namate hoë kwaliteit konvensionele materiale uitgeput raak, word sementstabilisasie van
stutlaag en kroonlaag materiale al hoe meer oorweeg en is dit ʼn geskikte oplossing vir die
padbou-nywerheid. Soos vir alle padboumateriale moet die ontwerpeienskappe bepaal word
deur middel van betroubare toetsmetodes wat ʼn goeie aanduiding van die materiaal se
eienskappe sal gee. Enige evaluering moet ʼn beter insae in die materiaal se
ingenieurseienskappe en gedrag oplewer. Dit moet dan die basis vorm om die materiaal se
gebruik in ʼn padstruktuur te evalueer. Die padbou-nywerheidmaak grootliks staat op die
toetsing van skuifsterkte van sementgestabiliseerde materiaal om die geskiktheid daarvan
vir gebruik te bepaal. Sterkte op sigself lewer egter nie ʼn betroubare maatstaf van die
materiaal se gedrag en duursaamheid nie. Dit is aangesien ʼn sementgestabiliseerde laag
baie solied mag wees maar nogtans nie sterk genoeg om belasting te weerstaan en bestand
teen omgewingstoestande te wees nie. Net so mag ʼn gestabiliseerde laag vatbaar vir
kraakvorming as gevolg van krimping wees en dit kan lei tot duursaamheid-verwante en
werkverwante skade.
ʼn Gestabiliseerde stutlaag en kroonlaag in die plaveiselstruktuur is onderhewig aan
trekspannings en vervormings as gevolg van verkeerslaste. Op laboratoriumvlak boots die
balkbuigtoets die spanning en vervorming wat ʼn plaveisellaag ondervind tot ʼn aanvaarbaar
hoë mate na. Die toets beskik nie oor ʼn standaard-toetsprosedure nie. Dit lei tot afwykings
terwyl dieselfde materiaal evalueer word. Om hierdie rede is die ontwikkeling van ʼn
standaard-laboratoriumprosedure nodig.
Krimpkraking is een van die grootste oorsake van plaveiselswigting. Die onwikkeling van wye
krake lei tot werksverwante skade. Krake veroorsaak areas vir die infiltrasie van water in die
onderliggende plaveisellae wat verdere agteruitgang van die plaveiselstruktuur veroorsaak.
Desnieteenstaande word ʼn evaluering van kraking op laboratoriumvlak selde gedoen. Dit
spruit uit die feit dat ʼn aantal ontwerp-riglyne kraking as ʼn natuurlike materiaaleienskap
beskou. Die padbounywerheid moet dikwels staatmaak, op onder andere, ʼn lae
sementinhoud om krimpkraking te minimeer. Hierdie tipe benadering gaan dikwels mank
aan betroubare inligting oor die materiaal se krimpingspotensiaal. Om hierdie rede is die
ondersoek van krimping op laboratoriumvlak nodig as deel van die ondersoek van die
materiaaleienskappe om die kwaliteit van materiale te bepaal.
Minimeringstegnieke verander deurlopend. Die toepassing van nanotegnologieprodukte,
soos Nanotterra Soil®, ‘n polimeersement bymiddel, wat na bewering krimpkraking in
sementgestabiliseerde lae kan minimeer, kom voortdurend op die mark. Nogtans bly hulle
geskiktheid ongespesifiseerd en afhanklik van die leweransiers. Indien ʼn krimptoetsmetode
ontwikkel word, sal die effektiwiteit van krimpverminderingsmiddels getoets kan word.
Hierdie navorsing stel die ontwikkeling van ʼn toetsprosedure vir ʼn balkbuigtoets voor met ʼn
spanlengte tot diepteverhouding van minstens nege as betroubare maatstaf van ʼn materiaal
se buigsterkte en modulus van elastisiteit. Die ontwikkelde krimptoetsmetode lewer ʼn goeie
herhaalbaarheid en is gebruikersvriendelik. Die toets verskaf ʼn goeie aanduiding van
krimpingskriteria van ferrikreet en horingfels met en sonder polimeer. Die effektiwiteit van
die polimeer hang af van die sementinhoud in die mengsel asook die tipe en kwaliteit van
die materiaal. Die navorsing verskaf insig aangaande die karakterisering van krimping,
gedragseienskappe en duursaamheid van sementgestabiliseerde materiale. Die navorsing
help mee om sementgestabiliseerde materiale beter te verstaan.
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RESILIENT MODULUS OF RECYCLED AGGREGATES AS ROAD PAVEMENT MATERIALSSingh, Pralendra 01 May 2015 (has links)
The sources of natural or virgin coarse aggregates are diminishing in alarming rate and its production is quite expensive, uses a lot of energy, and is not environmental friendly. Hence, utilizing the recycled aggregates like reclaimed or recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP) on road pavement will not only preserve the natural aggregates but also reduce the negative environmental impact. It also helps to conserve the waste landfill sites. The major downside for the use of the recycled aggregate is the quality control during its production. This research characterizes RCA samples obtained from a demolished old foundation and RAP samples from old parking lot and determines their suitability as road pavement materials. Virgin aggregates, recycled aggregates, and several blended mixtures with 20 to 80% replacement of natural coarse aggregate or virgin aggregate (NCA or VA) by weight with RCA and RAP were prepared and tested for resilient modulus (Mr) and California Bearing Ratio (CBR) test. The durability of the virgin aggregate and recycled aggregate were also determined by micro-deval test. The resilient modulus value of 100% RCA and 100% VA was found to be very similar or higher but for 100% RAP the resilient modulus is higher than that of the 100%VA. The Resilient modulus of the RAP blended mixtures increases with the increase in the content of RAP percentage and for the RCA it was not consistent. The CBR values for the blended mixtures decreases with the increase in the percentage of the recycled aggregates. The micro-deval degradation test result for RCA was more than of VA due to presence adhere materials in RCA.
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Laboratory characterisation of cementitiously stabilised pavement materialsWhite, Gregory William, Aerospace, Civil & Mechanical Engineering, Australian Defence Force Academy, UNSW January 2007 (has links)
Insitu cementitious stabilisation is an economical, environmentally sustainable and socially advantageous means of rehabilitating pavements. With the recent availability of a wide range of binders and advanced construction equipment, the characterisation of cementitiously stabilised pavement materials has become the focus of further advancement of this technology. Australian practice has moved towards the use of Indirect Diametric Tensile (IDT) methods for the characterisation of these materials. A draft protocol for the IDT test has been prepared and specifies samples to be compacted by gyratory compactor. This procedure provides for both monotonic and repeated load testing, which aims to measure the material???s strength, modulus and fatigue life. A range of host materials, including a new crushed rock and a reclaimed existing pavement base course, were assessed when stabilised with a General Purpose cement binder as well as with a slag-lime blended binder. Materials were assess for their inherent material properties, Unconfined Compression Strength (UCS), Unconfined Compression modulus, IDT strength and modulus under both monotonic and repeated load. A number of amendments and refinements to the testing protocol were recommended. These included the use of minimum binder contents to ensure the binder was uniformly distributed and to promote heavy binding of the materials to ensure they behaved elastically. It was also recommended that samples be gyratory compacted to a pre-determined sample height to allow a constant density to be achieved. The variability of the test results was examined. UCS results were found to be comparatively as variable as other researchers had reported. IDT strength results contained a similar level of variability, which was considered to be acceptable. Modulus results, both monotonic and repeated load, were found to be five to ten times more variable than strength results, which is a generally accepted trend for modulus testing. Under repeated loading, some challenges with the test protocol were encountered. The primary challenge was obtaining reliable and repeatable diametrical displacement data for modulus calculation. This was partially overcome by the insertion of smooth spacers to prevent the Linear Voltage Displacement Transformer (LVDTs) becoming caught on the sample sides. The achievement of reliable and repeatable IDT modulus results through improved displacement measurements should be the focus of future research efforts in this area.
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Laboratory characterisation of cementitiously stabilised pavement materialsWhite, Gregory William, Aerospace, Civil & Mechanical Engineering, Australian Defence Force Academy, UNSW January 2007 (has links)
Insitu cementitious stabilisation is an economical, environmentally sustainable and socially advantageous means of rehabilitating pavements. With the recent availability of a wide range of binders and advanced construction equipment, the characterisation of cementitiously stabilised pavement materials has become the focus of further advancement of this technology. Australian practice has moved towards the use of Indirect Diametric Tensile (IDT) methods for the characterisation of these materials. A draft protocol for the IDT test has been prepared and specifies samples to be compacted by gyratory compactor. This procedure provides for both monotonic and repeated load testing, which aims to measure the material???s strength, modulus and fatigue life. A range of host materials, including a new crushed rock and a reclaimed existing pavement base course, were assessed when stabilised with a General Purpose cement binder as well as with a slag-lime blended binder. Materials were assess for their inherent material properties, Unconfined Compression Strength (UCS), Unconfined Compression modulus, IDT strength and modulus under both monotonic and repeated load. A number of amendments and refinements to the testing protocol were recommended. These included the use of minimum binder contents to ensure the binder was uniformly distributed and to promote heavy binding of the materials to ensure they behaved elastically. It was also recommended that samples be gyratory compacted to a pre-determined sample height to allow a constant density to be achieved. The variability of the test results was examined. UCS results were found to be comparatively as variable as other researchers had reported. IDT strength results contained a similar level of variability, which was considered to be acceptable. Modulus results, both monotonic and repeated load, were found to be five to ten times more variable than strength results, which is a generally accepted trend for modulus testing. Under repeated loading, some challenges with the test protocol were encountered. The primary challenge was obtaining reliable and repeatable diametrical displacement data for modulus calculation. This was partially overcome by the insertion of smooth spacers to prevent the Linear Voltage Displacement Transformer (LVDTs) becoming caught on the sample sides. The achievement of reliable and repeatable IDT modulus results through improved displacement measurements should be the focus of future research efforts in this area.
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Evaluation of cracking potential of superpave mixtures with high reclaimed asphalt pavement contentAhmed, Ananna January 1900 (has links)
Master of Science / Civil Engineering / Mustaque A. Hossain / Approximately 89% of 11,000 miles of Kansas roads are surfaced with asphalt. Hundreds of thousands of tons of reclaimed asphalt pavement (RAP) are produced annually in the United States, including in Kansas. This bulk volume of RAP must be economically managed in order to achieve environmental friendliness. Recycling of RAP conserves natural resources and reduces landfill usage. However, many agencies have reported that increased RAP content produces drier hot-mix asphalt (HMA) mixtures than virgin mixtures that are susceptible to premature cracking.
In this research, laboratory-produced Superpave HMA mixtures containing increased percentages (20, 30, and 40%) of RAP materials from three RAP sources (Shilling Construction Co., Konza Co., and the Kansas Department of Transportation’s project, US 73) were studied for cracking performance. Mix designs were produced using Superpave design criteria for 12.5-mm nominal maximum aggregate size mixture. The static and repetitive Semicircular Bending (SCB) test, the Texas Overlay Tester test, the dynamic modulus test, and Viscoelastic Continuum Damage (VECD) tests were performed on laboratory-prepared samples. In general, cracking performance decreased with increased RAP content. The RAP from the US 73 project performed most consistently compared to other two sources of RAPs. Test results were analyzed using two-way Analysis of Variance (ANOVA), proving that mixtures containing 4.5% to 4.9% binder performed the best against cracking. The RAP source was found to have more effect on cracking propensity than RAP content. Mixtures with RAP content up to 40% performed satisfactorily. Tukey’s pairwise comparison method was used to compare results from all tests; VECD was determined to be the most appropriate test to evaluate cracking propensity of HMA mixtures.
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Laboratory characterization of Ohio-strategic highway research program test road pavement materialsMargowati, Margaretha January 2001 (has links)
No description available.
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Estudo do uso de agregado reciclado de resíduos de construção e demolição em misturas solo-agregado / Study of the use of recycled aggregate of construction and demolition waste in soil-aggregate mixturesOrioli, Monigleicia Alcalde 24 July 2018 (has links)
A construção civil gera impactos ambientais que merecem atenção especial, uma vez que é uma das áreas que mais produz resíduos dentre as atividades econômicas. Os agregados reciclados de resíduos de construção e demolição podem ser utilizados em diversas áreas, apresentando desempenhos mecânico e hidráulico adequados quando comparados aos agregados naturais. Esta pesquisa consiste em estudar a viabilidade o uso de agregado reciclado misto (ARM) e misturas solo-ARM como materiais geotécnicos em camadas de bases e sub-bases de pavimentos. Para isso, foram realizados ensaios de caracterização física e comportamento mecânico. Para comparação, foram estudados também um agregado natural (AN) e uma mistura de solo-AN. Os resultados mostraram que a energia de compactação teve efeito positivo sobre o comportamento do ARM e misturas de solo-ARM. Observou-se ainda que o ARM apresentou ganho de resistência e rigidez devido ao efeito de auto-cimentação. No que se refere à adição de solo, as misturas de solo-ARM apresentaram uma diminuição no valor de CBR em relação a misturas compostas exclusivamente por ARM, contudo houve um aumento nas demais propriedades mecânicas. Com base nos resultados obtidos, pode-se concluir que o ARM e as misturas solo-ARM apresentam características físicas e comportamento mecânico adequados para uso em camadas de base e sub-base de pavimentos urbanos. / Civil construction generates environmental impacts that deserve special attention, since it is one of the areas that produces the most waste among economic activities. The recycled aggregates of construction and demolition waste can be used in several areas, presenting adequate mechanical and hydraulic performances when compared to natural aggregates. This research consists of studying the feasibility of using recycled mixed aggregate (RMA) and soil-RMA mixtures as geotechnical materials in base and sub-base layers of pavements. For that, tests of physical characterization and mechanical behavior were carried out. For comparison, a natural aggregate (NA) and a soil-NA mixture were also studied. The results showed that the compaction energy had a positive effect on the behavior of RMA and soil-RMA mixtures. It was also observed that the RMA showed strength gain and stiffness due to the self-cementing properties. Concerning soil addition, the soil-RMA mixtures presented a decrease in the CBR value in relation to mixtures exclusively composed by RMA, but there was an increase in the other mechanical properties. Based on the results obtained, it can be concluded that the RMA and the soil-RMA mixtures present physical characteristics and mechanical behavior suitable for the use in base and sub-base layers of urban pavements.
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Estudo do uso de agregado reciclado de resíduos de construção e demolição em misturas solo-agregado / Study of the use of recycled aggregate of construction and demolition waste in soil-aggregate mixturesMonigleicia Alcalde Orioli 24 July 2018 (has links)
A construção civil gera impactos ambientais que merecem atenção especial, uma vez que é uma das áreas que mais produz resíduos dentre as atividades econômicas. Os agregados reciclados de resíduos de construção e demolição podem ser utilizados em diversas áreas, apresentando desempenhos mecânico e hidráulico adequados quando comparados aos agregados naturais. Esta pesquisa consiste em estudar a viabilidade o uso de agregado reciclado misto (ARM) e misturas solo-ARM como materiais geotécnicos em camadas de bases e sub-bases de pavimentos. Para isso, foram realizados ensaios de caracterização física e comportamento mecânico. Para comparação, foram estudados também um agregado natural (AN) e uma mistura de solo-AN. Os resultados mostraram que a energia de compactação teve efeito positivo sobre o comportamento do ARM e misturas de solo-ARM. Observou-se ainda que o ARM apresentou ganho de resistência e rigidez devido ao efeito de auto-cimentação. No que se refere à adição de solo, as misturas de solo-ARM apresentaram uma diminuição no valor de CBR em relação a misturas compostas exclusivamente por ARM, contudo houve um aumento nas demais propriedades mecânicas. Com base nos resultados obtidos, pode-se concluir que o ARM e as misturas solo-ARM apresentam características físicas e comportamento mecânico adequados para uso em camadas de base e sub-base de pavimentos urbanos. / Civil construction generates environmental impacts that deserve special attention, since it is one of the areas that produces the most waste among economic activities. The recycled aggregates of construction and demolition waste can be used in several areas, presenting adequate mechanical and hydraulic performances when compared to natural aggregates. This research consists of studying the feasibility of using recycled mixed aggregate (RMA) and soil-RMA mixtures as geotechnical materials in base and sub-base layers of pavements. For that, tests of physical characterization and mechanical behavior were carried out. For comparison, a natural aggregate (NA) and a soil-NA mixture were also studied. The results showed that the compaction energy had a positive effect on the behavior of RMA and soil-RMA mixtures. It was also observed that the RMA showed strength gain and stiffness due to the self-cementing properties. Concerning soil addition, the soil-RMA mixtures presented a decrease in the CBR value in relation to mixtures exclusively composed by RMA, but there was an increase in the other mechanical properties. Based on the results obtained, it can be concluded that the RMA and the soil-RMA mixtures present physical characteristics and mechanical behavior suitable for the use in base and sub-base layers of urban pavements.
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