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Asphalt-Portland Cement Concrete Composite (APCCC) is a hot-mix asphalt with air voids in the range of 25 to 30 percent which is later filled with resin modified cement grout. The resin modified cement grout consists of portland cement, fly ash, sand, water, and prosalvia (PL7) additive. The objective of the research was primarily to evaluate the asphalt-portland cement concrete composite under laboratory conditions. Asphalt-portland cement concrete composite specimens were prepared using the Marshall procedure. The physical and durability properties of APCCC were evaluated at one, three, seven, and 28 days of curing. The evaluated physical properties include stability, indirect tensile strength, compressive strength, and resilient modulus, while the evaluated durability properties include water sensitivity, freeze-thaw and chloride intrusion resistance. Specimens were also tested for different moist curing levels to evaluate the optimum moist curing period. Three moist curing periods were evaluated: no-moist curing, one-day moist curing, and three-day moist curing. The test results were compared with those of SM-5 hot-mix asphalt (a Virginia surface mix); results of chloride intrusion resistance were compared with those of portland cement concrete specimens exposed to similar conditions. The study concluded that asphalt-portland cement concrete composite is an effective alternative technique to be used as an overlay on bridge decks especially with preformed membranes, due to its high strength, durability, and lower air void content. / Master of Science

The aim of this thesis was to summarize and assess the possibility of using recycled glass in the manufacture of blended portland cements. Work was focused on examining the possibilities to improve pozzolanic properties of recycled glass with new milling processes. The formation of agglomerates material during the course of grinding and their subsequent effect on the hydration process of binders has been also examining. Part of the thesis was also focused on grindability of materials and determination of using separate or inters grinding.

Full-depth reclamation (FDR) in conjunction with cement stabilization is an established practice for rehabilitating deteriorating asphalt roads. Conventionally, FDR uses dry cement powder applied with a pneumatic spreader, creating undesirable fugitive cement dust. The cement dust poses a nuisance and, when inhaled, a health threat. Consequently, FDR in conjunction with conventional cement stabilization cannot generally be used in urban areas. To solve the problem of fugitive cement dust, the use of cement slurry, prepared by combining cement powder and water, has been proposed to allow cement stabilization to be utilized in urban areas. However, using cement slurry introduces several factors not associated with using dry cement that may affect road base strength, dry density (DD), and moisture content (MC). The objectives of this research were to 1) identify construction-related factors that influence the strength of road base treated with cement slurry in conjunction with FDR and quantify the effects of these factors and 2) compare the strength of road base treated with cement slurry with that of road base treated with dry cement. To achieve the research objectives, road base taken from an FDR project was subjected to extensive full-factorial laboratory testing. The 7-day unconfined compressive strength (UCS), DD, and MC were measured as dependent variables, while independent variables included cement content; slurry water batching temperature; cement slurry aging temperature; cement slurry aging time; presence of a set-retarding, water-reducing admixture; and aggregate-slurry mixing time. This research suggests that, when road base is stabilized with cement slurry in conjunction with FDR, the slurry water batching temperature; haul time; environmental temperature; and presence of a set-retarding, water-reducing admixture will not significantly affect the strength of CTB, provided that those factors fall within the limits explored in this research and are applied to a road base with similar properties. Cement content and cement-aggregate mixing time are positively correlated with the strength of CTB regardless of cement form. Additionally, using cement slurry will result in slightly lower strength values than using dry cement.

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.

In the Diploma thesis called "Research of seasonality in the animal dental cement and the use of this method in archaeology", I devote myself to one of the most reliable methods for determining the age cementochronology, or the analysis of increments of the dental cement. By using the method, it is possible to relatively accurately evaluate the age of an individual and to determine the death season, and thus we penetrate deeper not only to problems of palaeoecological conditions of archaeological situations, but also to economical-social relationships of then populations. Cementochronology also allows trace hunting and settlement strategies, i. e. when and for a what purpose the specific site was settled. The Diploma thesis summerizes previous knowledge about the method and compares it with the results obtained by the analysis of increments of the dental cement, which was applied on referential zoological and archaeozoological material.

A maior preocupação deste trabalho é com as moradias das populações de baixa renda que na maioria dos casos são precárias não atendendo aos requisitos mínimos de habitabilidade. Para encarar este problema utilizamos como instrumento o conceito de tecnologia apropriada tendo em vista que as tecnologias tradicionais e modernas não tem apresentado bons resultados neste campo. Isto não quer dizer que estamos defendendo apenas uma saída tecnológica para os problemas da habitação popular. Para exemplificar a viabilidade deste enfoque, estudamos duas aplicações, em tijolos e em paredes monolíticas de solo-cimento, onde se colocaram as questões de escolha do solo, dosagem e ensaios de avaliação tais como: resistência à compressão, durabilidade, absorção d\'água, impermeabilidade. Procuramos também, através das aplicações, disseminar a metodologia empregada, que acreditamos possa ser utilizada no desenvolvimento de outros materiais. / The principal objective of this Project is housing for low income people, wich is in the most part poorly constructed without the minimum standards of habitability. To face this problem, the appropriate technology approach were applied bering in mind that traditional and modern ones have not been suited to best resolve this type of housing. But this does not mean that this housing problem is only a technological challenge. As an example two cases were studied, one in pressed earth and the other in rammed earth, both using soil-cement. Soil selection, the cement to soil mixture, compressive strength, durability, water absorption and impermeability tests were evaluated. Besides these examples it is considered that this methodology can be applied to other studies of other materials.

A produção de cimento gera um impacto ambiental negativo, principalmente relacionado à emissão de dióxido de carbono (CO2). O clínquer do cimento sulfoaluminato de cálcio belítico (CSAB) possui um menor teor de óxido de cálcio e é produzido com uma reduzida temperatura de sinterização (aproximadamente 200ºC a menos em relação ao clínquer Portland), sendo considerado mais eco-amigável. Para a produção do cimento CSAB são necessárias matérias-primas ricas em alumínio e convencionalmente a bauxita é o minério utilizado para compor a farinha, o que mais onera a produção desse tipo de cimento. Soma-se ainda o fato que a geração de resíduos e subprodutos industriais torna-se inerente aos processos e o coprocessamento de resíduos vem sendo cada vez mais utilizado por razões ambientais e energéticas. Logo, fontes alternativas de alumina são fundamentais para a viabilização deste cimento e o aproveitamento de resíduos agregaria um valor econômico e sustentável ao produto final. De modo estequiométrico, a bauxita pode ser completamente substituída pelo lodo de anodização do alumínio (LAA), o qual também pode complementar o conteúdo de alumínio de outros resíduos, valorizando-os. O objetivo deste estudo foi avaliar a produção e as propriedades de clínqueres/cimentos CSAB a partir da substituição da bauxita por cinza pesada e LAA. Para a caracterização das matérias-primas, clínqueres e cimentos nos estados anidro e hidratado foram utilizadas as seguintes técnicas: fluorescência de raios X; microscopia eletrônica de varredura e espectrometria por energia dispersiva; termogravimentria; calorimetria; e difração de raios X com refinamento pelo método de Rietveld. A partir dos resultados obtidos, a substituição da bauxita foi limitada a nível parcial devido à elevada formação de belita e periclásio. Nos clínqueres produzidos, foi constatado que a presença da cinza pesada favorece a formação da estrutura cristalina ortorrômbica da fase ye’elimita. A presença dos resíduos altera a quantificação das fases, porém não compromete a estabilização das mesmas. A presença dos resíduos na composição dos cimentos afeta o período inicial de hidratação devido à redução do conteúdo de ye’elimita. Nos clínqueres produzidos com cinza pesada, ocorre a formação de até 12,6% da fase alita a 1250ºC, principal constituinte do clínquer Portland. / Cement production generates high negative environmental impact, mainly associated to CO2 emissions. Calcium sulfoaluminate belite cement clinker (CSAB) has lower content of calcium oxide, and sintering reduced temperature (about 200°C lower than that used for Portland clinker), being considered as eco-friendly binder. For its production high amount of alumina is required, however the scarcity and high cost of bauxite make these cements costly. Additionally, the generation of waste and by-products becomes a drawback in the industrial processes and the coprocessing of wastes in cement plants is increasing for environmental and energy savings reasons. Alternative sources of alumina would add an economic and sustainable value to the final product and previous work has shown that the aluminum anodizing sludge can replace bauxite in the production process. Other sources of wastes can also be a possibility to increase the production and reduce the raw materials costs of these cements. Thus, the objective of this study was the evaluation of novel CSAB cements produced with bauxite replacement by bottom ash and aluminum anodizing sludge. CSAB cements were produced in the laboratory from different amounts of sludge and ashes. The raw materials, clinkers/cements and hydration products were physicaly-chemicaly and mechanical characterized. Results showed that the mineralogy composition of CSAB clinker was strongly affected due to the addition of bottom ash. The amount of bottom ash waste replacing bauxite controls the belite and periclase formation. Also it influences the early age hydration due the reduced ye’elimite formation and important changes in the crystalline structures of this phase occurs in the clinkers. Clinkers prepared from these replacement, are able to form 12.6% of alite (main phase Portland clinker), not normally found in CSAB clinkers, being sintered at 1250°C.

Cement clinker production is a highly resource and energy intensive process and contributes substantially to annual global anthropogenic greenhouse gas emissions. One potential pathway to reduce the environmental footprint of cement-based materials is through the reduction of clinker content in concrete by partial replacement of cement with fillers. In this investigation, the partial replacement of cement with chemically inert nano and microsized fillers of titanium dioxide (TiO₂) and limestone was examined. The effects of nano and micro fillers on early-age properties, long-term properties, photocatalytic properties (for TiO₂-cement mixtures) and life cycle costs were measured and compared. Investigation of early-age properties shows that nanoparticles increase rate and degree of early cement hydration and chemical shrinkage due to heterogeneous nucleation effect. In contrast, coarser microparticles (>3µm in this research) maintain or marginally decrease the rate and degree of early cement hydration and decrease chemical shrinkage due to a dilution effect. In addition, temperature sensitivity of hydration reactions increases in the presence of nanoparticles. Investigation of long-term properties shows that pore size refinement is possible with the partial replacement of cement with nanoparticle fillers. But the long-term tests of filler-cement mixes also demonstrate that, compared to ordinary portland cement mix, the strength decreases and permeability increases. Analysis of photocatalytic properties of TiO₂-cement mixtures showed a lack of an appropriate testing procedure for nitrogen oxide (NOₓ) gas conversion by cement-based materials. Thus, a new standardized procedure and photocatalytic efficiency factor for characterizing photocatalytic NOₓ binding by cementitious materials is proposed. Life cycle analysis demonstrates that although inclusion of TiO₂ increases initial environmental impact of cementitious materials, the innovative photocatalytic properties of TiO₂ could improve sustainability. Life cycle analysis also shows that partial replacement of cement with limestone decreases environmental impact of cementitious mixtures due to lower processing “costs” of limestone compared to cement. Thus, the results from the current research demonstrate that variation of dosage and particle size of inert fillers can be used to tailor properties and structure of cement-based materials and that environmental sustainability can be improved by partial replacement of cement with inert fillers that introduce additional functionalities or fillers with lower embodied-energy and emissions.

Multiwall carbon nanotubes (MWNTs) have extraordinary mechanical and thermal transport properties. They significantly improve the static and dynamic mechanical properties of acrylic orthopaedic bone cement when added to the dry cement polymer powder. Understanding the role MWNTs play on bone cement polymerization temperatures will lead to improved mechanical integrity of the cement-bone interface in joint arthroplasties. It was determined through thermal testing that MWNTs increased the polymerization time of the methylmethacrylate by 45-460% and decreased the peak exothermic temperature of bone cement with and without antibiotics. The flow of heat produced during polymerizing cement was reduced 25-85% with the addition of MWNTs to the cement powder. This decreases the probability of thermal necrosis and “hot” spots caused by high exothermic polymerization temperatures that can destroy the bone adjacent to the cement. These high temperatures also affect the potency and range of antibiotics used in arthroplasty. Isothermal and elution studies determined that MWNTs altered the heat flow and amount of antibiotic release from bone cement during polymerization. Antibiotic elution from bone cement containing MWNTs could match the elution seen in pure cement. The alteration of the flow of heat from bone cement leads to new options for heat-labile antibiotics in total joint arthroplasty.