New Sustainable with no CO2 emission cold mix asphalt (CMA) for road and highways surfacing is successfully developed from wastewater sludge ash normally sent to landfills. The Paper reports; ...durability in terms of water sensitivity, aging and contamination levels of heavy metals of the new developed novel CMA containing upgraded fly and bottom ash secondary cementitious materials from United Utilities fly and bottom ashes. Road engineers currently restricted the use of conventional CMA containing conventional limestone fillers (LF) for use in walkways and light trafficked roads only, as these mixtures needs from 2 to 24 months for curing. Conventional CMA mixtures also have high voidage contents and thus low traffic bearing capacity. The durability of these mixes is low especially in the UK and European countries where the climate is predominantly wet and cold.In Germany and France, ordinary Portland cement (OPC) replaced the filler used in traditional CMA. Although this allows the new CMA to be used in roads for light and heavy trafficked loads. The materials are not environmentally friendly, as one tone of cement releases approximately one tone of CO2 emission during their manufacturing process.
The results of the new developed CMA are satisfying the British and European codes of practices requirements. The new novel mixtures are also; highly cost-effective compared with the use of Hot Mix Asphalt (HMA), has no CO2 emission during mixing construction, and has no health and safety issues compared with the HMA manufacturing and application process.
Crystal morphology is a significant property in manufactured materials. Related to crystal structure and influenced by environment, manipulating crystal morphology is important for tailoring of ...product properties to performance and quality control standards. There is a shortage of high-quality morphological data for organic crystals. A largely untapped wealth of such data for over 2000 organic crystals is available in P. von Groth’s Chemische Kristallographie, a multivolume reference work, published in the early 20th century. The data are available online, but comparisons with more recent morphological and structural data are not straightforward. Here, the opportunity for a standardized, systematic approach linking Groth’s morphology data to crystal structures in the Cambridge Structural Database (CSD) is presented. A method is proposed based on matching unit cells to store morphological data in a standard formatthe “morphology.cif”. This method is illustrated with four examples: benzophenone, glycine, urea, and α-lactose monohydrate, highlighting the particular challenges associated with polar morphologies. The steps necessary to implement such an approach systematically and hence to make maximum use of Groth’s work are discussed.
The anhydrous forms of theophylline and the stability relationships with the monohydrate, Form M, are characterized. Form II, kinetically stable at room temperature and considered as the most stable ...form during the 70-year history of theophylline usage, is observed to act as an intermediary for conversions between other forms. Form IV, the thermodynamically stable form at room temperature, is shown to be enantiotropically related to Form II and undergoes a solid state transition on heating. The enantiotropic relationship between Forms II and I was investigated, and it was established that a Form II to I transition is observed only in samples generated using specific methods. Form III was found to be a high energy solid form which can only be generated by dehydration of the hydrate. Upon heating, Form III shows an exothermic transition to Form II. Upon rehydration, Form III is extremely hygroscopic and converts initially to Form II and then to Form M. The complexity of anhydrate–hydrate relationships is illustrated, and the influence of sample history on batch purity is shown, which in turn may influence solid form transformations.
Context: Mini-tablets are compact dosage forms, typically 2-3 mm in diameter, which have potential advantages for paediatric drug delivery. Extended release (ER) oral dosage forms are intended to ...release drugs continuously at rates that are sufficiently controlled to provide periods of prolonged therapeutic action following each administration, and polymers such as hypromelllose (HPMC) are commonly used to produce ER hydrophilic matrices.
Objective: To develop ER mini-tablets of different sizes for paediatric delivery and to study the effects of HPMC concentration, tablet diameter and drug solubility on release rate.
Methods: The solubility of Hydrocortisone and theophylline was determined. Mini-tablets (2 and 3 mm) and tablets (4 and 7 mm) comprising theophylline or hydrocortisone and HPMC (METHOCEL™ K15M) at different concentrations (30, 40, 50 and 60%w/w) were formulated. The effect of tablet size, HPMC concentration and drug solubility on release rate and tensile strength was studied.
Results and Discussion: Increasing the HPMC content and tablet diameter resulted in a significant decrease in drug release rate from ER mini-tablets. In addition, tablets and mini-tablets containing theophylline produced faster drug dissolution than those containing hydrocortisone, illustrating the influence of drug solubility on release from ER matrices. The results indicate that different drug release profiles and doses can be obtained by varying the polymer content and mini-tablet diameter, thus allowing dose flexibility to suit paediatric requirements.
Conclusion: This work has demonstrated the feasibility of producing ER mini-tablets to sustain drug release rate, thus allowing dose flexibility for paediatric patients. Drug release rate may be tailored by altering the mini-tablet size or the level of HPMC, without compromising tablet strength.
Little is known concerning the pathway of the crystallization of the thermodynamically stable polymorph of theophylline, form IV. Here we study the reasons why the thermodynamically stable ...theophylline form IV can be obtained only by slow, solvent mediated phase transformation (SMPT) in specific solvents, and whether the presence of prenucleation aggregates affect the polymorphic outcome. Solution concentration, polymorphic composition and morphology were monitored over time during the transformation from form II to form IV in several solvents. NMR and FTIR spectroscopy were used to detect prenucleation molecular aggregates present in the solutions. It was determined that theophylline self-associates in solvents which are good H-bond donors and the presence of these aggregates hinder the nucleation and phase transformation. SMPT from form II to form IV is a nucleation-growth controlled polymorphic transformation, nucleation is most likely homogenous, and form IV crystals grow along the (001) plane, forming plate-like crystals.
•An eco-friendly cold asphalt concrete for binder course mixtures has been developed.•A novel alkali activated binary blended cement filler system has been uncovered.•Mechanical and durability ...properties, and microstructure have been evaluated.•Alkali activators have improved the levels of pozzolanic reactivity in the BBCF.•A substantial improvement in mechanical properties for the novel ABBCF is demonstrated.
A slow rate of curing and the long time necessary to achieve full strength has led cold asphalt mixes (CAM) to be considered poorer in comparison to hot mix asphalt over the last decades. This piece of research aimed to develop a new fast-curing and environmentally friendly cold asphalt concrete for binder courses mixture (CACB). It has the same gradation as that of traditional hot asphalt concrete mixtures but incorporates a binary blended cementitious filler (BBCF) containing waste, high calcium fly ash (HCFA) and fluid catalytic cracking catalyst residue (FC3R) activated by a waste alkaline NaOH solution. The research concludes that incorporating an alkali activated binary blended cementitious filler (ABBCF) with CACB significantly improves the mechanical properties and water susceptibility. In addition, the high performance ABBCF mixture has a substantial lower thermal sensitivity than traditional hot asphalt concrete binder course mixtures. SEM analysis revealed that the main crystallisation had taken place at an early stage of the new ABBCF. More significantly, the new CACB mixture has a comparable stiffness modulus with the traditional asphalt concrete binder course after a very short curing time (less than one day).
The aim of this research was to develop a sustainable and ecologically sound, non-traditional cold mix asphalt (CMA) that can be used in the construction industry. This new type of CMA incorporates ...wastewater sludge fly ash (UFA) and bottom ash (UBA) as a replacement filler for ordinary Portland cement and limestone. Silica fume (SF) was also used as an additional filler. The mechanical and durability characteristics of the new CMAs were examined in terms of indirect tensile stiffness modulus (ITSM), and rutting, fatigue, water and fuel resistance. The results showed that CMA with 2.1% OPC +3.9% UFA at 3 days of age, had ITSM values 11 times that of traditional CMA, while CMA with 2.1% OPC+ 3.3% UFA +0.6% UBA, had ITSM values 5 times that of traditional CMA at 28 days of age. SF activated hydration for both mixes, significantly increasing ITSM. These results indicate that CMA has a comparable mechanical performance to standard Hot Mix Asphalt (HMA) mixtures for use as surface pavement layers. This study offers a novel CMA with improved mechanical performance. It is economically effective and ecologically beneficial, compared to HMA, due to its ability to accommodate wastewater sludge ashes that are often disposed of in landfill sites.
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•Wastewater sludge fly and bottom ash were used in novel CMA mixtures.•A new technology for producing a low carbon CMA, was developed.•High values for indirect tensile stiffness modulus were achieved.•Rutting resistance was investigated using wastewater sludge ash.•There was an improvement in the durability characteristics of CMA containing wastewater sludge ash.
The little stiffness modulus, high voidage and long curing time has limited the use of CBEM＇s （cold bituminous emulsion mixtures） in road and highways to pavement experiencing low traffic. The aim of ...this study is to improve the properties of gap graded CRA （cold rolled asphal0 containing OPC （ordinary portland cement） as filler by addition of a by-product material as an activator. OPC was added to the CRA as a replacement to the conventional mineral filler （0%-100%）, while LJMUA （Liverpool John Moores University Activator） was added as an additive in the range from 0%-3% by total mass of aggregate. Laboratory tests included stiffness modulus and uniaxial creep test to assess the mechanical properties. The results have shown a considerable improvement in the mechanical properties from the addition of LJMUA to the CRA containing OPC especially for the early life stiffness modulus that is the main disadvantage of the cold mixtures.
•Pozzolanic reaction within the novel non-portland binder was compared with OPC.•Conversion of AFt to AFm in the binder was confirmed by TG/DTA and FT-IR analysis.•Reduced density of C-H phase within ...the novel binder after long term curing revealed.
The development and production of new materials requires advanced analytical characterisation to explain the relation between the physico-chemical structure of the material and its properties. Highly integrated microelectronic structure analysis of surfaces with laser beams and X-ray fluorescence aided devices are found to be helpful for providing important information, including the interrelationships between physical, chemical, mechanical and durability characteristics of the new developed products. In most instances no single technique provides all the needed information and hence simultaneous application of several techniques becomes necessary. This study was aimed for hydration analysis, characterization and evaluation of a new novel non-Portland binder (NPB) with waste paper sludge ash (PSA) using FTIR and TG/DTA. The progressive formation of hydration products within the non-Portland binder was identified and their microstructural characteristics were analysed. The stable and non-expansive nature of secondary ettringite formation was also identified after a period of 365 days curing.
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