Sole Binder Research Articles

THE HIGH VOLUME REUSE OF HYBRID BIOMASS ASH AS A PRIMARY BINDER IN CEMENTLESS MORTAR BLOCK

High Calcium Wood Ash (HCWA) and Pulverised Fuel Ash (PFA) are by-products from the wood biomass and coal energy production which are produced in la rge quantity with combined annual production of 500 million tonnes. This poses a serious problem for di sposal of the waste material especially at places w here land is scarce. The prescribed study was aimed to examine the mineralogical phases and their respective amount present in the industrial wastes which gover ns the hydration mechanism towards self-sustained solidification of the ashes when used in combinatio n. Besides, the influence of various forming pressu re and hydrothermal treatment temperature on mechanical strength performance of HCWA-PFA cementless mortar blocks was also examined. In the study, the mechani cal strength of the HCWA-PFA cementless mortar block produced using various forming pressure and h ydrothermal treatment temperature was assessed in terms of compressive strength and dynamic modulus. The results of the study are indicative that HCWA i s rich in calcium oxide and potassium oxide content. This enables the hybridization of HCWA with the amorphous silica and alumina rich PFA to form a sol id geopolymer binder matrix for fabrication of cementless mortar block. Throughout the study, dime nsionally and mechanically stable HCWA-PFA geopolymer mortar blocks were successfully produced by press forming and hydrothermal treatment method. Based on statistical analysis, the hydrothe rmal treatment temperature has a statistically insignificant effect on the mechanical strength of the HCWA-PFA cementless mortar blocks. The dominant factor which governs the mechanical strength of the HCWA-PFA cementless mortar blocks was found to be the hydraulic forming pressure. Moreover, it was fo und that hybridized HCWA-PFA can be recycled as the sole binder for fabrication of cementless concrete block which is a useful construction material.

ChemInform Abstract: A Review of Binders Used in Cemented Paste Tailings for Underground and Surface Disposal Practices

AbstractReview: 123 refs.

Polyurethane coatings prepared from CNSL based polyols: Synthesis, characterization and properties

Abstract Conventional polyurethane chemistry based on polyol and isocyanate chemistry is widely used for many applications ranging from plastics to coatings, constructions, pharmaceuticals, foods, etc. The growing concern over depletion of petrochemical materials and their rising prices has led to search for environment friendly renewable materials. Cardanol derived from cashew nut shell liquid is one such renewable material which has reactive phenolic group and aliphatic double bond that could be tailor-made to produce novel functional materials for polymer and coating applications. This has previously been used for preparation of phenolics, epoxy resins and phenalkamine hardners. Diglycidyl ether of cardanol which is commercially available, is used as epoxy resin or modifier in epoxy formulations. In the present work, this was modified by simple one step ring opening reaction to produce polyols with different number of functionalities. The various polyols prepared were cured with polyisocyanate cross-linkers and applied on metallic substrates. The cured coatings were evaluated for physical, mechanical, chemical and thermal properties. The study conducted showed that the prepared polyols could be used as sole binder for coating formulation with overall excellent properties.

Effect of binder content on the performance of alkali-activated slag concretes

This paper assesses the mechanical and durability performance of concretes produced using alkali silicate-activated ground granulated blast furnace slag as sole binder. Alkali-activated concretes are formulated with 300, 400 and 500 kg slag per m 3 of fresh concrete, and their performance is compared with reference concretes produced using Portland cement (OPCC). Regardless of the binder content, the alkali-activated slag concretes (AASC) develop higher compressive strength than the comparable reference concretes. A higher binder content leads to increased strength in both AASC and OPCC at 28 days. However, at 90 days, the performance penalty for low binder content is more significant in the OPCC than AASC samples. Permeability, water sorption and carbonation resistance properties are also improved at higher binder contents. By controlling mix design parameters, it is possible to produce AASC with mechanical strength and durability comparable to conventional Portland cement concretes.

Structure and strength of NaOH activated concretes containing fly ash or GGBFS as the sole binder

The influence of the concentration of the activating agent (4, 6, or 8 M sodium hydroxide solution), and activator-to-binder ratio (0.40, 0.50, or 0.60) on the compressive strengths, pore structure features, and microstructure of concretes containing Class F fly ash or ground granulated blast furnace slag (GGBFS) as the sole binder is reported. The starting material contents and the curing parameters (temperature and curing duration) are optimized to provide the highest compressive strengths. Statistical analysis of the compressive strength results show that the activator concentration has a larger influence on the compressive strengths of activated concretes made using fly ash and the activator-to-binder ratio influences the compressive strengths of activated GGBFS concretes to a greater degree. Activated fly ash concretes and pastes are found to be more porous and contains a larger fraction of pores greater than 10 μm in size as compared to activated GGBFS mixtures. The differences in the microstructure and the reaction products between activated fly ash and GGBFS pastes are detailed.

Effect of silicate modulus and metakaolin incorporation on the carbonation of alkali silicate-activated slags

Accelerated carbonation is induced in pastes and mortars produced from alkali silicate-activated granulated blast furnace slag (GBFS)–metakaolin (MK) blends, by exposure to CO 2-rich gas atmospheres. Uncarbonated specimens show compressive strengths of up to 63 MPa after 28 days of curing when GBFS is used as the sole binder, and this decreases by 40–50% upon complete carbonation. The final strength of carbonated samples is largely independent of the extent of metakaolin incorporation up to 20%. Increasing the metakaolin content of the binder leads to a reduction in mechanical strength, more rapid carbonation, and an increase in capillary sorptivity. A higher susceptibility to carbonation is identified when activation is carried out with a lower solution modulus (SiO 2/Na 2O ratio) in metakaolin-free samples, but this trend is reversed when metakaolin is added due to the formation of secondary aluminosilicate phases. High-energy synchrotron X-ray diffractometry of uncarbonated paste samples shows that the main reaction products in alkali-activated GBFS/MK blends are C–S–H gels, and aluminosilicates with a zeolitic (gismondine) structure. The main crystalline carbonation products are calcite in all samples and trona only in samples containing no metakaolin, with carbonation taking place in the C–S–H gels of all samples, and involving the free Na + present in the pore solution of the metakaolin-free samples. Samples containing metakaolin do not appear to have the same availability of Na + for carbonation, indicating that this is more effectively bound in the presence of a secondary aluminosilicate gel phase. It is clear that claims of exceptional carbonation resistance in alkali-activated binders are not universally true, but by developing a fuller mechanistic understanding of this process, it will certainly be possible to improve performance in this area.

Impact of the intumescent formulation of styrene acrylic-based coatings on the fire performance of thin painted red lauan (Parashorea spp.) plywood

Intumescent material with commercial resin, such as styrene acrylic copolymer resin, has been demonstrated to be extremely effective in improving the fire performance of wooden materials used for indoor furnishing. The formulation of the coating is a key to its ability to improve flame retardance. This study investigates the enhancement for painted thin red lauan (Parashorea spp.) plywood. The ability of the material to retard flame arises due to the interactions between the four major components of intumescent formulation: (1) a binder resin (BR), styrene acrylic emulsion resin, (2) a carbonizing substance (CS), pentaerythritol (3) a foam producing substance (FPS), melamine and (4) a dehydrating agent (DA), ammonium polyphosphate. This paper compares the fire performance of the plywood when coated with resin of differing BR/CS ratios (designated as the FRS series) and FPS/DA ratios (designated as the FRD series), by means of a cone calorimeter. These intumescent formulations significantly enhanced the fire retardancy of painted plywood, exhibiting lower peak heat release rates, higher expansion of the intumescent layer and longer time to peak heat release rates (PHRR), when compared to plywood panels coated with sole binder resin. However, worse performance was presented when compared with the data for uncoated plywood panels if the intumescent was produced by equal ratio of the four components. Therefore, the formulation of the intumescent is important. Additionally, lower BR contents in the FRS series and lower FPS contents in the FRD series further enhanced flame retardancy. Advanced investigation by IR and 31P NMR demonstrated that lower BR and FPS content extends the survival duration of the phosphor-carbonaceous structure of chars. The findings in this study enhance the state-of-the-art understanding of the effect of the intumescent.

Strength and elasto-plastic properties of non-industrial building materials manufactured with clay as a natural binder

The objective of this article is to study the mechanical performances of non-industrial materials made with soils containing argillaceous minerals as the sole binder (materials referred to as earthen). The renewed interest in earthen construction requires, in the current context, a scientific approach to these materials and a re-examination of certain techniques such as that of adobes. These adobes are obtained starting with very argillaceous soil saturated with water and poured into wooden moulds. Thus with a soil containing 25% clay, two types of adobe were studied: traditional adobe and Pressed Adobe Blocks (PABs). They were made with a variation in moulding water. Once dried, they were subjected to an unconfined compression test with three loaded and unloaded cycles at 30% of the compressive strength. This test, which takes into account the specificity of adobes, made it possible to determine their compressive strength, initial tangent modulus ( E t) and equivalent modulus during cycles ( E eq). From the results obtained, it appears that the mechanical performances of adobes depend on the moulding water content ( W m) and the manufacturing process used. The PABs with a lower W m have a higher compressive strength than the adobes. Moreover, they are more homogeneous, although both types of adobe have an elastoplastic behavior. Therefore, for laboratory testing the use of PABs is recommended rather than the use of adobe.

Durability of concrete incorporating GGBS activated by water-glass

The environmental concerns related to the production of cement in terms of the energy consumption and the emission of CO 2 lead to the search for more environmentally viable alternatives to cement. One of those alternative materials is ground granulated blast-furnace slag is used not only as a partial replacement to cement but also as the sole binder in the form of alkali-activated slag (AAS) to produce concrete. In addition to a control OPC mix, an OPC/slag mix with 60% cement replacement by GGBS, and also AAS mixes were prepared with slag as the sole binder, activated with water glass at two dosages, 4% and 6% Na 2O (by weight of slag). Two types of water glass were used, one in a solution form and the other in a solid granules form. The two forms of the activator used were also of different silicate modulus ( M s); 1.65 for the solution form and 1.0 for the granule form. All the mixes had the same binder content and w/b = 0.48. This paper presents the results of the durability related tests that were carried out which included, chloride penetration resistance, porosity, carbonation, and alkali–silica reaction. The effect of the different parameters including the activator type and dosage are discussed. The results give indications on the good durability of alkali-activated slag concrete compared to conventional OPC concrete.

Investigation of Portland Cement Concrete Mix Consistency and Concrete Performance Using a Two-Stage Mixing Process

The objective of this study was to investigate the effects of different mixing processes, particularly a two-stage mixing process, on fresh and hardened characteristics of pastes and concrete. Characteristics studied for pastes included rheological effects (i.e., yield stress, thixotropy, viscosity, and peak stress) and compressive strength for mixes prepared in a Hobart mixer and a high-shear mixer. Parameters measured for the concrete study included fresh concrete air and slump, compressive strength, and hardened concrete air void characteristics. The paste study results show that for increased mixing time, the compressive strength is not significantly influenced. The rheology results show that longer mixing times with a high-shear mixer lead to lower viscosity, thixotropy, and peak stress; this indicates better-mixed slurry when compared with a shorter mixing time and the Hobart mixer. The fresh concrete made with the two-stage mixing process shows reduction in air content, and the hardened concrete shows little change in compressive strength when compared with the concrete produced with the one-step mixing process. Rapid air void analysis results indicate that the two-stage mixing method may be beneficial for mixes containing portland cement as a sole binder in freeze–thaw durability.

Hydration of combustion ashes — a chemical and physical study

This study deals with curing of mortars in which coal ashes from both PC and FBC boilers were the sole binder components. The work focuses on the hydration products and the hydration results are correlated with the physical properties of the cured beams from 10 formulations of mortar made of sand and ash blends. Curing was extended to two to three years and the beam specimens were cured in water for swelling measurements and in moist atmosphere for shrinking measurements. Mechanical strength and dimensional stability were tested periodically and porosity measurements were also made. Separation by density of pulverized mortar samples was performed to obtain the light fractions containing the hydrates formed. The cured mortars and these separated fractions were analysed and the hydrates identified included AFt, gypsum, portlandite, a variety of hydrated calcium aluminosilicates and amorphous C–S–H. The composition of C–S–H, as characterized by atomic ratios of various elements referred to Ca indicated considerable replacement of Si by Al and S. The degree of hydration, as indicated by the percentage of light fraction in the mortar or by other properties, and the chemical characteristics of the ash blends were related to the mechanical properties of the cured mortar using two novel indices. One of these relates the silicoaluminous to sulphocalcic components and the other the available free lime to sulphate content of the mortar.

Utilization of Polyurethane Foam Scrap as a Sole Binder for Recycling of Automotive Interior Trim Products

A number of rear-seat-to-back-window trim panels (CHMSL covers) were manufactured by thermoforming ground polyurethane-cored headliner (UROCOR) scrap with PMDI as a binder with and without water as a component of the composite mixture utilizing industrial equipment at a Lear plant in Holland, Michigan. Unexpectedly, it was found that UROCOR scrap which contains a significant amount of flexible and semi-rigid polyurethane foam can be thermoformed without addition of PMDI. In order to confirm that the polyurethane scrap can be used as a binder, the polyurethane seating foam scrap was successfully recycled as the sole scrap and in 75/25 and 50/50 mixtures with resinated fibers.

Marine anti‐corrosion paints based on thiouracil compounds

The inhibition of marine corrosion of steel by 6‐amino‐2‐thiouracil (I) and its derivatives 6‐benzylideneamino‐2‐thiouracil (II) and 6‐p‐chlorobenzylideneamino‐2‐thiouracil (III) has been tested on laboratory scale using electrochemical technique which was performed on mild steel in sea water medium and on field scale through the incorporation of the compounds individually in marine paints compositions. The paints containing the compounds were applied on unprimed steel and the coated panels were tested in Alexandria Eastern Harbour water (Egypt). The electrochemical measurements indicated that both compounds (I) and (III) acted as cathodic‐type inhibitors, but the data of compound (II) showed neither cathodic nor anodic inhibition. Two marine paint compositions were prepared using different binder materials. The three compounds were added individually in both paint compositions. The paint composition based on the soluble resin material as a sole binder and containing compound (I) showed the best corrosion protection of its steel surface till more than two months followed by the paint composition containing compound (III). The same paint containing the compounds showed antifouling property for four months.

Pavements on the base of polymer-modified drainage concrete

Drainage concrete on the base of cement as the sole binder is a long standing subject in research since more than 30 years. The material is already used in the application area of filter tubes, sound proofing walls, cycle tracks, footpaths and traffic surfaces like parking lots. Up to now this material could not be used for roads, motorways or racing tracks because of the missing mechanical stability of these pavements. The use of a second binder, a polymer emulsion, in addition to cement can improve the mechanical stability, the resistance to deformation, that means: no rutting. The polymer emulsion should exhibit a very good cement compatibility, a glass transition temperature above RT and in the fresh mortar–concrete it should induce a higher flexural tensile strength. The emulsion used in the experiments to optimise a recipe for practical uses is on the monomer-base of styrene–acrylics (Mowilith LDM6880). The drainage concrete can be worked out in strength classes ( B≤25 N mm −2) in mixtures with water:cement ratios of about 0.24:0.26, which contain double-broken and screened chippings, cement and emulsion only. Those pavements exhibit high noise reduction, high sound absorbency in the range of 5–7 dB(A), high drainage effect, e.g. no sheets of spray from wheels, no aquaplaning, reduced black ice formation in winter and a good long term stability. The void content is adjustable between 15 and 25%.

Sulphur concrete in products for agriculture

Sulphur concrete (SC) is a material in which modified sulphur is used as the sole binder. It holds a lot of potential for application in products, designed for chemically difficult environments, such as frequently occur in agriculture. Two recent studies by Hellers and Thylen and by Ekblad prove the feasibility of the material. In the first, the fast-binding material was unreinforced and subjected to a combined attack from organic acids and high-pressure washing. In the second study, the material was prestressed and tested for mechanical capacity in bending and shear. Also, the bonding capacity of the prestressing strand to the surrounding material was tested with satisfactory results. Prestressed slats have now been tested over six months for creep and in practice under fattening pigs, including observations of deterioration, without regard to the possible chemical mechanisms involved. The creep seems to occur mainly within the first month. Indications of corrosion in practical tests confirm the visual impression that the material is not perfect, showing flaws and longitudinal cracks due to insufficient compaction in the casting process. In order to improve that process it has recently been concluded that the true thermoplastic nature of SC must be accounted for in the solidification phase. By computer modelling it is now possible to analyse the progress of the solidification front and the possibility of keeping paths open for a compensating binder flow which can fill out the contraction volume of the binder in the transition from the liquid to the solid stage. Probably, vibration energy must also be added to the process in order to obtain a fully compacted and uncracked product. The further practical implementation of a refined casting process remains to be realized within the next year, 1992–93.

Does the Brand of Calcium Carbonate Product Used Affect Serum Phosphorus Levels in Hemodialysis Patients: A Pilot Study

This pilot study was conducted to evaluate the therapeutic effectiveness of different over-thecounter brands of calcium carbonate used by hemodialysis patients in two centers. Selection criteria included (1) calcium carbonate being the sole phosphate binder, and (2) patients who were fairly compliant with treatments, diet, and medications. Patients were instructed on a phosphorus diet of ≥1,000 mg, and had a serum phosphorus of ≤2.10 mmol/L (6.5 mg/dL) in January 1991. Data were collected over the same 5-month period on 28 patients. Eleven products were used by the patient sample. The home test for calcium dissolution evaluation was used. The mean per tablet time for dissolving was 18.46 minutes (range, 7 to 60 minutes). The mean phosphorus level drawn monthly was 1.63 mmol/L (5.05 mg/dL) ± .39 mmol/L (1.21 mg/dL). There was a negative correlation of r = -.16 between the dissolution rate and phosphorus levels. The initial hypothesis was that more rapidly dissolving calcium carbonate products would be more therapeutically effective for phosphate binding control. This pilot study concludes that slower dissolving products may be more effective in controlling serum phosphorus levels.

Quebracho based polyphenols for use in wood panel adhesive system

Colatan polyphenols are available in sufficient quantity. They meet the expected future needs of glue and binder producers for a raw material enabling them to satisfy the requirements for a low fuming moisture resistant chipboard and medium density fibreboards (MDF) binders. The development of such glue systems using Colatan as a sole binder or as a binder additive by the phenolic and amino resin producers has already begun, and promises a bright future for Colatan.