Gypsum Composition with a Complex Based on Industrial Waste

Producing present-day constructional materials on mineral binders is directly connected to the use of micro- and ultra-disperse technogenic modifying agents. They allow to obtain the maximum particle-particle packing in composition, provide rational raw mix design, contribute to structure formation process. The present article is devoted to the investigation of searching the most rational solution for the problem of basalt waste utilization, with the basalt waste being the valuable secondary raw material resource. The studies have shown that it is possible to use basalt dust as admix to gypsum composites. The basalt waste, by changing the composition grain-size distribution, provides the better particle-particle packing both for finegrained and coarse waste fractions, thus having positive effect on modified gypsum rock structure. Optimization of internal structure also contributes to the increase of gypsum rock strength properties. The obtained gypsum composite can be profitably employed for manufacturing small-piece walling gypsum materials by casting process.

The alternative composites’ production alleviates the serious problem generated by global warming. Methods to reduce the amount of cement used in concrete production, for example, are being investigated to determine how to reduce carbon dioxide emissions in many applications. Egg shells and various industrial wastes, which are recommended to use in the construction sector at an appropriately high rate, also cause serious environmental damage. Bottom ash (BA) and marble powder (MP) wastes are used today in civil engineering applications. In addition, it is important to increase the use of eggshells due to their rich calcium carbonate content. In this work, BA and MP wastes were blended with eggshells to produce cement paste composites. Two different sets of composites were prepared during this study. The composites were prepared with cement (80%), BA (20%), and MP (20%) wastes by weight with 0.3%, 0.75%, 1.5%, and 2.5% eggshell waste. The fresh (flow table), physical (dry unit mass, apparent specific gravity, and porosity), mechanical (unconfined compressive strength and flexural strength), and durability (water absorption, seawater resistance) tests were conducted. According to the experimental results, the composites can be classified as lightweight construction materials. The test results showed that 0.75% eggshell by weight of cement in bottom ash and marble powder can be used as an optimum value for better performance. The bottom ash mixtures groups are higher water absorption and porosity values when referring to the marble powder mixture groups. The highest compressive strength value was found at 56.03 MPa in the MP mixture group and 52.79 MPa in the BA mixture groups with these optimum eggshell combinations at 56 days. The MP mixture group showed better resistance to seawater when referring to the bottom ash blended mixtures. Laboratory-produced composites are possible candidates for cost-effective and environmentally friendly building materials. The eggshells have a promising alternative binder for concrete in the near future and they are utilized together with industrial wastes such as BA and MP in sustainable concrete construction.

Reinforcing effects of gypsum composite with basalt fiber and diatomite for improvement of high-temperature endurance

This review paper discusses about the different types of fibre used in concrete at different periods with the mix parameter details. This review enlightens the effect of industrial waste such as Bottom ash, Copper slag, Ferro-chromium slag, Ground granulated blast furnace slag (GGBFS), Steel slag, Stainless steel slag as a substitute in concrete. The elaborate study on its chemical composition and also the merits and demerits of using the slag are discussed. The experimental work carried out with mix proportion, w/c ratio of these industrial wastes in concrete is elaborately tabulated. The detail study reveals that more research work is required for the long term durability studies on the Copper slag, Ferro chromium slag, Steel slag and Stainless steel slag.

To develop a practical alternative to classic cement materials, alkali-activated materials were manufactured from industrial wastes (fly and bottom ash). Microstructural behavior of these blends was investigated through X-ray diffraction, scanning electron microscope, thermal analysis, Fourier-transform infrared spectroscopy and surface response methodology. Natrolite, phillipsite, and calcium aluminum silicate hydrate and sodium carbonate newly formed after alkali activation. Empirical ternary diagrams as well as modeling equations were united to predict the physico-mechanical evolution of the prepared specimens. The used model described well the evolution of the studied properties against the processing factors; temperature, NaOH concentration and curing time. The weight of the effect of each parameter was estimated and factor to factor interaction was considered. NaOH concentrations and ageing temperature had a considerable positive effect on density and mechanical strength, respectively. Water absorption and electrical conductivity were influenced differently by the factors, the electrical conductivity increases as the NaOH concentrations increase, and time and temperature decrease. The response surfaces and their results were correlated with the microstructure of the hardened samples. Overall, alkali activated binders with good engineering properties could be synthesized in the considered conditions. The optimal alkali activation conditions were ∼12 M and the corresponding final properties were as follows: 50 MPa for the compressive strength and 20% for water absorption while density was recorded at a 1.75 g/cm3 value.

Alkaline and alkaline-earth silicate glasses and glass-ceramics from municipal and industrial wastes

In this paper, a comparative experimental study was carried out to evaluate the effect of inclusion of different fiber types on strength of lime-stabilized clay. In this scope, a series of unconfined compressive strength tests were carried out on specimens including basalt and polypropylene fiber compacted under Standard Proctor effort (i.e., 35% by weight of soil). The effects of curing period (1, 7, 28, and 90 days), fiber type (basalt and polypropylene), fiber content (0, 0.25, 0.5, 0.75, 1%), fiber length (6, 12, and 19 mm), and lime content (0 and 9%) on strength properties were investigated. The results revealed that both basalt and polypropylene fibers increased the strength without inclusion of lime. For specimens including lime, strength of polypropylene fiber-reinforced specimens was remarkably higher than that reinforced with basalt fiber for lime-stabilized clay. However, greatest strength improvement was obtained by use of 0.75% basalt fiber of 19 mm length with 9% lime content after 90-day curing. Additionally, results of strength tests on specimens including 3 and 6% lime and 12-mm basalt fiber after 1, 7, 28, and 90-day curing were presented. It is evident that the use of 6-mm basalt fiber and 12-mm polypropylene fiber were the best options; however, efficiency of fiber inclusion is subject to change by varying lime contents. It was also observed that the secant modulus was increased by use of lime; however, strength of the correlations among secant modulus and unconfined compressive strength values was decreased by increasing amount of lime for specimens including both basalt and polypropylene fibers.

Destruction of decabromodiphenyl ether during incineration of plastic television housing waste at commercial-scale industrial waste incineration plants

In the present work, recycling of bottom ash from both industrial waste and municipal solid waste incinerators (MSWI) was investigated. In order to recycle bottom ash as raw materials for cement production, it is necessary to remove chloride, which causes metal erosion in reinforced concrete. Therefore, experiments for removing chloride were carried out by washing bottom ash in order to obtain efficient washing conditions. The following conditions were investigated: pH, type of solution, particle size, bubbling and temperature. Although pH is the most effective parameter for reducing Cl content in ash, using acid to lower pH is not an environmental friendly treatment considering wastewater treatment. It was found that CO2, bubbling in the form of microbubble is a proper treatment to decompose insoluble chloride as an environmental friendly treatment.

The geometrical and mechanical properties and chemical composition of different basalt and glass fibers have been investigated. Tensile tests were performed on short basalt fiber made by melt blowing, glass fiber and three different types of continuous basalt fibers made by spinneret method. The chemical composition was evaluated by plasma atomic emission spectroscopy. The geometrical and mechanical properties of continuous basalt and glass fibers were similar to each other in terms of diameter, tensile strength and modulus. Short basalt fibers had considerably lower average diameter and mechanical performance with relatively high standard deviation. The SiO2 and Al2 O3 content of basalt fibers showed correlation with tensile properties of fibers. Results revealed that continuous basalt fibers were competitive with glass fibers and short basalt fibers were weaker in terms of quality and mechanical properties. It was observed that the joint SiO 2 and Al2O3 content of basalt and glass fibers showed correlation with tensile properties of fibers.

In this paper, the physicochemical properties and hydration mechanism of cement-free binders developed from fluorogypsum has been discussed. The results showed maximum attainment of strength (38 MPa), low water absorption (<5%) and porosity (<10) with anhydrous calcium chloride and sodium sulphate activators. The enhancement in strength with hydration period was due to the conversion of fluorogypsum into gypsum through formation of intermediate unstable salt. The reaction products were characterised using X-ray diffraction and scanning electron microscopy (SEM) techniques. SEM studies showed the appearance of prismatic and needle-shaped crystals of variable sizes interspersed with anhydrate fluorogypsum plaster which make matrix dense and compact. This change in morphology of anhydrite plaster is responsible for enhancement in strength, reduction in water absorption and porosity of cement-free binders. The engineering properties of the construction materials for use in plastering, masonry works, concrete, blocks and tiles developed from this binder are reported.

The paper shows the results of studies of gypsum dispersed systems with the addition of waste production of basalt. Introduction basalt dust allows the physical and mechanical properties of the modified gypsum material. The effect of additives on the strength, density and water absorption of gypsum dispersions hydration hardening.

This research aimed to figure out the influence of fly ash mixture from the industrial waste at the temperatures of 150°C, 450°C, 750°C viewed from the strength and resistance of geopolymer paste. As a result, cement will be substituted by industrial waste like fly ash. This experimental research was conducted on the mix design of geopolymer concrete which was made by dimension with 2.5 cm in diameter and 5 cm in height from four mixture composition of fly ash and industrial waste i.e. 100% fly ash, 50% fly ash+50% bottom ash, 50% fly ash+50% sandblast, and 50% fly ash+50% carbide waste. Each mixture was tested in terms of porosity and compressive strength.In conclusion, in the mixture of 50% fly ash+50% Sandblast and 50% fly ash+50% bottom ash in 12 molars, 1.5 activator comparison can be used to substitute fly ash at high temperature. Meanwhile, the mixture of 50% fly ash+50% carbide waste in 8 molars, 0.5 activator comparison has very small strength remaining if it is compared to the mixture of fly ash and other industrial waste (Bottom ash and Sandblast). The performance of mixture paste of 50% fly ash+50% carbide waste was very vulnerable after being burnt. Consequently, it cannot be used as the main structure at high temperature.

Each year, China produces a substantial amount of municipal sludge, industrial waste (slag, fly ash, and desulfurized gypsum), and construction waste, while its recycling rate is low. If not disposed in a properly and timely manner, this inequity can have serious environmental impacts. This study aimed to prepare a new type of modified sludge material with high strength, low shrinkage, and low permeability by curing municipal sludge with industrial waste (slag, desulfurized gypsum, and fly ash) and powdered construction waste. At specific maintenance ages, the modified sludge material was examined for shrinkage deformation, water content, compressive strength, and hydraulic conductivity. The modified sludge material was also tested by scanning electron microscopy (SEM + EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) tests. The hydration products, micromorphology, and elemental composition of modified sludge were also analyzed at specific maintenance ages. These analyses revealed the mechanism of solidification of municipal sludge by industrial waste and powdered construction waste and the changes in the microstructure of the sludge. The results showed that the compressive strength of the modified sludge ranged from 3.83 to 8.63 MPa, volumetric shrinkage ranged from 2.12 to 12.68%, and hydraulic conductivity ranged from 1.65 × 10−8 to 2.21 × 10−7 cm/s after 28 d of maintenance. The active substances, such as SiO2, Al2O3, and CaO, in the industrial waste, powdered construction waste, and municipal sludge were subjected to a hydration reaction in an alkaline environment to produce dense blocks, agglomerates of C-S-H, ettringite, gismondine, and other hydration products. The compressive strength of the modified sludge increased, and its internal structure was dense.

Objectives: Utilization of steel fiber increases concrete strength and ductility however, the cost of steel fiber is high and ultimately leads to an increase in the cost of concrete. Basalt fiber is a new type of fiber with high strength and toughness and can effectively replace the place of steel fibers. In this paper, concrete reinforced with polypropylene fibers and basalt fibers was tested for its mechanical properties and compared with the same predicted through a simulated model created by the Artificial Neural Network. Methods: The percentage of polypropylene fiber was kept at 0.25%, and different amounts of basalt fiber were added as 0%, 0.25%, 0.5%, 0.75%, and 1%. Based on traditional testing methods compressive strength, tensile strength, and flexural strength of normal concrete, Fiber reinforced concrete and Hybrid fiber reinforced concrete have been found. To forecast the concrete qualities, the model was simulated after the datasets were trained using a neural network fitting tool. Findings: In comparison to concrete that had only 0.25% polypropylene fiber, a hybrid fiber-reinforced concrete mix including 0.5% basalt fiber and 0.25% polypropylene fiber demonstrated a 9.69% improvement in compressive strength. In comparison to the concrete made only of polypropylene, the mix containing 0.25% polypropylene fiber and 0.75% basalt fiber showed a 26.12% increase in flexural strength and a 39.25% increase in split tensile strength. The error percentage between predicted and experimental values is below 10%. Novelty: Utilization of basalt fiber in concrete is very rare and this proposed work focused on the hybridization of basalt fiber in the place of steel fibers, which is prone to corrosion and reduces the cost of material effectively. The concrete's flexural and tensile strengths were significantly increased by the addition of basalt fibers. The mechanical characteristics of hybrid fiber-reinforced concrete are well predicted by the simulated ANN model. Keywords: Basalt fiber, Polypropylene fiber, Artificial Neural network, Fiber reinforced concrete, Hybridization