Search

The life span of a structure depends on the strength and durability of concrete. The use of mineral admixtures in concrete plays a major role in achieving higher strength and durability characteristics. At present nanotechnology is being used in the concrete to decrease the permeability of concrete and also to extend the life service. Nanomaterials are extremely small in size which when used in concrete, improves the strength and reduces porosity. This study gives the characteristics of concrete when Nanosilica (NS) and Multi-Walled Carbon Nanotubes (CNT) were added to it. Manufactured sand was used as a fine aggregate in replacement of natural river sand. For conventional and nano-concrete, the durability characteristics were assessed by conducting water absorption, sorptivity, accelerated corrosion, and carbonation tests after 28 days and 90 days of curing. The formation of hydration products was studied through microstructural analysis by SEM and XRD. Closely packed concrete was achieved with the addition of NS and CNT. The permeability and porosity were reduced for nano-concrete because of the filler effect of nanomaterials.

Plastics are an increasingly important component of urban solid waste. The disposal of waste materials, such as used plastic bags, has become a major issue. The vast amount of waste plastic bags collected in the twenty-first century has posed significant challenges for their disposal. The amount of waste plastic in the home is substantial and growing. Our results indicate cement blocks are ideal for laying and finishing pathways and streets because they are easy to lay and finish. This study was carried out on experimenting the substitute materials in the mixture of cement blocks a component of building materials which is normally manufactured using the mixture of cement, fine aggregate and water, following a certain ratio. A series of three different percentages of plastics bags were added with the mix and certain quantities were replaced by quarry dust instead of Fine aggregate. Tests were done on the blocks to study its compressive strength, split tensile strength the water absorption percentage and acid test. Both the test compressive and split tensile tests were conducted on the seventh and 28th day. Based on the results acquired, for compressive strength tests on the 28th day, the result a good indication is that the blocks can be produced by replacing the cement and fine aggregate with utilizing the plastic for and effective way of 1:1 and 1:2, with 10& 20% replacing with quarry dust having strength 10.7 and 9.5 N/mm2 respectively Which is 165 more than the conventional type of blocks. Similarly the water percentage is also nil and very marginal in the same proportions. The decrease in weight is existed in all the samples tested the result is equal in all mix compositions. This is uniform rate implies block undergo certain abrasion. Conclusions were drawn for utilising the above composition in a suitable non structured places and minimizing the plastic waste.

Carbon Nano Tubes are strongest known materials known till now which can be ideally used in conventional concrete to tailor its functionalities. As water cement ratio governs the strength, serviceability and durability of concrete so its important to know the effect of Carbon Nano Tubes on basic properties of concrete. In order to analyze fresh and hardened properties of conventional concrete 0.5% Carbon Nano Tubes by weight of cement was incorporated in concrete mixes having water cement ratio 0.40, 0.45, 0.48.0.50 and 0.50. It was observed at 0.45 water cement ratio compressive, split tensile and Moment of resistance was greater by 8.89%, 28.9% and 5.33% respectively in comparison to Reference mixes while workability diminued by 38.40% and water absorption decreased by 0.03%. Also Coefficient of relationship R2 for water absorption and water-cement ratio of Carbon Nano Tube reinforced concrete was found as high as 0.97. Scanning electron microscopic analysis revealed dispersion of Carbon Nano Tubes and their bridging effect.

The housing problem in Tunisia has become more acute due to the high cost of construction materials, thus constituting a source of concern for the population. To resolve the crisis, upgrading abundant local materials has become a necessity. This paper aimed to assess the potential use of Jebel Menchar's geomaterial to develop compressed earth brick (CEB). Laboratory tests were performed to determine the physical, chemical and mineralogical properties. Series of destructive and non-destructive tests were carried out to characterize the properties of bricks based on their composition in terms of compressive strength, flexural strength, water absorption and ultrasonic testing. The results indicated that all of the bricks studied exhibited a compressive strength greater than 2.3 Mpa during the 28-day experiments, thus suggesting a high potential ability to reduce building material problems, while also providing the brick industry a useful and inexpensive new raw material with less CO2 emissions.

The construction industry is always in need of new technologies and products that improve technological characteristics. Alkali-activated materials appear as an alternative to reduce energy costs, improve technological properties and still present themselves as materials with the potential for incorporating industrial waste. The objective of this research was the development of roof tiles through the process of alkaline activation using ash from the kilns of burning of a red ceramic industry. After the process of processing the materials and their characterizations, prismatic specimens (115 × 30 × 20 mm) were made with the replacement of 0, 6.25, 12.5, 25 and 50% ash by metakaolin and subsequently separated into two groups, (i) subjected to curing at room temperature and (ii) subjected to curing at a temperature of 80 °C, in both cases with a curing time of 7, 14 and 28 days. After each curing period and group, the specimens were subjected to technological evaluation of water absorption, porosity, flexural strength and scanning electron microscopy. The results obtained demonstrate that the use of ash from ceramic waste, mainly replacing 12.5% of the metakaolin, promotes a reduction in water absorption and porosity, and an increase in flexural strength. The results obtained at 28 days in thermal curing are 44.05 MPa for 12.5% ash, much higher than the reference composition (16.02 MPa). The increase in strength happens due to the formation of tobermorite, due to the calcium present in the ash, and due to the formation of phases rich in potassium from the ash, such as kalsilite. Thus, it is concluded that the use of ash from ceramic waste is possible in the alkaline activation of roof tiles due to the occurrence of additional mechanisms of alkaline activation.

Mullite is one of the preferred aluminosilicates for both traditional and advanced ceramics. This paper reports the use of simplex-centroid mixture design to prepare mullite–glass ceramics by reactive sintering. The phase composition and technological properties of formulations containing kaolinitic clay, kaolin waste and alumina were investigated after sintering at 1400 °C. The sintering behavior was assessed by dilatometry. Microstructural analysis indicated the crystalline phases mullite, residual quartz, cristobalite, and α-alumina. A glassy phase was also identified as a matrix embedding mullite grains (as seen by X-ray diffractometry and scanning electron microscopy). In kaolin waste-rich formulations, a liquid phase sintering mechanism favored the densification process and the mechanical resistance. Highly significant statistical models allow correlating the concentrations of raw materials with linear firing shrinkage, water absorption and apparent porosity. Overall results stand out for the potential of using kaolin waste in the preparation of mullite–glass ceramics.

This study focused on the optimization of the production conditions of an ultrahigh expanded perlite lightweight aggregate-filled fly ash-based geopolymer composite and the determination of its product properties. The geopolymer matrix was synthetized using mechanically activated fly ash and an alkaline solution. In a systematic series of experiments, the effect of expanded perlite (EP) content, the compaction pressure and the compaction time on the mechanical properties of the lightweight composite were investigated. In the case of the optimal production conditions, the composites were characterized in terms of physico-mechanical properties, water absorption and microstructure. The composites produced under optimal conditions had an average uniaxial compressive strength of 246 kPa and density of 534 kg/m3 at 80% by volume EP content, and 264 kPa and 221 kg/m3 at 95% by volume EP content. Both the FT-IR spectroscopy and scanning electron microscopy results proved the formation of main geopolymerization reaction products in the matrix of the composite, as well its reaction with the lightweight aggregate.

The hydrogel sponges have prepared successfully from gelatin/chitosan (GEL/CTS) matrix with different polyols basing on scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analysis. The results indicate that the compressibility and thermal properties (thermal gravimetric analysis, TGA) were improved significantly with adding the different polyols [poly(vinyl alcohol) – PVA, and poly(ethylene glycol)-poly(propylene glycol)- poly(ethylene glycol) – PEPEG] into GEL/CTS matrix. Specially, the as-prepared hydrogel sponges with superabsorbent behavior were also investigated with the attained water absorption capacity to 605 ​g ​g−1 and 585 ​g ​g−1 for GCV_1/1/0.3 and GCE_1/1/0.3 sponges, respectively, as well as the excellent water absorption capacity in a wide range of pH and salt concentration. Hence, these studies demonstrated that the hydrogel sponges are concerned as potential and promising candidates to apply especially in the fields of biomedicine and hygiene.

Concrete is one of the largest consumer products all over the world. Concrete consumes large quantity of natural ingredients like river sand in the form of fine aggregate and crushed stone or gravel in the form of coarse aggregate. With due consideration for sustainable construction, the concrete can be minimized by utilizing the waste products from various industries as an alternative for components in concrete. This paper deals with reuse of industrial waste foundry sand and agricultural waste coconut shell in biased form for fine aggregate and coarse aggregate [Siddique, R and Kadri, EH (2011)]. From the mechanical properties of concrete containing both the waste products, the optimum replacement levels were arrived at 25 % and 15% for waste foundry sand and coconut shell. The durability properties such as water absorption, porosity, sorptivity and water permeability are found for improvised concrete and compared with normal concrete.

According to the latest studies, nanoparticles are the best additive materials to improve concrete's mechanical properties. Among these nanoparticles, Carbon Nanotubes (CNTs) are famous for their extreme tensile strength and flexibility. These particles can be used as a reinforcement to increase the mechanical properties of concrete. In the present study, the effects of using CNTs with different dosages were investigated on structural lightweight concrete’s mechanical properties. Structural Lightweight Expanded Clay Aggregates (LECA) were used in the mixture of Structural Lightweight Concrete (LWC) as a substitute for coarse aggregates. Along with LECA, CNTs as a partial replacement for cement with varied weight ratios were added to the lightweight concrete (0.02, 0.1, and 0.3 percent of cement weight). The effects of carbon nanotubes on fresh concrete performance, water absorption, compressive strength, tensile strength, and flexural strength of 7- and 28-day lightweight concrete were carried out. The results indicate that the presence of 0.02% of cement weight of CNTs increased compressive strength, tensile strength, and flexural strength of the 28-day-old lightweight concrete up to 29%, 44%, and 26%, respectively. Moreover, it reduced the water absorption of lightweight concrete by 28.3%. Utilizing more content of CNTs resulted in less mechanical properties. Having done experimental tests, nanoparticles and cementitious materials bonding have been visualized by Scanning Electron Microscopy (SEM) device.

Microbial self-healing is an innovative technology which repairs cracks in concrete by precipitation of calcite. The main focus of our research study was focused on evaluating the performance of synthesized microbial agent with Bacillus sphaericus (spore forming urelotic strain) of cell dosage 105 cells/ml in repairing cracks in fly ash concrete. The bio-based agent is added to cracks in fly ash concrete. The effectiveness of prepared bio- based agent in repairing the cracks in concrete was assessed by comparing with non-based agent prepared with cement, sand and water. The mechanical and water absorption property are evaluated. The compressive strength and water absorption of micro-repaired concrete was found to increase by 10% and 6 % in comparison with non micro repair concrete. Scanning electron microscope analysis of concrete samples was done to confirm formation of calcite. The analysis showed formation of calcite particle near the microbial cells. This confirms that the improvement in properties of concrete is due to formation of calcite particles due to biomineralization process. Use of Micro-based agent would lead to environmental and economical benefit. Over all the maintenance and repair cost could be reduced and also play a role in reducing green house gas emissions and help to develop sustainable concrete.

A novel ceramic composite has been obtained by introducing polyvinyl alcohol in magnesium-based chemically-bonded ceramics and exploiting the cross-link reaction with glutaraldehyde during setting. The properties of the obtained material and the interaction of the polymer with the cement reaction have been investigated. Several beneficial effects were observed. Namely, an extension of the working time, a reduction in the water sensitivity, a decrease in the rate of the heat evolution during hardening. The latter has been ascribed to the intervention of surface adsorption processes, which hindered the dissolution of MgO, as well as the nucleation and growth of the magnesium phosphate products, in concert with the film forming ability of the polymer. Thanks to the complementarity of their mechanical properties, the cement and the additive operated in a synergistic fashion, allowing for the obtainment of a material possessing higher strength and better elastic properties. Three-dimensional quantitative image analysis from synchrotron X-ray microcomputed tomography evidenced the development of a more compact microstructure, comprising a higher number of crystals of smaller size. As a consequence, the pore network exhibited a higher fraction of small pores and lower pore connectivity. These characteristics contributed to hinder the water absorption, as confirmed by the fluid transport simulations within the volume. The observed correlation between the solution pH and the polymer cross-link density offers the way to effectively modulate the material performance by acting on the chemical environment thanks to its compatibility with the cross-link reaction.

The present study deals with the utilization of Groundnut Shell Ash (GSA) as a partial replacement for fly ash in making unburnt fly ash bricks. The percentage of GSA was varied from 10% to 33% in the manufacturing of bricks. Various tests such as specific gravity, bulk density, SEM, EDX, compressive strength, water absorption and efflorescence tests were conducted to analyse the effect of GSA in fly ash bricks. GSA when used in the making of unburnt bricks gives a satisfactory result in terms of its compressive strength. The strength obtained under optimum combination was found to be nearly equal to the prescribed value for first-class bricks. Water absorption was found to be 12.17% and efflorescence was found to be 8% which is well within the prescribed limit as per Bureau of Indian Standard. From the test results it is concluded that, the maximum optimized compressive strength is obtained for a combination of 25% GSA, 10% Fly Ash, 25%lime, 3%Gypsum and 37%Quarry dust. The GSA brick will be a commercially viable building material and also cheaper as it is abundantly available. Hence, a sincere attempt was made to find innovative, durable and economic alternative construction material in the form of brick by utilising the Groundnut Shell Ash.

Nowadays concrete and mortar demand as construction materials has been surged in market due to the exorbitant augmentation of the construction industry. Cement and fine aggregates (like river sand, pit sand etc.) are consumed in a large quantity to produce the mortar for various uses. In this venture, the cement and natural sand is been replaced with the soda-lime glass and the properties of mortar has been characterized for this replacement. Various proportions adopted for the cement replacement by weight 0–20% and natural sand replacement by weight are used 0–30% at 5% interval. The influence on the workability, density, water absorption, mechanical strength, drying shrinkage and Alkali Silica Reaction (ASR) expansion are assessed. Outcome of the investigation reveals that the dose of soda-lime glass replaced with cement and natural sand plays an important role to determine characteristics of cement mortar. Mortar made with Glass powder (GP) at 15% replacement with cement and Glass sand (GS) at 25% replacement with natural sand have highest mechanical strength. Water absorption and density reduced by using soda-lime glass. Drying shrinkage mitigate by using waste glass. ASR expansion has reduces due to smaller particle size of glass. The pores refinement and porosity decrement occurs due to the calcium hydroxide (Ca(OH)2) and glass powder reaction, this is a pozzolanic reaction that produces calcium silicate hydrate (C-S-H) gel.

Because of their high strength-to-weight ratio, composites outperform traditional materials. Natural fibers are increasingly being used in composites due to environmental concerns. Their hygroscopic character, on the other hand, has a negative impact on the mechanical properties of the composites. The need to analyses the water uptake characteristics of natural fiber hybrid composites has arisen as a result of composites' use in decking, flooring, and outdoor facilities. The objective of this paper is to study the water absorption behavior and observed that banana/glass fiber composite keeps on increasing. The conclusion is that banana fiber absorbs more water than kenaf/glass fiber composites, and there are numerous causes for trapping of natural fiber water consumption.

Mostly, agricultural residues and fibers are incinerated or dumped into the land after cultivation. Disposal of these waste not only occupy more useful space in land but also spoiled energy resources. It causes pollution to the environment, release of greenhouse gases, etc. Lignocellulosic fibers are rich in cellulose which is abundant in nature. In this work, Banana fiber which was extracted from the bast of the plant is used to make an alternate for synthetic fibers. The polyester based composites were manufactured by with different weight concentration of fibers from 1 to 10%. Tensile and water absorption values of composites were conducted as per the ASTM standards. When the fiber addition increases, water absorption properties also increased due to the characteristics of lignocellulose fibers. From the results, it was understood that the obtained composites can be used in various commercial and bio medical application.

Environmental benefits and amazing performance can be obtained by utilizing palm oil fibres and kenaf fibres which illustrate colossal potential in fibre reinforced composites. An investigation has been made to determine the effects of alkaline treatment on water absorption and swelling behaviour of palm oil fibre composites as well as kenaf fibre composites. Untreated and treated natural fibres and were prepared in random orientation with different volume fraction of palm oil fibres and kenaf fibres; 30%, 40%, and 60. All the treated fibres were treated with 1 w/v% and 5 w/v% of sodium hydroxide concentration. Water absorption test was performed by immersing the sample in the distilled water periodically measuring the sample weight. Thickness swelling test was carried out by measuring the thickness of the specimens before and after soaking in the distilled water within certain period of time. All specimens were observed under Scanning Electron Microscope (SEM) to study the fibre morphology. TPOF_30_5SH achieved the least percentage of water absorption (1.44%) when it was compared with the UPOF_30 and TPOF_40_1SH. UPOF_60 shows the highest percentage of thickness swelling (8.96%). TPOF_30_5SH and TPOF_40_5SH show reduction of water absorption when they were compared with UPOF_30 and UPOF_40 respectively. All the treated kenaf fibre composites with 5 w/v% sodium hydroxide concentration such as TKF_30_5SH, TKF_40_5SH and TKF_60_5SH show improved result of thickness swelling. Materials covering the surface of palm oil fibres and kenaf fibres were more effectively removed with 5 w/v% sodium hydroxide than by treatment with 1 w/v% sodium hydroxide while observing under SEM.

Soil Reinforced Blocks are the new attempt in which a soil block of definite size and shape is produced by incorporating the Reinforcement into the Stabilized Soil by wrapping the Geomembrane around the soil block with the proposal of applying it as a Foundation Bed. Red soil is primarily stabilized by using Portland Cement and Steel bars are used as Reinforcement, by using these materials Soil reinforced blocks are constructed which is similar to the construction of Reinforced Concrete Columns in the form of solid blocks. The main objective of the work is to produce an Engineered Efficient Structure in the form of soil reinforced blocks to provide a Solid High Resistance Foundation Platform to the structure by placing these Soil Reinforced blocks in the ground where Foundation Soil has Low Bearing Capacity. After the construction of Soil Reinforced blocks, these are tested against Compression, Bending Tension, Triaxial Shear, UCS, CBR, and Water Absorption. To avoid the Saturation or Entry of Water into the Soil Reinforced blocks a Geo-Synthetic material named Geo-membrane is used. A Geo-membrane is a Synthetic material with the primary function of Obstructing Moisture and it will be wrapped around the Soil Reinforced blocks. A Geotechnical Structure possessing the Good Engineering properties are the Expected Possible Outcomes.

In the age of sustainability, it is necessary to prevent the depletion of natural resources to maintain needs and ecology. Hence, in the process of manufacturing mud and fly ash bio-bricks, materials like fly ash and bacterial solutions (Bacillus Megaterium and Bacillus Subtilis) are widely used. The experiment was carried out at various pH levels (basic, acidic, neutral) and at different temperatures (4, 31, 60 °C) with two different kinds of water (lab grade, groundwater) to find the optimum mix proportion of a brick. Bricks were cast by the MICP method where bio-mineralization (a process that converts CaCl2, urea, and bacteria into CaCO3) takes place. An experimental program has been carried out at various ages of bricks in order to determine the physical and mechanical properties of bricks, such as compressive strength, water absorption, hardness, size, shape, and color. The experiment results are used to determine the effect of bacterial solutions and fly ash content on the unburnt brick’s properties. The bricks tested showed comparatively better properties than the conventional and hence they are good to be used in temporary construction.

This paper investigated the effect of rice husk ash (RHA) on chloride permeability, water absorption, and permeable pore space of cementitious mortar. It was observed that the permeability, water absorption, and permeable pore spaces of mortar mixtures having rice husk ash as partial replacement of cement decreased as the amount of rice husk ash increased while the compressive strength increased. The reduction in chloride permeability, water absorption, and permeable pore space ranged between ∼3 to ∼52, ∼2 to 10%, and ∼2% to 18% with 4% to 12% RHA dosages without RHA mixture. In addition, linear co-relation exists between water absorption and permeable pore space and permeable pore space and charge pass with a coefficient of correlation of 0.93 and 0.90, respectively; quadratic polynomial co-relation exists between compressive strength and water absorption and compressive strength and permeable pore space.

Steel filings are primarily composed of steel. These steel filings are produced by grinding, shaving and cutting the various steel in the mechanical workshop or factories. The steel wastes are disposed into the landfills, rivers and oceans thereby increasing pollution. To reduce these wastes reaching the landfill sites, one solution is to reuse them in construction. There have been some studies on the strength of concrete made with steel filings, however, no study has been reported on the durability. The purpose of this research was to evaluate the durability of concrete made with steel fillings as a replacement of fine aggregate. In the current study, different replacement levels of steel fillings such as 0%, 10%, 20%, 30% and 40% have been used in the making of concrete. Cube samples were tested for durability after normal curing for 28 days. It was found that the cube looses its workability and slump, when the percentage of steel filing were increased beyond 40% as replacement of fine aggregate. The water absorption increased with increasing percentage of steel filing and the sorptivity tests showed that the weight of capillary rise of water increased with the increasing percentage of steel filing due to the increased porosity of the concrete. This type of concrete may be used for the pavement and parking lots, where there is a problem of water logging, as it would allow the water to pass through it and may help in recharge of the ground water.

The current study mainly aims on the usage of waste coarse slag aggregates (CSA) to prepare coarse slag aggregate concrete (CSAC). The waste slag aggregates are the by-products mainly obtained from the iron and steel industries. These wastes are mostly disposed off into the landfills and the newer alternative method of disposing are being researched. Also, the increasing rate of construction has resulted into the diminishing of natural raw materials. The present paper focuses on incorporating CSA as the replacement of 20 mm natural coarse aggregates to prepare CSAC for various volumetric replacement of 20%, 40%, 60%, 80% and 100%. Cube and beam samples having different percentages of CSA were casted to undergo the experimental analysis. The fresh, mechanical and durability parameters has been studied by performing workability, density, compressive strength, split tensile strength, ultrasonic pulse velocity, water absorption and water permeability tests, for the in-depth analysis. The outcomes from the experiments has shown decrease in the strength and durability properties for increasing count of CSA. Decrease in compressive and split tensile strength of 39.08% and 37.50% respectively was observed for 100% CSA replacement. In case of durability properties, the penetration depth has increased up to 69.84% for the 100% CA replacement sample. However, a very marginal decrease in the values were observed for the replacement content up to 40%. The study concluded that the utilization of slag aggregate is a sustainable approach by preserving the naturally available raw materials and also construction can be made economical.

In this work, the hybrid natural fiber composites (NFCs) were prepared using a standard hand lay-up technique from Banana fiber (B), Sisal fiber (S), and sawdust (SD) with different compositions viz. S-I (B 60%–S 20%–SD 20%), S-II (B 80%–S 5%–SD 15%) and, S-III (B 80%–S 15%–SD 5%) bounded with 80% epoxy resin LY556 and hardener LY953 in the 4:1 ratio as per ASTM standards. All the specimens were made with proper composition of 20 wt% of reinforcing materials and 80 wt% of the matrix material. The mechanical (tensile strength, compressive strength, flexural strength, and impact strength) properties and Brinell hardness of prepared specimens were conducted according to ASTM standards. The tensile, compressive, flexural, and impact strength, as well as Brinell hardness of the prepared NFCs, were found to increase with the increase in sawdust content in the epoxy matrix. Further, an improvement in the water absorption property was registered with the increment of sawdust content in the banana-sisal/epoxy composite. The value of dielectric permittivity increased while that of tangent loss decreased with increasing sawdust content. The improved mechanical, dielectric as well as water absorption properties and better Brinell hardness, foreshadow the industrial promises of the present NFCs a better alternative for synthetic fiber-reinforced composite materials.

The effects of adding iron oxide to ceramic glaze formulations were studied in this study. Iron oxide was added in different weight ratios into the reactive transparent glaze, reactive opaque glaze, and transparent glaze formulations. The iron oxide content in the glaze composition, the coloring mechanisms, the phase distributions, and surface properties at temperatures of 950–1000-1050-1200 °C in the oxidation firing medium were investigated. Scanning Electron Microscopy (SEM) to determine the microstructural and morphological characterizations of the test glazes, X-Ray Diffractometry (XRD) to determine the crystallographic properties and phases, and X-Ray Fluorescence (XRF) analyses to determine the elemental and chemical composition were performed. In addition to these, surface images were examined with Digital Microscope (DM) and Commission Internationale de l'Eclairage (CIE) L*a*b, and water absorption values were compared. In addition, taking into account environmental factors, a comparison of ceramic glazes with the same amount of waste iron oxide was also performed for same purpose. As a result of the studies, it was observed that the addition of iron oxide and/or waste iron oxide did not have a negative effect, and coloring effects on the glaze layer were observed at different rates and firing temperatures.

The main components of concrete are cement and river sand (R-sand). Due to excessive production of cement, CO2 emission also increases which causes air pollution. On using R-Sand, large scale depletion of natural sources creates environmental problems. In view of the increasing national and global consensus on the environmental protection, the governments have put restrictions on mining of R-Sand from the river beds. To overcome these problems, there is a need of cost effective alternatives materials so as to make the construction sustainable without compromising its quality. In the production of Self Compacting Concrete (SCC), fly ash (FA) is utilized as an additional cementitious ingredient, which improves its performance. It solves the problem of FA disposal and environmental pollution too. The manufactured sand (M-sand) is also an alternative material which may solve the problem of shortage of R-Sand, if found suitable. In this study, M-Sand and FA were incorporated in the preparation of a sustainable SCC. After optimisation of FA and M-sand doses in the final mix, two types of SCC mixtures were developed: M-1, which consisted of 100% OPC + 100% R-Sand, and M-2, which consisted of 80% OPC + 20% FA + 50% R-Sand + 50% M-sand. Fresh properties of all SCCs were determined as per EFNARC/BIS recommendations. For destructive testing standard size specimens were cast to determine desired strengths after curing in tap water for 90 days. Rebound Hammer (RH) and Ultrasonic Pulse Velocity (UPV) were utilised in Non-Destructive Testing (NDT) to determine the strength, homogeneity, and integrity of both SCCs. Further, the water absorption of the specimen was measured up to 90 days. XRD analysis was also performed.

This study focus on the physical characterization of short roselle fibre polymer composites. Short roselle fibre composites with 10%, 20%, 30% and 40% fibre content by weight were produced using the hand lay-up technique. Composite’s physical properties like density, void content and water uptake capacity were obtained as per ASTM standards. The void content of the composites ranges from 1.28 to 6.71%, which is quite low for short and randomly oriented composites. The saturation in water uptake was observed after 7 to 8 days of water immersion. The water uptake capacity of the roselle fibre composites increases with an increase in fibre content. It indicates the composites with the lower fibre content yield a higher resistance to water absorption.

Waste is a common ingredient in Malaysia that has to do with man-made waste. Waste materials can be abundant in landfills without any profit. Waste materials can be harmful to the environment as well as to human health. One of the most abundant wastes is coal combustion ash from coal-fired power plants. In addition, the most common material used in the construction industry is brick. Bricks have been used for non-polluting structures and must be made of durable materials. The common material used for bricks is clay, sand and cement. All these ingredients are derived from natural resources. The depletion of natural resources has been a cause of concern for many. Therefore, this paper focuses on the development of bricks from coal terms of mechanical properties. The density, compressive strength and water absorption capacity of bricks made from coal ash were investigated after curing for 7, 14 and 28 days. The results show that the density of bricks made from coal ash is low, while the compressive strength meets the requirements and is 10.25 MPa and 8.67 MPa higher than control concrete, respectively. For the crushing value, the coal ash was compared with the coarse aggregate to meet the requirements of the test. The result shows that the coal is 34.6% higher than the natural aggregate. In conclusion, the use of coal ash in the production of bricks is a promising long-term option for the production of bricks.

Plastic waste is accumulated in recent years, causing environmental problems, particularly in developing nations. Recycling this waste as building materials is considered as a feasible solution to the environmental issue, but it is also a feasible solution to the issue of building economic design. This research aims to study the possibility of using plastic waste in the manufacture of unconventional bricks that are light in weight, environmentally friendly, inexpensive, and as an alternative to traditional bricks made from fossilized clays for use in the construction industries. In this paper, we use the remnants of medical syringes made of low-density polyethylene and two types of additives were added sawdust and sand in different proportions. The melting and moulding process was used in manufacturing. Testing has been conducted to identify hardness, density, water absorption, compressive strength and also to determine morphology properties by FTIR and SEM. The results showed that bricks made of plastic and sawdust gave a high compressive strength of 66Ϻpa at 20% of sawdust higher than bricks made of plastic and sand with a value of 61Ϻpa at 60% of sand. In both cases, they gave a higher compressive strength than ordinary bricks, as well as a very low absorption rate. The density was very low, especially with sawdust, where the highest value was 0.8985 g/cm3of pure polymer, and for sand, it was 1.4321 g/cm3 at 60% of sand and it gave good hardness values. The FTIR results showed that there is no chemical reaction, but only a physical reaction between the polymer and the additives, and through SEM, it was observed that there is homogeneity between the polymer and the additives. As a result, the study presents a new line of investigation into the sustainable recycling of the circular economy of waste thermoplastics.

As the population around the world is on the rise so to meet consumer's needs a large amount of solid waste is generating and it needs large landfill sites for disposal of this waste. Alteration of this solid waste into other alternative resources will reduce the load on non-renewable resource materials and this can help in solving the landfills problem. Numerous studies have drawn attention to the usage of solid waste in concrete production, which is an imperative material for construction. Specifically, those that can replace fine aggregate because these days many states have banned the use of river sand so researchers all over the globe looking for a suitable material that can replace river sand and also provide sustainability with better strength results. In this study, bone china cup plate-type ceramic waste powder was utilized as a fine aggregate. Ceramic waste powder (CWP) creates environmental degradation and the use of CWP in concrete as a substitute for natural resources would have a positive result on the environment. In this study, the sand was replaced partially with CWP at replacement levels of 0%, 10%, 20%, 30%, 40%, and 50% by the weighted amount of sand. To evaluate various properties of SCC mixes with CWP, various workability tests (i.e. slump flow, v-funnel, j-ring, and l-box) were performed in a fresh state of concrete, while compressive strength, ultrasonic pulse velocity, flexural strength, and water absorption tests were computed to measure the hardened characteristics of SCC mixes. In SCC mixes, the CWP confederation showed an improvement in mechanical strength of concrete at the 20% CWP placement stages and a decline above 20% CWP replacements in all strength characteristics.

Natural fibres now a days replacing the conventional structural materials such as Aluminium, steel, wood etc. with their excellent weight to strength ratio and with their high mechanical properties. In this present investigation hybrid composites were fabricated using Hand layup process using the natural fibres such as Banana, Coconut, Jute and Cotton fibres reinforced with Polyethylene at different weight proportions of 5, 8, 10, 12, 15, 18, 20 wt%. Tests such as water absorption, flexural rigidity, tensile, hardness and few other mechanical tests were conducted on the hybrid natural fibre reinforced composites. Among the hybrid composites the coconut fibre with 20 wt% and banana fibre with 18% shows high tensile strength with 56.4 N/mm2 and 54 N/mm2 and flexural strength. Water absorption is less in the hybrid composite with coconut and cotton fibres as reinforcements and gains mass of 5gm and 7gm.

Nowadays, the accumulation of various waste products is increasing day by day. So there is a great need for their proper disposal, without harming the environment. Moreover, due to the limited availability of natural resources like fine aggregates. There is a need for alternative building materials. The study's primary goal was to find an alternative, effective disposal method of dry sewage sludge of wastewater treatment plants as a building material. The possibility of using dry sewage sludge in concrete was assessed in this study. Various properties, like workability, compressive strength, ultrasonic pulse velocity, split tensile strength, water absorption, and cost-benefit analysis were reported in the study. According to the study, utilizing 5% of dry sewage sludge as a fine aggregate is possible without having a significant negative influence on concrete characteristics. With the use of dry sewage sludge, the manufacturing cost of concrete can be reduced by 1.63%.

Ultraviolet (UV) radiation is one of the most common methods for sterilizing materials with suspected biological warfare agent contamination. In this study, UV laser sterilization of ceramic tiles was investigated as a method for destroying Bacillus atrophaeus spores. The effects of UV irradiation were evaluated as a function of water absorption (porous and vitrified), tile color (black and white), and surface brightness (matte and glossy). Spores were loaded onto the surface of each tile and irradiated with a 266-nm UV laser. The irradiated spores were then removed by scraping with a razor blade and cultured in an agar plate for 24 h. The sterilizing effects of the UV laser were greater on the vitrified (group BIb) tiles than on the porous (group BIII) tiles. In addition, sterilization was more effective on white and matte tiles than on black and glossy tiles, respectively.

In order to avoid the energy consumption of dewatering and dust pollution in the preparation of non-sintered lightweight aggregates from dredged sediment, a new low-dust process of preparing non-sintered extruded wrap-shell aggregates (TH-WSLAs-W) by extrusion granulation is proposed and applied to produce TH-WSLAs-W baking-free bricks (TH-WSLAB-W). The basic physical properties (cylinder compressive strength, bulk density and water absorption) and microstructure of TH-WSLAs-W was explored. It shows that the curing agent will form a hydrophobic gel film around the sediment particles and form a network structure, which enhances the cylinder compressive strength (6.7 MPa) and frost resistance of TH-WSLAs-W. In addition, the interfacial transition zone among TH-WSLAB-Ws was studied by scanning electron microscope. It found that the micropore structure endow the TH-WSLAs-W with excellent water absorption and drainage property, promoting the hydration of cement, promising the integration of aggregate and cement, and its compressive strength reaches 20.5 MPa.

Present study aims to explore the effect of sintering temperature and dwelling time on the characteristics and morphological structure of lightweight aggregates made from dry sewage sludge and waste glass powder. The mixtures were sintered at temperatures from 1100 °C to 1200 °C at a heating rate of 10 °C/min with a dwelling time of 10, 20, and 30 min to produce lightweight aggregate samples. The thermophysical behavior of the mixtures and the physic-mechanical properties (including water absorption, particle density, and compressive strength) of the obtained lightweight aggregates were studied. The microstructure of the lightweight aggregates was also analyzed using X-ray micro-computed tomography. Results indicate that increasing the sintering temperature or extending the dwelling time will reduce the particle density and compressive strength of lightweight aggregates. Moreover, the sintering temperature and dwelling time show a considerably influence on the pore structure of lightweight aggregates, which is strongly related to the physical characteristics of the lightweight aggregates. The lightweight aggregates obtained at optimized sintering temperature of 1180 °C with an optimal dwelling time of 10 min show water absorption of 1.01%, particle density of 0.78 g/cm3, and compressive strength of 7.10 MPa, thereby meeting the standard requirement of GB/T 17431.2–2010.

The disposal of waste vehicle tires is an environmental and health problem, as their recycling is very difficult. One of the effective ways of recycling is using these tires as partial replacement of Portland cement in construction industry. In this study, a systematic experimental study (by making 810 laboratory samples) is performed on concrete made with finely ground rubber (GR) and metakaolin (MK) as partial replacements of cement to investigate the compressive strength, splitting tensile strength, flexural strength, water absorption, and dry unit weight. The main goal of this study is to achieve the optimal proportions of concrete incorporating GR and MK by maximizing mechanical strengths while minimizing the water absorption (WA) of concrete. To do so, 7 concrete mixtures containing GR are produced with 3 different cement contents: 350, 400, and 450 kg/m3 in conjunction with 2 different water-cement ratios: 0.45 and 0.50. Also, 1 concrete mix is used to optimize the concrete with hybrid blends of GR and MK by employing the response surface methodology (RSM). GR and MK are applied as partial replacements of Portland cement in ranges of 0–30 vol% and 0–20 vol%, respectively. The results show that the use of GR and MK in concrete has a significant effect on its mechanical and durability properties and, thus, reduces the cement consumption which can contribute to decreasing the negative impacts of cement production on the environment. According to the optimization results, 4.2% and 19.5 vol% replacements of cement with GR and MK, respectively, can be considered as the optimum mixture compositions of hybrid concrete to maximize compressive and splitting tensile strengths by about 1–4% and 6–8%, respectively, while minimizing WA by about 48%. Depending on the flexural strength results, the amounts are changed into 1.8% and 14.7% while the flexural strength increases by about 11%.

The world's steel production has been closer to two billion tons per year and the blast furnace slag (BFS) is the maximum solid waste during the iron-smelting and steel-making process. To conserve energy and reduce emissions, on-site treatment of BFS to produce high value-added products has become a trend. In this study, the foamed glass-ceramic (FGC) is prepared by using BFS and waste glass as the base materials and the residual heat of pre-heated furnace as the heat source to simulate the high temperature industrial waste heat. The optimal FGC shows a low apparent density of 0.67 ± 0.052 g cm−3, a high porosity of 61.49 ± 1.90%, a good compressive strength of 3.18 ± 0.11 MPa, an excellent strength-to-density ratio of 4.75 MPa cm3 g−1 and a relatively small water absorption ratio of 7.05 ± 0.95%, which could completely satisfy the application requirements in the field of building construction. Combined with the SEM, XRD and TEM results, it can be found that the new formed CaSiO3 crystals plays a bridging role between the glass phase and the ceramic phase pre-existed in the BFS, which could effectively reinforce the compressive strength. This study provides a simple and feasible route to treat solid waste by using industrial waste heat and offers a new idea to solve the similar resources, energy and environmental issues.

In order to develop a highly efficient, simple-preparation and renewable explosion suppressant of composite powders, the superfine NaHCO3-shell powder (S-S) composite explosion suppressant was prepared by one-step method with airflow crusher to fulfill the mechanical dry coating of shell powder by NaHCO3, which solved the contradiction between dispersion and suspension force of explosion suppressant particles. The composition optimization and performance test of S-S composite explosion suppressant were carried out with the use of 20 L explosion tank and large tubular coal dust characteristics identification instrument. The results show that when the shell powder particles are coated with NaHCO3, the overall water absorption performance of the powder is reduced, the particle agglomeration phenomenon is weakened, and the dispersion is obviously improved. With the increase of NaHCO3 ratio, the ignition sensitivity of coal dust decreases, and the time to reach the first explosion Pmax is gradually delayed, and both Pmax and (dP/dt)max decrease. With the following explanations: NaHCO3 has a significant effect on reducing (dP/dt)max due to its chemical reaction, while shell powder is beneficial to reducing the Pmax due to its physical barrier effect. The suppression effect of S-S composite explosion suppressant on coal dust explosion is far better than that of pure NaHCO3 or shell powder.

Here a starch and starch hydrogel nanocomposite and superabsorbent cotton fabric was fabricated and characterized. The optimized starch hydrogel nanocomposite was synthesized by using 0.008 M potassium permanganate, 0.7 g starch and 0.6 M sodium hydroxide at 50–55 °C. potassium permanganate as a strong and inexpensive oxidizing agent were used to potentially nano cross-link the starch molecular chains and graft the starch to cellulose molecular chains along with synthesizing manganese dioxide nanoparticles (MnO2) to further obtain antibacterial, antifungal and photocatalytic properties. The stability of products in water and the water absorption indicated the highest water content of 800% for the optimum sample. The same materials and conditions were also applied to the cotton fabric to produce a superabsorbent fabric. The simple one-step synthesis procedure, in-situ production of nanoparticles, cost-effectiveness and having desired features including photocatalytic, antibacterial properties of 93% against S. aureus, and biocompatibility make the starch hydrogel nanocomposite a suitable candidate for various applications such as agriculture, medical, textile engineering and water treatment.

The production of ceramic tiles with larger sizes and reduced thickness has increased the challenge of producing high-quality ceramic tiles in short single-firing cycles. For porcelain tiles, the pressing step is of upmost importance for the microstructure of the green bodies. The particle size distribution, mineral composition of the pastes and porosity before firing define the water flow during the decoration process. Hydro deformation is the curvature of unfired ceramic tiles caused by water absorption during the decoration step before firing. In this work, the hydro deformation is studied in function of tile thickness, compaction, and clay composition according to a 2K factorial design. Two compositions of porcelain tiles (glazed and polished) were pressed at two thicknesses (3–6 mm) and pressing pressures (35.5–49.8 MPa) forming ceramic tiles with 55 × 110 mm² of surface area. Chemical (XRF), mineralogical (XRD), thermogravimetric (TG), specific surface area (BET), granulometric, bulk density, and porosity analyses were performed for the green tiles of both compositions. To simulate the hydro deformation during the decoration step, the curvature (mm) of the tiles was studied within a 0–180 min interval. The water absorption rate through the surface (g.m−2·s−1) of the tiles in an interval of 0–180 s was studied as a function of thickness, pressure and porcelain tile composition. As a result, the thickness of the tiles can change the curvatures from concave to convex. Pressing conditions and composition of the tiles can change the water absorption rates. Porcelain tiles with higher content of clay minerals develop convex curvatures. For tiles with lower content of clay minerals, concave curvatures were developed.

Due to the production of industrial slags in massive amounts, there is a high demand for recycling these slags and avoiding their dumping in landfills. This article aims to recycle industrial slags in brick manufacturing and investigates the performance of fired clay bricks incorporating different kinds of industrial slags such as granulated blast furnace slag (GBS), ferrochromium slag (FCS), and steel slag (STS). For this purpose, two different dosages of slags (i.e., 10 and 20 wt % of clay) and two different firing temperatures (i.e., 1000 and 1100 oC) were considered. Various physical, mechanical, and durability tests were performed to evaluate the properties of bricks incorporating industrial slags. Results show that the compressive strength of the bricks incorporating industrial slags are well above the minimum compressive strength limits of bricks as per different building standards. The bricks incorporating industrial slag can be classified as load-bearing bricks for structural applications in accordance with the ASTM C469 standard. An increase in the porosity of bricks is observed with the addition of STS. However, reduced porosity is observed for bricks incorporating FCS and GBS than traditional bricks. Based on the water absorption and efflorescence test results, bricks incorporating industrial slags can be used as severe weather resistant bricks following ASTM C62 standard and slight efflorescence bricks per ASTM C67 standard. The amounts of heavy metals in the leachates of bricks are observed below the specified limits of the Environment Protection Authority. SEM images and EDS analysis of bricks are also supporting the results of this study. Based on the results, utilizing industrial slags in brick manufacturing can help recycle the abundant industrial wastes and develop the fired clay bricks with desired properties.

Concrete in service is unpredictably exposed to fire attack, while the properties of recycled concrete aggregate (RCA) and recycled concrete powder (RCP) from demolishing fire-damaged concrete have received little consideration until now. This work investigates the effects of fire-damaged concrete waste on the properties of its preparing RCA, RCP and newmade concrete. The results show that the water absorption of RCA from 300 to 800 °C fire-damaged concrete is 39.1–169.5% higher than that of ordinary RCA from waste concrete without induced damage. The properties of concrete decrease as RCA incorporates, and decrease following the growth of undergoing temperature on the fire-damaged concrete and its RCA. The compressive strength of concrete including 100% RCA from 300 to 800 °C fire-damaged concrete is 11.4–41.4% lower than that of concrete with 100% ordinary RCA, and the transport properties of concrete including fire-damaged RCA are higher than those of concrete with ordinary RCA. There is no obvious difference in the mineral composition of RCP made from 20 to 600 °C fire-damaged concrete, but new active components appear in RCP made from 800 °C fire-damaged concrete. The activity indexes of ordinary RCP and the RCP from 800 °C fire-damaged concrete are 72.6% and 90.4%. The properties of concrete decrease as RCP incorporates, while the properties of concrete incorporating RCP from fire-damaged concrete are better than those of concrete incorporating ordinary RCP. The compressive strength and absorption coefficient of concrete including 30% RCP from 800 °C fire-damaged concrete are 20.9% higher and 24.9% lower relative to concrete with 30% ordinary RCP.

Hypothesis The absorption capacity and kinetics of nanocellulose foams are controlled by the surface charge of the fibers, which affects swelling and determine the porosity and structure of the network. Experiments Absorption kinetics were quantified at time scales ranging from fractions of a second to minutes. The mass absorption rate as well as the area profile for the liquid stains were simultaneously measured. Findings The absorption profile followed a three-stage mechanism: wicking, transition and fiber swelling. Absorption of fluids differing in ionic strength revealed the critical role played by electrostatic forces. Nanocellulose foam absorption capacity is 25% higher for water than for 0.9 wt% NaCl solution. The absorption kinetics of nanocellulose foam are also tuneable by modulating the surface charge. High surface charge nanocellulose foams have slower absorption in water than their low surface charged analogues. This behaviour is driven by the lower pore sizes developed in high surface charge foams, as determined by X-ray CT. Small Angle X-ray Scattering revealed structural homogeneity of high surface charge foams upon absorption of water due to high fibrillation and fiber swelling.

Neem fibers are traditionally added as reinforcements in adobes. Laboratory experiments including, compressive strength, three-point bending strength, water absorption, erosion and thermal conductivity were carried out on adobes made with soil and reinforced with two neem fibers types (straw and leaves) at 0, 1, 2, 3 and 4%. It has been found that mechanical, thermal, and durability properties of adobes were globally improved. Furthermore, leaves neem fibers contribute strongly in comfort thermal, but their use has a negative effect on durability. Nevertheless, adobes reinforced with neem fibers are suitable as building materials with substantial thermal comfort and environmental benefits.

In those cases where construction-generated soils with high water contents are used as filling or embankment materials, it is sometimes difficult to satisfy the specified compaction degrees. Recently, soil stabilization using a paper sludge ash-based stabilizer (PSAS) has been developed. Paper sludge (PS) ash is waste generated by the incineration of PS discharged from paper mills. It has been found that PS ash can absorb and retain excess water; and therefore, PS ash can simultaneously improve the stability of muds when it is mixed with them. However, the current mixture design approach for PSAS-treated soils is only applicable to muds with water contents exceeding the liquid limits and cannot be applied to construction-generated soils in which the coarse fraction is dominant. Therefore, this study evaluated the effects of a PSAS on the compaction and mechanical characteristics of coarse-grained soils to use them as materials for irrigation earth dams. A series of compaction tests were conducted on two types of soil samples treated with a PSAS to investigate its effects on the compaction characteristics. The compaction characteristics obtained from the tests were assessed considering the water absorption and retention performance of the PSAS. It was found that the modified optimum water content w*opt of the treated samples, which was evaluated using the amount of water unabsorbed and unretained by the PSAS, was almost equal to the wopt of the untreated samples. Consequently, a new mixture design approach was proposed based on the compaction characteristics. The calculated results successfully demonstrated that, if the compaction curve of an untreated sample and the water absorption and retention ratio, Wab, of the PSAS corresponding to a certain curing period are obtained, the range in the PSAS addition amount, APS1m3, required to attain the targeted compaction degree, (Dc)target, for the curing period can be estimated without conducting compaction tests on the treated samples. Finally, the strength characteristics of the treated samples prescribed by the proposed mixture design method were investigated by conducting CBR tests and CU ¯ TC tests. Based on the test results, discussions were made on the contribution of the proposed mixture design to the strength development of the treated samples and on the development mechanism.

This research investigates a microwave transduction-based humidity sensor that is a promising candidate for real-time clinical healthcare applications and green miniaturized wearable electronic devices. Optimization of sensing material, sensing platform, and device fabrication techniques produces a carbon dots (CDs)-decorated metal organic framework (MOF)-derived porous Co3O4 (CDs-Co3O4) microwave resonator-based sensor with excellent real-time humidity detection. Inspired by the water absorption component polyacrylamide in baby diapers, the acrylamide is adopted to synthesize CDs for microwave humidity sensor. Combining CDs with MOF-derived porous Co3O4 enhances humidity sensitivity under microwave excitation, with a frequency shift of 3.40 MHz/% RH and a loss variation of 0.15 dB/% RH between 5% and 99% RH. These values are 49.7% (for frequency shift) and 20.5% (for return loss) higher than Co3O4 sensor. Moreover, CDs-Co3O4 exhibits high selectivity towards water vapor against other volatile organic compounds, and the response or recovery time are both less than 5 s. Fabricated by an integrated passive device technology, the sensing platform is miniaturized at 0.98 × 0.80 × 0.22 mm3 with superb device stability and reliability. The CDs-Co3O4 sensor remarkably monitors respiratory patterns of breathing or apnea, as well as subtle changes in the humidity levels of an approaching finger. A charge transfer process and microwave interactions are the mechanisms for improved humidity sensitivity.

Construction sludge frequently has high alkalinity after its generation or during the intermediate treatment process. The aim of this study is to experimentally investigate the potential of combining accelerated carbonation and a paper sludge ash-based stabilizer (PSAS) to neutralize the alkalinity of construction sludge in a short period and to improve its strength for use as a recycled material. The experimental results indicate that the addition of a PSAS significantly granulated the alkaline sludge, and once granulated, the PSAS successfully accelerated the pH neutralization of the alkaline sludge. It was also found that the decrease in dry density ρd and the degree of saturation Sr of the PSAS-treated sludge was able to reduce the period required for the pH neutralization, tN. The decrease in ρd is thought to allow fresh CO2 gas to penetrate the specimen more easily. However, if Sr is below a certain limit, it does not strongly facilitate the reduction of tN. This implies that pH neutralization cannot be accelerated when the amount of water in the sludge is below a certain level. Moreover, it was found that mean particle diameter D50 also affected tN. The strength development of the PSAS-treated sludge was evaluated using a series of cone index tests. It was found that the strength of the alkaline sludge without the PSAS was significantly decreased by accelerated carbonation, but was significantly increased even after accelerated carbonation when the PSAS was present. Due to the porosities of the remaining PS ash particles, most of the contribution of the water absorption and retention performance of the PSAS to the strength development of the PSAS-treated sludge was secured after accelerated carbonation. In addition, the granulated particles of the PSAS-treated sludge retained their granular shape to some extent. Therefore, it is presumed that the friction and interlocking of the particles did not decrease significantly. It was also found that, after carbonation, the qc of the PSAS-treated sludge increased more rapidly than that of the alkaline sludge without the PSAS. A further detailed examination of the test results showed that under air-curing conditions, the qc of the treated sludge with accelerated carbonation increased relatively gradually compared to that of the treated sludge without accelerated carbonation.

Using microwave heating technology to assist concrete recycling have great potential for improve the quality of recycled concrete aggregate. Unfortunately, there are few studies explored on the properties of concrete incorporating microwave treated coarse aggregates. This study aims to investigate the performance of coarse aggregate after microwave treatment and to evaluate the properties of the resulting concrete incorporated microwave treatment aggregate. The water absorption and crushing value tests were carried out to study the effect of microwave heating treatment on the physical properties of coarse aggregates. Concrete incorporated aggregate with various microwave heating parameters was fabricated and tested. The results indicated that physical performance of microwave treated aggregate was within the range of specification requirement and water absorption and crushing value of coarse aggregate heated under low microwave power levels (2–3 kW) is very closed to the untreated samples, while coarse aggregates treated with high power levels showed a significant increase. It was also observed that concrete made out of low microwave power levels heated aggregates are able to achieve strength on par with natural coarse aggregate concrete. In addition, in case of similar strength, the elastic modulus of microwave treated aggregate concrete is similar to natural aggregate concrete. These results indicate that using low microwave power levels to assisted aggregates recycling can reduce the damage to coarse aggregates to some extent, which provide a further understanding for the application of microwave-assisted aggregates recycling.

In this present study, the demolition of building waste is used as an RCA in concrete. The various techniques like mechanical and chemical treatments are presented to recover the properties of RCA. Six dissimilar concrete mixtures were prepared using virgin coarse aggregate, RCA; aggregate obtained after treatment of Mechanical scrubbing (MS), Sulphuric acid (H2SO4) and Hydrochloric acid (HCl). The compressive strength of treated aggregate was enhanced by 7.78–25.79% than untreated recycled aggregate concrete. Split tensile strength has been enhanced by 5.22–18.80% higher than the untreated aggregate. The flexural strength of various treated RAC was improved by 4.91–25.24% at 28 days more than untreated recycled aggregate concrete. Alkalinity value of concrete is made with all types of coarse aggregates, the assessment of pH lies between 11.9 to 12.24 and it is pretty good. In drying test, the values are improved by 6.07–28.88% at 28 days than untreated coarse aggregates concrete. In water absorption test; the treated aggregate improved their results by 4.84–31.06% than untreated aggregate concrete. The investigation shows better results from various treated RCA in concrete. Especially, mechanical scrubbing (MS) treatment recovered higher than other techniques. But the results do not exceed the conventional concrete.

The hygroscopicity of expanded vermiculite is one of major influence factors for thermal insulating performance. To explore the water absorption properties of expanded vermiculite prepared via electrical heating method, heating temperature effect on the hygroscopicity of expanded vermiculite was investigated under various humidity circumstances. The influencing mechanisms were analyzed by means of Thermogravimetric Analysis-Differential Scanning Calorimeter technique (TG-DSC), Fourier-Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and the Brunauer–Emmett–Teller technique (BET) for the measurement of the specific surface area. The results of water absorption experiments indicated that the hygroscopicity of vermiculite showed an inversely proportional relationship to heating temperature and the water absorption content of EV-900 was only 6.206 mg/g with a dramatic decline of 91.5% in comparison with that of RV. This decline of water absorption capacity was mainly attributed to the decrease of interlamellar spacing and specific surface area. In addition, environment humidity had a significant effect on water absorption capacity and velocity. The water absorption content of EV-400 sample increased dramatically from 48.414 mg/g at the humidity of 55%–72.929 mg/g at the humidity of 95%, and the equilibrium time reduced from 3 h to 0.5 h. This study will provide a new perspective and theoretical guidance for the development of vermiculite based thermal insulating materials.