Reduction In Flexural Strength Research Articles

Experimental Studies of the Effect of SO2 on the Mechanical Properties of Selected Cladding Natural Stones

Natural stones are influenced by environmental conditions that might affect their performance and durability as building cladding elements. Among these environmental conditions, one that is not well explored is the study of the impact of SO2 deposition on the mechanical properties of ornamental stones. In this paper, the effect of a SO2-rich atmosphere (constant 10 ppm, with cyclic variations of temperature and relative humidity) on the physical-mechanical properties of some stones from Portugal (three granites and two limestones) is evaluated. Comparative studies on unaged and artificially SO2-aged samples were conducted. Samples were characterized by stereomicroscopy, scanning electron microscopy–X-ray energy dispersive spectroscopy (SEM-EDS), weight variation, and evaluation of elastic dynamic modulus through the fundamental resonance method and of flexural strength under concentrated load. Three granites—Amarelo de Vila Real, Cinzento de Alpalhão, and Cinzento de Pedras Salgadas—and two limestones—Moleanos and Semi-Rijo—from Portugal were chosen, as they are commonly used as cladding natural stones on façades. The obtained results showed that SO2 reacted with both silicate and carbonate stones; neoformed calcium sulfates were identified through SEM with different morphologies and in distinct levels. Its formation induced macro- and microstructural and mechanical modifications. Indeed, calcium sulfate crystallization critically affected mechanical performance through a reduction of elastic modulus and flexural strength in different degrees. Based on the flexural strength and dynamic modulus of elasticity variations, it is possible to recognize that only one granite, Cinzento de Alpalhão, presented lower failure risk in a cladding application. Thus, in urban SO2-rich environments, the effect of this pollutant on natural stone performance should be considered in the material selection stage, leading to improved cladding stone behavior and thus increasing stone service life.

Effects of tool coating and tool wear on the surface quality and flexural strength of slotted CFRP

Machining of carbon fibre reinforced polymer (CFRP) is abrasive and causes significant tool wear. The effect of tool wear on static flexural strength is investigated, using edge trimming with uncoated carbide and chemical vapour deposition (CVD) diamond coated burr style tools. Edge rounding (ER) criteria along with flank wear are used to observe tool degradation with ER shown to preferentially wear allowing the tool to become cyclically sharper and duller, corresponding to fluctuating dynamometer readings, a novelty for CFRP machining. Areal surface metrics degraded for an uncoated tool due to changes in cutting mechanism, whilst for up to 16.2 m of linear traverse, the coated tool showed limited changes. Tool wear, caused by edge trimming 7.2 m of CFRP, using an uncoated carbide tool, provided a flexural strength reduction of up to 10.5 %, directly linking tool wear to reduced mechanical strength.

Wear Properties and Post-Moisture Absorption Mechanical Behavior of Kenaf/Banana-Fiber-Reinforced Epoxy Composites

The contribution of natural lignocellulosic fibers to the reduction in wear damage in polymer resins is of interest, especially when two of these fibers can combine their respective effects. Wear properties of hybrid kenaf/banana epoxy composites have been investigated using three different total amount of fibers, 20, 30 and 40 wt.%, at loading forces up to 30 N and to sliding distances of up to 75 m. This demonstrated that the introduction of the highest level of fibers proved the most suitable for consistency of results and containment of wear with increasing load, as was also found from the morphological evaluation of wear degradation using scanning electron microscopy (SEM). Subsequently, tensile, flexural and impact properties of as-received and post-water-saturation hybrid composites were examined. The tests revealed a limited reduction in tensile and flexural strength, not exceeding 10% of the initial values, which were very high compared to similar materials, almost reaching 140 MPa for tensile strength and exceeding 170 MPa for flexural strength. In contrast, a higher standard deviation of values was found for impact strength, although the decrease in average values was only slightly above 10%. The results suggest the availability of these hybrids for wear-resisting applications in high-moisture environments, and the even more limited water absorption conferred by banana fibers added to kenaf ones.

Investigation of physico-mechanical, thermal properties and solar thermoregulation performance of shape-stable attapulgite based composite phase change material in foam concrete

Thermal energy storage (TES) by means of phase change materials (PCM) is of great concern to decrease heating and cooling loads. In building envelopes, one of the most efficient TES methods is integration of PCMs with construction materials for preventing temperature fluctuations by taking advantage of energy storage/release feature of PCMs. Aim of this research was to develop novel foam concretes containing shape-stable attapulgite (ATP) based composite PCM as TES material. Shape-stable ATP/Capric-Myristic acid eutectic mix composite (ATP/C-M) was incorporated into foam concrete at three different ratios (15, 30 and 45 wt%) and characterized. Impacts of ATP/C-M inclusion on physico-mechanic and TES characteristics of foam concretes including composite PCM (FCPCM) were worked systematically. DSC results showed that ATP/C-M composite melts at 22.12 °C with latent heat storage capacity of 74.97 J/g, whereas FCPCM-45 melts at 21.05 °C with latent heat storage ability of 10.98 J/g. Inclusion of ATP/C-M instead of silica sand decreased flow diameter of foam concretes. Compared to reference mixture FCPCM-0, compressive strengths of FCPCM-15, FCPCM-30 and FCPCM-45 samples were reduced in the range of 11–46% while reduction in flexural strength was found to be about 35–57% at 28th day. All FCPCM samples showed lower thermal conductivity values than the specified value and could be defined as better insulation materials. Solar thermoregulation performances of foam concretes containing ATP/C-M were comparatively tested in laboratory and also actual ambient conditions. Results showed that foam concretes with acceptable mechanical properties can be used for internal temperature controlling and energy saving in buildings.

Superdurable fiber-reinforced composite enabled by synergistic bridging effects of MXene and carbon nanotubes

The corrosion of fiber-reinforced polymer (FRP) composite has given rise to a tricky problem with implications in many fields including civil, aerospace, and environment. The degraded mechanical performance of FRP caused by corrosion usually results from surface and interface corrosion, which is especially problematic in the humid and alkali environment. Herein, basalt fiber reinforced polymer (BFRP) reinforced with 3D MXene Ti3C2Tx/carbon nanotubes (CNTs) nanofillers with long-term stability was fabricated and the reinforced mechanism was investigated experimentally. Results show that the synergistic effect of MXene/CNTs can obviously enhance the interfacial adhesion between adjacent fiber yarns and increase the tensile strength and flexural strength of BFRP composite by 53.5% and 43.2%, with pure BFRP as a comparison. The effectiveness of MXene/CNTs to act as corrosion inhibitor was evaluated by alkali immersion testing. After 120 days of immersion in alkali solution, bare BFRP had a significant increase in surface defeats and roughness, which resulted in remarkable reduction in flexural strength. In contrast, MXene/CNTs-BFRP composite exhibited negligible changes in both surface roughness and flexural strength. Therefore, the present work provides the new hybrid carbon nanofillers with a unique structure, which makes FRP capable enough to serve in more complex environment.

Effects of particle size optimization of quartz sand on rheology and ductility of engineered cementitious composites

In this study, the effect of particle size of quartz sand on the fresh and hardened properties of engineered cementitious composites (ECC) was investigated. For this purpose, three ECC mixtures that are identical except for the gradation of quartz sands used in their composition were designed. One of the mixtures includes a combination of quartz sands with amounts determined by the Andreasen and Andersen particle size optimization model while the remaining two have a finer and a coarser gradation. In the fresh state, mini slump, mini V-funnel and bleeding tests were applied, and rheological parameters were determined according to Bingham and modified Bingham models by using a rotational viscometer. In the hardened state, flexural strengths, mid-span deflections and numbers of microcracks formed under flexural loading were determined at 7 and 28 days. It was observed that the particle size optimization of the quartz sand can provide a balance between flow and bleeding characteristics of ECC mixtures. Although a reduction in flexural strength occurred at both ages in the optimized ECC mixture, the deflection capacity and the crack formation capacity under loading were significantly increased, reaching a deflection value of over 10 mm with at least 11 cracks formed during the test. As a result, it was revealed that particle size optimization can yield a mixture with the highest ductility without compromising the workability of ECC.

Two possible in vitro alternatives to evaluate the effect of gastric acid on resin-based composites.

BackgroundObjective: To compare two in-vitro protocols to study the effect of simulated gastric acid on the mechanical properties of resins based composites(RBCs). Material and MethodsThree RBC FILTEK Supreme XTE (FS), BRILLIANT EverGlow (BE), GrandioSo (GS) were used. They were randomly divided into a control group (CG) and two groups exposed to simulated gastric acid: a 6-month daily protocol (DG) and an accelerated 90-min protocol (AG). Vickers microhardness (VH) and flexural strength were evaluated at baseline and six months. Statistical analysis was performed using repeated measures ANOVA tests for VH and three-way for flexural strength data (α=0.05). ResultsDaily exposure in the CG and DG groups caused a reduction in VH values and flexural strength (p<0.05). The majority of values in the AG remained stable, after an exposure of 90 min; FS (p=0.118) and GS (p=0.729) in VH and FS (p=0.377), BE (p=0.692) and GS (p=0.672) in flexural strength. ConclusionsDaily exposure during 6 months caused significant changes in the VH values and flexural strength of the RBCs. The acid-accelerated protocol did not cause the same magnitude of change in VH values and flexural strength seen at six months of daily exposure. Key words:Gastric acid, hardness, composite resins, flexural strength, dental materials.

Effect of 6 Hour Fire on Flexural Strength of RC Beams made with 50% Coarse Aggregates from old concrete: Part 1: Normal mix

Shifting of people from villages/small cities to big cities poses a serious issue of accommodation and other associated infrastructure. For the solution of said issue, demolition of old structures to construct new high-rise buildings is opted. The demolishing waste is an additional problem for the project, particularly due to unavailability of the dumping space in many areas. A method of addressing the issue is by using it in new concrete. This research study presents an experimental investigation to check the effect of a 6-hour fire at 1000◦C on the bending resistance of reinforced concrete beams prepared by replacing 50% conventional coarse aggregate with coarse aggregate from demolished concrete. 24 RC beams of 0.9m × 0.15m × 0.15m size are cast using 1:2:4 mix and 0.54 water cement ratio. To reinforce the beams 2#4 bars in each tension and compression zones are used. Out of 24 beams, 12 are cast with all-natural coarse aggregates to compare the results. After 28-days standard curing, all beams are exposed to fire for 6 hours in purpose made oven. The beams are then left at room temperature for 24-hours followed by testing of all the beams in universal load testing machine with central point loading. Load and deflection are monitored at regular intervals. Comparison of the results with control specimen shows that the proposed beams observed 13.43% reduction in flexural strength which is quite smaller. The beams failed in shear which complies with the failure mode of normal concrete beams. Thus, the proposed material has good fire resistance when used in reinforced concrete beams.

Flexural strength of 3Y-TZP bioceramics obtained by direct write assembly as function of residual connected-porosity

The present work reports the effect of the extrusion nozzles' size and consequent residual porosity on the flexural strength of 3Y-TZP bioceramics fabricated by direct write assembly technology. A printable ink containing a volume fraction of 45% of 3Y-TZP (ZrO2 stabilized with 3mol% Y2O3) submicron powder, carboxymethyl cellulose and polyethyleneimine as additives was fine-tuned by rheological measurements. Different nozzle diameters (0.41mm, 0.33mm, and 0.25mm) were used to print 3D specimens with proper dimensions for structural and mechanical characterization after sintering, namely relative density, linear shrinkage, and three-point flexural strength. Bulk surface sample and exposed fractured surfaces after flexural strength tests were analyzed by X-ray diffraction, Rietveld refinement and scanning electronic microscopy. Strength reliability and failure probability of the three sample groups were analyzed by Weibull statistics. The sintered samples exhibited relative densities in the range of 78% (nozzle Ø 0.41=mm) and 82% (nozzle Ø 0.25=mm), i.e., a slight increase in the residual interfilamentous porosity is observed, as the extrusion tip diameter increases, while linear shrinkage is statistically similar (≈25%). Likewise, a progressive reduction of flexural strength and Weibull modulus as nozzle diameter increases was noticeable, being respectively σf=337,5±49MPa and m=6.6 for the smallest nozzle diameter (Ø=0.25mm) and σf=261.4±79MPa and m=3.2 for the biggest one (Ø=0.41mm). Unlike nozzle diameter, the material is constituted by 79-81wt% tetragonal t-ZrO2 and 19-21wt% cubic c-ZrO2 with equiaxed grain sizes between 0.3 and 0.6μm. X-ray diffraction analyses on the fracture surface of flexural test samples suggests that the toughening mechanism by tetragonal→ monoclinic phase transformation is the main responsible for the mechanical strength of this structural ceramic. Additionally, the reduction of flexural strength for samples printed with extrusion nozzle of 0.41mm could be explained by the surface roughness of the bending surfaces, as well as the lower effective resistance to crack-propagation arising from the higher size of residual pores on the fracture surface.

Study on mechanical properties of concrete inclusion of high-volume coal bottom ash with the addition of fly ash

Coal bottom ash (CBA) has been widely utilized in concrete production as a partial replacement for aggregate. Still, the massive amount of CBA generated every day ends up dumped at a landfill without economic value. Therefore, the aim of the study identified the influence of CBA as a coarse and fine aggregate replacement, in addition of fly ash (FA) as a partial cement substitution in concrete made. The experimental tests were carried out on the fresh and hardened state of concrete to evaluate the workability test, compression test, flexural test, and modulus of elasticity test. CBA was replaced in concrete by four different combination arrangements between half (50%) and full (100%) coarse and fine aggregate using the volume replacement method. Then, 20% of FA was substituted to the mass of cement as an additive cementitious material to enhance the pozzolanic reaction. The results revealed that a high amount of CBA in concrete contributed to the low workability of fresh concrete. The concrete made by 100% CBA as coarse and fine aggregate replacement produced better compressive strength than the control concrete. Besides, all replacement levels of CBA in concrete had a modulus of elasticity in the range of 5.07 to 5.67 GPa, which is acceptable for its compression strength of 30 to 35 MPa at 28 days. Besides, CBA concrete recorded a significant reduction in flexural strength with the increment level of percentage CBA in concrete mix ingredients. Therefore, the evaluation of the mechanical properties of concrete containing large volume CBA with the addition of FA shows good performance and has the potential to be utilized in concrete manufacturing.

Mechanical and Thermogravimetric Properties of PP Based Thermoplastic Composites Reinforced with Cotton and Polyester Waste under Dry and Wet Conditions

ABSTRACT The textile waste-based composites are environmentally friendly and economical. This study reports polypropylene composites reinforced with cotton fibers extracted from waste textiles and polyester fibers generated in the industry. The composites reinforced with 40 wt% of cotton fibers exhibited a reduction in tensile and flexural strength by ~50 and ~20%, respectively and compared to neat polypropylene. However, the Young’s and flexural modulus increases by ~36 and ~4%, respectively, compared to neat polypropylene. The izod impact strength of composite reinforced with 40 wt% of cotton increases by ~58% than neat polypropylene. Similarly, the composites reinforced with 40 wt% of polyester fibers exhibited a reduction in tensile, flexural, and impact strength by ~107, ~60, and ~23%, respectively, compared to neat polypropylene. The Young’s and flexural modulus also decreases by ~38 and ~78%, respectively, compared to neat polypropylene. The equilibrium water content of the composite was found to increase with cotton fiber loading.

Research on Compressive and Flexural Properties of Coal Gangue-Slag Geopolymer under Wetting-Drying Cycles and Analysis of Micro-Mechanism.

Coal gangue-slag geopolymer is a kind of environment-friendly material with excellent engineering performance and is formed from coal gangue and slag after excitation by an alkaline activator. In this study, three kinds of coal gangue-slag geopolymer were activated by different activators, and the compressive and flexural strengths of water and sulphate solutions in the wetting-drying (W-D) cycles were compared. The microscopic mechanism was analyzed by the XRD, the FTIR and the SEM. The following conclusions are drawn: The influence of W-D cycles on flexural strength was greater than compressive strength. The water migration and the recombination of geopolymers lead to the change of colour, as well as the reduction of flexural strength and compressive strength of geopolymers. The SH geopolymer had excellent anti-erosion ability in terms of flexural strength, and the reason for this was the recombination and polymerization reaction of geopolymer being weaker than the SS and the SSG. The corrosion resistance of the SS was reflected in the compressive strength, because its geopolymerization reaction was fierce, which produced more Na-rich C–N–A–S–H, N–A–S–H and C–A–S–H gels. Therefore, the compressive strength could still reach more than 39 MPa after 150 cycles. Sulfate solution could effectively control the reduction of compressive strength of the SH and the SS geopolymers during W-D cycles. The SSG had the worst corrosion resistance.

Influence of shear on plastic bending strength of I cross-sections steel beams

In general, steel beams are stressed by bending and shear. Due to the loading a normal stresses σ and shear stresses τ arise in individual cross-sections of steel beams. But they are usually stressed mainly by bending. This follows both from several theoretical analyzes and especially from the corresponding experiments. Therefore, current standards for the design of steel structures allow the impact of shear to be neglected to a certain level of shear stress of the most stressed - decisive cross-sections of beams (EN 1993-1-1, respectively CSN EN 1993-1-1 and others). However, in the case of shorter beams, especially in places of support and in places of application of concentrated forces, the shear effects of the load can also be significant. In the case of more significant shear effects of the load, the plastic flexural strength of the decisive cross-sections and also the overall load-bearing capacity of the steel beams must be adequately reduced. However, the degree of flexural strength reduction with a significant effect of shear in the case of I cross-sections is still unambiguous. It is therefore important to experimentally investigate steel beams in the area of significant shear effects. The presented article contains selected results of experimental investigation of the significant effect of shear on the flexural strength of steel beams I cross-sections.

Acute and severe trabecular bone loss in a rat model of critical illness myopathy.

Prolonged mechanical ventilation for critically ill patients with respiratory distress can result in severe muscle wasting with preferential loss of myosin. Systemic inflammation triggered by lung mechanical injury likely contributes to this myopathy, although the exact mechanisms are unknown. In this study, we hypothesized that muscle wasting following mechanical ventilation is accompanied by bone loss. The objective was to determine the rate, nature, and extent of bone loss in the femora of rats ventilated up to 10 days and to relate the bone changes to muscle deterioration. We have developed a rat model of ventilator-induced muscle wasting and established its feasibility and clinical validity. This model involves pharmacologic paralysis, parenteral nutrition, and continuous mechanical ventilation. We assessed the hindlimb muscle and bone of rats ventilated for 0, 2, 5, 8, and 10 days. Routine histology, microCT, and biomechanical evaluations were performed. Hindlimb muscles developed changes consistent with myopathy, whereas the femurs demonstrated a progressive decline in trabecular bone volume, mineral density, and microarchitecture beginning Day 8 of mechanical ventilation. Biomechanical testing showed a reduction in flexural strength and stiffness on Day 10. The bone changes correlated with the loss of muscle mass and myosin. These results demonstrate that mechanical ventilation leads to progressive trabecular bone loss parallel to muscle deterioration. The results of our study suggest that mechanically ventilated patients may be at risk of compromised bone integrity and muscle weakness, predisposing to post-ventilator falls and fractures, thereby warranting interventions to prevent progressive bone and muscle decline.

Influences of shrinkage reducing admixture on the mechanical properties, drying shrinkage, water absorption and porosity of Portland cement mortar

Drying shrinkage is the main cause of early age cracking of concrete and mortar. A wide range of research has been conducted to reduce the drying shrinkage, including using fibres or chemical admixtures. This paper investigated the effect of shrinkage reducing admixture on the flexural strength, compressive strength, drying shrinkage, water absorption and porosity of mortar. The mix compositions were ordinary Portland cement (OPC) : sand : liquid = 1: 1: 0.38 in which liquid consisted of water and shrinkage reducing admixture (SRA). SRA was used at the proportions of 2%, 4%, and 7% by weight of cement. The test results show that SRA reduces the flexural and compressive strengths of mortar. The reduction in flexural strength and compressive strength at 28 days is 14% and 25%, respectively at 7% SRA dosage. In addition, SRA significantly reduces the drying shrinkage and water absorption of mortar. At 7% SRA dosage, the drying shrinkage at 53 days is reduced by 60% while the water absorption rate at 24 hours is reduced by 54%. However, SRA has a minor effect on the pore size distribution, effective porosity, and cumulative intrusion volume of mortar.

Ferro-geopolymer composites for roofing – A sustainable approach for infrastructures

Ferro-geopolymer is an upcoming building material that replaces the need for cement in construction practices and thereby reducing its carbon footprint. It is a composite consisting of geopolymer mortar matrix and wire meshes as reinforcement. The present study pioneers in the research of a prototype trapezoidal ferro-geopolymer roofing element under flexure. A total of nine specimens were cast, steam cured and subjected to third point loading. Three different spans of 2.5 m, 3.0 m and 3.4 m, and three different mesh types, (i) square welded mesh, (ii) square woven wire mesh, and (iii) hexagonal wire mesh, were the parameters considered for the study. Specimens reinforced with square welded wire mesh exhibited higher flexural strength compared with others, consequent to the additional strength imparted through the rigidity of welded connections. Maximum reduction in flexural strength of 20% and 32%, for specimens reinforced with square woven wire mesh and combination of hexagonal and square welded mesh, with respect to square welded wire mesh was observed for 3.0 m span beam elements. In addition, two analytical methods have been proposed to determine the ultimate flexural strength of ferro-geopolymer specimen and both methods were found to be in good agreement with the experimental results. The coefficient of variation of the predicted value of ultimate strength from the experimental value was obtained to be 9% for Method-I and 6% for Method-II.

Flexural Behaviour of Hybrid Concrete Beam-Column Connections Under Static and Repeated Loads

The present study includes an experimental investigations for the behavior and the load carrying capacity of hybrid beam-column connections subjected to static and repeated loading condition. The goals were to evaluate the effect of using slurry infiltrated fiber concrete (SIFCON). Experimental program consists of testing six beam-column connections, two of them casted with normal concrete and the other using SIFCON in crtical section in addation to normal concrete. Also, the program testing three of connection subjected to static load and the similar other subjected to repeated loads. Results show an improve in flexural behavior for specimens with SIFCON as compared with normal concrete under static and condition, on the other hand, the reduction in flexural strength when was exposed to repeated loads in comparison with that under static loads reach 2.6% at hybrid connection. While, the reduction was increased to 5.1% for the specimen without SIFCON.

Evaluating the synergic effect of waste rubber powder and recycled concrete aggregate on mechanical properties and durability of concrete

The use of waste materials in the concrete mixture can help human beings to preserve the environment and achieve environmentally-friendly concrete. In this study, the influences of simultaneous replacements of cement by waste rubber powder (WRP) and coarse aggregate by recycled concrete aggregate (RCA) on the mechanical properties and durability of concrete were investigated experimentally. To do so, concrete specimens containing the WRP with the replacement ratios of 0 %, 2.5 %, and 5 % by weight of cement, and the RCA with the replacement levels of 0 %, 25 %, and 50 % of coarse aggregate were prepared. Moreover, different water to binder ratios and binder content were used. Mechanical properties of the concrete specimens consisting of compressive, flexural, and tensile strengths and the durability test of rapid chloride migration test (RCMT) were carried out at different ages. It was observed that the mechanical properties of concrete decrease by raising the proportions of recycled materials in all replacement ratios. Because of the negative effects of the WRP and RCA on, respectively, the cement matrix and the interfacial transition zone, the reduction of the mechanical properties are higher for the concrete specimens with both recycled materials. In the case of durability, the migration rate of chloride ions in concrete reduces by increasing the WRP rates due to the blockage of micro-pores connections. However, adding the RCA has a negative effect on the durability performance of concrete. Finally, four equations were proposed and evaluated for the compressive, tensile, flexural strength reduction and durability factors of concrete containing the WRP and RCA using the genetic programming.

INFLUENCE OF WOOD SAW DUST AND WASTE GLASS ADMIXTURE ON SELECTED PROPERTIES OF FIRED CLAY BRICKS FOR MASONRY

This study investigated the effect of mahogany wood sawdust (WSD) and waste glass (WG) addition on the properties and cost of producing fired clay bricks for construction of houses. Materials used were clay, WSD and WG. Brick samples were produced in batches and labeled as samples A (with no additives), B, C, D, E, F, G and H. Each sample of B, C, D, E, F, G and H contained 5% fixed amount of WSD, and 10, 15, 20, 25, 30, 35 and 40% of WG respectively. Brick samples produced were tested for apparent porosity, bulk density, compressive and flexural strengths, thermal conductivity and wear. Results obtained showed that as waste glass content increased in the samples, bulk density and compressive strength increased due to enhancement of densification and compaction within the samples. Thermal conductivity also increased as waste glass increased due to reduction in porosity and reduced inter-particle distance. The value of flexural strength increased with WG content but at 35% and 40%, the value reduced. This is as a result of an increase in brittleness as waste glass content increased which increased stress concentration in the samples, hence leading to a reduction in flexural strength. Also, it was observed that the increase in the content of the waste glass led to a reduction in the value of apparent porosity and wear depth due to improved cohesion between particles in the bricks. Comparing results obtained with existing standards and considering the cost of production, 5% WSD and 25% WG addition, with apparent porosity of 26.3%, compressive strength of 17.5 MPa, thermal conductivity of 0.32 W/mk and wear depth of 1.72 mm is recommended for construction purposes.

Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.