Workability Tests Research Articles

Real-time data sensing and digital twin model development for pavement material mixing: enhancing workability and optimisation

ABSTRACT An essential aspect of pavement construction sustainability is its low-energy consumption and emissions. The study of pavement materials workability tests holds significant importance in terms of achieving well-mixed conditions with low-energy consumption. The complex components of the material and the uncertain kinematic behaviours of aggregates during mixing make this process challenging. And, few studies of the signal response of pavement materials have been found in the field of civil engineering. For this purpose, an accurate evaluation and monitoring approach for mixing are needed. In this paper, a wireless real-time sensing method is used to monitor the dynamic behaviour of aggregates during mixing. A 3D digital twin model, combining data-sensing techniques and numerical simulation, has been proposed for rapid identification of the mixing material. This model has been validated via a data-fusion algorithm. The application of this model makes a contribution to the data-intensive analysing jobs and decision-making tasks in pavement construction engineering.

Importance of pumice amount in the design of self-compacting lightweight concrete

Although concrete has high compressive strength values, it has a heavy unit volume and low tensile strength. In this study, the normal-weight aggregate, which takes up the most space in concrete by volume and mass, was partially replaced with pumice aggregate, and macro steel fiber (30 mm) was also added to the mixtures. This experimental work aims to investigate the effect of pumice aggregate amount on the fresh and hardened properties, as well as the flexural performance of the self-compacting lightweight concrete (SCLC). The replacement proportions of pumice aggregate with crushed sand were arranged as 45%, 50%, and 55% of the entire aggregate by weight. Three mixtures, each with 1% macro steel fiber reinforcement and without fiber, were prepared for each mixture scenario. The mix design of these six mixtures was arranged to achieve the self-compacting ability and the workability tests recommended by EFNARC (slump-flow, T50, J-ring) were taken into account. To investigate the mechanical properties (compressive, splitting tensile, and flexural strengths) and flexural toughness of the samples, the specimens were cured in water at 23±2 °C for 28 days. As a result, the unit volume weights of the specimens produced from pumice-substituted mixtures decreased with the increase in the pumice dosage, while the compressive, splitting tensile, and flexural strengths decreased. However, it has been determined that all SCLC mixtures including pumice aggregate provided workability properties in general and had enough compressive strength to be used in the production of structural bearing elements, regardless of fiber content. As a result, the optimum pumice aggregate replacement percentage with crushed sand was found to be 45% and the best flexural performance values of the specimens having macro steel fiber were observed in the ones having 45% pumice aggregate substitution.

Experimental Study to Investigate the Performance-Related Properties of Modified Asphalt Concrete Using Nanomaterials Al2O3, SiO2, and TiO2.

The dual nature of asphalt binder necessitates improvements to mitigate rutting and fatigue since it performs as an elastic material under the regime of rapid loading or cold temperatures and as a viscous fluid at elevated temperatures. The present investigation assesses the effectiveness of Nano Alumina (NA), Nano Silica (NS), and Nano Titanium Dioxide (NT) at weight percentages of 0, 2, 4, 6, and 8% in asphalt cement to enhance both asphalt binder and mixture performance. Binder evaluations include tests for consistency, thermal susceptibility, aging, and workability, while mixture assessments focus on Marshall properties, moisture susceptibility, resilient modulus, permanent deformation, and fatigue characteristics. NS notably improves binder viscosity by about 138% and reduces penetration by approximately 40.8% at 8% nanomaterial (NM) content, significantly boosting hardness and consistency. NS also enhances Marshall stability and decreases air voids, increasing the mix's durability. For moisture resistance, NS at 8% NM content elevates the Tensile Strength Ratio (TSR) to 91.0%, substantially surpassing the 80% standard. Similarly, NA and NT also show improved TSR values at 8% NM content, with 88.0% and 84.1%, respectively. Additionally, NS, NA, and NT reduce permanent deformation by 82%, 69%, and 64% at 10,000 cycles at 8% NM content, illustrating their effectiveness in mitigating pavement distress. Notably, while higher NM content generally results in better performance across most tests, the optimal NM content for fatigue resistance is 4% for NS and 6% for both NA and NT, reflecting their peak performance against various types of pavement distresses. These results highlight the significant advantages of nanoparticles in improving asphalt's mechanical properties, workability, stability, and durability. The study recommends further field validation to confirm these laboratory findings and ensure that enhancements translate into tangible improvements in real-world pavement performance and longevity.

Influence of Recycled Coarse Aggregate and Steel Fiber on the Workability and Strength of Self-Compacting Concrete

Abstract Waste materials pose a significant threat to both the environment and human health. On a global scale, the quantity of recyclable material is steadily growing, and its proper disposal is a significant focus of modern study. Concrete debris is a recyclable material that poses challenges for reutilization. Concrete waste refers to the fragments or remains of ready-mix concrete plants and the debris from destroyed structures, including historic buildings and those affected by earthquakes. The objective of this study is to reuse and utilize coarse aggregate formerly used in concrete constructions to create self-compacting concrete (SCC). The purpose is to assess the performance of this recycled aggregate in both its fresh and hardened states. Natural coarse aggregate (NCA) was switched out for recycled coarse aggregate (RCA) at 0, 50, and 100% volume ratios. In contrast, concrete was mixed with steel fibers (SF) at volume percentages of 0 and 0.44. Workability tests, including V-funnel, slump flow, and L-box tests, were conducted to assess the consistency of the mixes in their fresh condition. Additionally, the tensile and compressive strength of the concrete specimens were measured to evaluate their strength in the hardened state. Overall, the experimental findings showed that the fresh qualities of almost all SCC mixes fell within the required range, as outlined in the EFNARC standards. While the steel fiber harmed the fresh characteristics, it resulted in a proportionate enhancement in tensile strength. The findings indicated that including recycled aggregates into the concrete mixture enhanced its strength. The results showed that adding (0.44%) of steel fibers to concrete reduced the decline in compressive strength when the coarse aggregate was replaced entirely with recycled aggregate. In contrast, an equivalent proportion of fibers resulted in a significant improvement in tensile strength, rising from 26% to 54%, when using recycled coarse aggregate as the replacement of natural coarse aggregate. Thus, it can be concluded that using recycled aggregates and steel fibers in concrete production results in a higher quality product than regular concrete. Removing concrete waste has other benefits, such as enhanced financial return and preservation of the environment.

Spent coffee grounds enhanced compressive strength of cement mortar: an optimization study

This paper presents an optimization study of spent coffee grounds (SCG) as cement mortar additives to enhance mortar strength. In recent years, sustainable materials have begun finding their way into cement mortar, with SCG being one. There is limited optimization study on the SCG addition in mortars, hence this study was performed to optimize the curing time and SCG addition in cement mortar to achieve the highest compressive strength through response surface methodology. Scanning Electron Microscopy (SEM) characterization was carried out on the SCG particles to identify their physical properties. An Energy Dispersive X-ray (EDX) analysis was carried out to identify its chemical properties. Simultaneously, a workability test, the flow table test, is conducted to study the effect of SCG on the flowability of the cement mortar mixes. The synergistic effect between SCG content in cement mortar mixes and the curing period was statistically studied and analyzed. Both parameters were then optimized to obtain the best performance mix of SCG in cement mortar. It was found that 1.1% SCG and a curing day of 68 days produced the highest compressive strength (33.4MPa) of cement mortar. The Response Surface Methodology (RSM)-optimized cement mortar mix presented at least a 12.62% improvement in compressive strength from control cement mortar without SCG additives (28.77MPa). Experimental validation of the optimum condition showed a good agreement with a deviation of 3.12% in three replicates, thus indicating that the optimum model in this work can be used to model the compressive strength of the SCG-cement mortar mixture.

Kaolinite plastic binder in mortars: Rheological and mechanical properties

Portland cement and hydrated lime-based mortars are widely used in civil construction for covering and laying walls, sealing or structural restoration. However, the binders used in the production of mortar are produced in a way that is harmful to the environment, highlighting the need for alternative binders. In this work, the use of kaolinite plastic binder in mortars was evaluated, replacing hydrated lime with the material at levels of 0%, 50% and 100%. The importance of this study is to evaluate the feasibility of using an alternative binder in Portland cement and hydrated lime-based mortars. Fresh state properties were evaluated, such as consistency, squeeze flow and density in the fresh state; in addition to properties in the hardened state, such as compressive strength, water absorption, x-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization results of kaolinite plastic binder (D10 = 0.00009 mm and D60 = 0.0004 mm) show that the material has a particle size closer to hydrated lime (D10 = 0.00001 mm and D60 = 0.0004 mm), than Portland cement and quartz sand, evidenced by parameters D10 and D60. Additionally, the kaolinite plastic binder presents moderate pozzolanicity, indicating the feasibility of being used in this type of application. The workability tests show that kaolinite plastic binder has the potential to improve the workability of the mortar. In dynamic tests (consistency) it was observed that the 100% kaolinite plastic binder composition is viable as it promotes an increase in spread from 253 to 265 mm. In static tests (squeeze flow) the composition with 50% kaolinite plastic binder showed the best spreading results, with values of 10.7 mm, while the compositions containing 0% and 100% showed spreading of 8.97 and 7.40 mm, respectively. This demonstrates the potential for using kaolinite plastic binder in mortars. The hardened state results, such as compressive strength and water absorption, were also satisfactory. Although the compressive strength values showed a reduction with the use of kaolinite plastic binder, the values reached 7.5 MPa after 28 days, which is compatible with the proposed application. Finally, it was observed from the results of XRD and SEM that the kaolinite plastic binder shows adhesion with the hydration products of the Portland cement in the mortar, promoting a reduction in ettringite and portlandite due to its moderate pozzolanicity. Based on these results, it is possible to conclude that kaolinite plastic binder is a viable substitute for hydrated lime in mortars.

Studying the usability of recycled aggregate to produce new concrete

One of the most significant environmental issues worldwide is garbage, particularly waste from construction materials, which is generated in substantial numbers. However, in the building industry, the significant extraction of natural resources such as cement, natural sand, and natural gravel poses a critical environmental challenge, depleting these resources at an alarming rate. There are some solutions that developed countries are resorting to, namely the division of construction waste into groups, where it is reused under the name of recycling construction waste to produce new, environmentally friendly building materials. The aim of this research includes a laboratory process study as it includes the use of the following ratios: 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100%, under the process of replacing coarse plain aggregates including coarse recycled aggregates and studying the most important mechanical properties of concrete. This research was carried out using fresh concrete properties such as workability tests and hardened concrete properties such as compressive strength, splitting, and flexural tensile strength examined at the durations of 7, 14, and 28 days. The research includes the investigation of the three main properties of concrete. After conducting the tests, the results have shown that the main property of recycled concrete is lower strength than that of conventional concrete, but it can be said that it is within the limits that can be used for construction. The results also showed that compared to normal aggregates, development in the recycled aggregate percentage rates reduces the operational workability of concrete. The research proved that the maximum decrease in compressive, flexural, and tensile strength, density and the slump were 19.4, 18.3, 19.6, 19.5, and 25.0% respectively compared to the control concrete samples.

The Role of Superplasticizers on the Workability Consistency of ECC Mortar Fresh Mortar Due to an Increase in the Percentage of Palm Shell Ash

Engineered cementitious composites (ECCs) are composites that have better attraction properties and behavior than concrete. ECCs are usually formed from cement, water, silica sand, cementitious materials, fibers, and other additives with a certain proportion. In this study, there are three types of ECC mortars (types AME, EM, and TEM) where these types are differentiated by the amount of cement used, the quantity of water, and the number of sand used. Each type uses ashes of palm shells with the same proportions of 0%, 5%, 10%, and 15% of the weight of cement. According to trial and error during the workability test, the number of superplasticizers used also increased according to the increase in the percentage of ash in the palm shell, where the variation of superplasticizers achieved was 0.70%, 1.59%, 2.49%, and 3.40% of the weight of cement. Based on the results of the slumpflow test, the average diameter of the ECC freshly mixed mortar was between 88 cm and 106.5 cm, and the T500 slump flow was between 0.28 seconds and 1.39 seconds. The test results show a fairly good workability consistency of all ECC fresh mortars, although there has been an increase in the percentage of palm shell ash used. Superplasticizer turns out to be very important in maintaining consistent workability of fresh ECC mortar mix.

Effects of coal fly ash as partial replacement for cement towards concrete properties

Abstract The use of industrial waste, particularly fly ash (FA), as a substitute for ordinary portland cement (OPC) has gained attention due to global trends promoting the recovery and utilization of waste materials in construction. Previous research has demonstrated that fly ash has the potential to replace cement without compromising the strength of concrete, driving further exploration and validation of this concept. In a study investigating the effects of fly ash replacement in concrete, different percentages of fly ash were used to replace OPC in C25 grade concrete. Various tests were conducted, including X-ray fluorescent (XRF) analysis, sieve analysis, workability test, compression test, and water absorption test, to assess the characteristics, properties of the materials, fresh and hardened concrete. The results indicated that the replacement of FA in cement showed significant effects, with the strength at 12.5 % and 15 % replacements reaching the target strength of pure concrete at both 7 days and 28 days. These findings suggest that fly ash, at these replacement levels, exhibits desirable strength comparable to OPC, making it a viable alternative.

Printability region for 3D-printable engineered cementitious composites (3DP-ECC)

The integration of reinforcement in 3D concrete printing (3DCP) presents a major challenge in current 3DCP industry. Engineered cementitious composites (ECC) with self-reinforcing characteristic provides a promising solution. However, the conflicting requirements between extrudability and buildability are amplified for 3D-printable ECC (3DP-ECC) due to the existence of a large-amount of fibers. This study investigates the printability region for 3DP-ECC based on standardized field-friendly workability test. The effects of superplasticizer (SP) dosage, hydroxypropyl methylcellulose (HPMC) dosage and fiber content on the workability and printability of 3DP-ECC at varying resting times were explored. The results of grey relational analysis (GRA) show that the workability can be regulated by SP dosage, HPMC dosage, fiber content and resting time. The workability test results in conjunction with the printability evaluation results were used to define the printable region. The suitable ranges of workability parameters including spread diameter, slump, and penetration depth for 3DP-ECC are 130–142.5 mm, 1–31 mm, and 7.5–22 mm, respectively. In addition, the hardened mechanical properties of 3DP-ECC with satisfactory printability were examined by tensile and compressive performance. This study proposes a simple but effective method for predicting the printability of 3DP-ECC and the findings provide guidance for researchers and engineers to easily develop printable ECC.

Workability Tests and Rheological Properties of Manufactured Sand

Workability Tests and Rheological Properties of Manufactured Sand

PENGGUNAAN BAHAN ADITIF MASTER GLENIUM ACE 8595 UNTUK MEMINIMALISIR POROSITAS PADA BETON

<p><em>Concrete has now become the most essential material in modern construction. The strength and durability of concrete are vital factors that influence the strength and stability of buildings and infrastructure. Porosity refers to the degree to which concrete has voids or voids within its structure. Concrete porosity has a significant impact on concrete compressive strength. The higher the level of porosity, the lower the compressive strength of the concrete. In this research, we conducted a concrete formulation experiment by adding a type F additive to MasterGlenium Ace 8595. This research investigates the effect of adding the additive Master Glenium Ace 8595 on changes in concrete porosity and increasing concrete compressive strength. The results of the research show that from the aggregate suitability testing, it was stated that all the aggregates tested were suitable for use as a building material for concrete, workability testing obtained results with dilute criteria, porosity testing obtained an average porosity of 8.05%, and compressive strength testing obtained an average compressive strength value. -an average of 23.56 MPa indicates an increase of 8.69% of the planned concrete quality. This research concludes that concrete porosity is one of the factors that must be considered to increase the compressive strength of concrete because it significantly influences its density and compressive strength. Keeping the porosity at a low level and the compressive strength of the concrete at a high level can ensure that the concrete structure has good resistance to loads and the environment and reduces the risk of damage and maintenance.</em></p>

An experimental study on high strength self-compacting concrete inclusion of zeolite and silica fume as a potential alternative sustainable cementitious materials

One of the major sources of carbon dioxide and other greenhouse gases around the world is the cement industry. They make up 6–8 % of global warming. Therefore, by conducting this experiment, we may examine the possibility of replacing cement with different cementitious materials which include zeolite,silica fume and fly ash. These mineral additives will lessen the need for cement while enhancing the properties of the concrete that has just been hardened and also in fresh state. The objective of this experiment is to explore the impact of zeolite and silica fume on the physical and durability qualitiesof high strength, self-compacting concrete utilising nano silica that has been optimised. In the course of this study, various concrete mixtures were cast with zeolite and silica fume substituted for cement in varying amounts, and there was also a control mix for reference. These additives arereplacedcement in multiples of 5 up to 20 %. The preferred dosage as 2 % Nano silica is substituted as a regular mineral additive in all mixtures. Workability tests on the fresh qualities of concrete mixtures are conducted and the EFNARC stipulations are met by these experimental findings. All the concrete mixes' parameters, including strengths like splitting tensile and compressive were identified. Tests such as the Rapid chloride permeability test, the abrasion test, water absorption and desorption test were used to evaluate the concrete's durability.

Experimenting with the Utilization of Recron3S Fiber and Steel Slag in Fresh Concrete for Analysis

Abstract: Concrete is well-known for being the most frequently utilized construction material due to its affordability, longevity, and adaptability. However, traditional concrete production requires a large amount of cement and aggregate, raising concerns about its environmental impact and depletion of natural resources. In order to address these issues and promote sustainability, we have been exploring alternative materials like Recron3s polyester fiber and steel slag. Recron3s fiber can enhance the flexibility of concrete, making it a valuable addition. On the other hand, the steel industry generates a byproduct known as steel slag, which presents environmental challenges and disposal issues. Nonetheless, when incorporated into concrete, steel slag can improve the mechanical and physical properties of the material, increasing its durability. Our research focuses on replacing OPC 53 grade cement and natural aggregate with Recron3s fiber and steel slag aggregate, respectively. Different percentages of steel slag aggregate (0%, 20%, 25%, 30%) and Recron3s fiber (0%, 1.25%) were used as substitutes for traditional materials in M30 grade concrete with a water-cement ratio of 0.44. We created concrete mixes by partially replacing OPC 53 with Recron3s fiber and substituting natural aggregate with steel slag aggregate to evaluate the performance of eco-friendly concrete. We then evaluated the performance of these mixes through workability tests such as slump cone, vee-bee consistometer, and compaction factor test. Overall, incorporating Recron3s fiber and steel slag aggregate into concrete has yielded positive results in enhancing mechanical properties and reducing environmental impact.

High-strength self-compacting concrete produced with recycled clay brick powders: Rheological, mechanical and microstructural properties

High-strength self-compacting concrete (HSSCC), which has superior workability and filling ability compared to conventional concrete, is increasingly used in modern densely reinforced structures in the construction industry. However, HSSCC is more costly to produce than conventional concrete and can result in higher carbon emissions due to higher cement usage. On 6 February 2023, the devastating Kahramanmaraş earthquakes in Türkiye created a serious environmental problem. In this context, recycling and utilizing construction demolition waste (CDW), which creates a serious environmental problem after devastating earthquakes and urban transformations, can contribute to the economy of countries and environmental waste problems. In this study, to produce HSSCC more economically, sustainably, and environmentally, HSSCC series were produced using fly ash (FA) and recycled clay brick powders (RCBP) obtained from CDWs in certain proportions by weight instead of cement. For this purpose, seven different series of HSSCC were produced. FA and RCBP were used separately in the mixtures at 0% (control), 10%, 15%, and 20% by weight instead of cement. The fresh HSSCC series were then subjected to workability tests and cured for 28, 56, and 90 days. At the end of the curing period, physical and mechanical property tests and internal structure analyses by scanning electron microscopy (SEM) were performed on the HSSCC series. In addition, sensitivity analysis was performed using multiple linear model analysis to determine which parameters affect which properties in HSSCC designs. Although the highest workability loss in fresh HSSCCs was in the blend series where 20% RCBP was used, all of the blends provided fresh SCC properties by the standards. In general, the increase in FA and RCBP used in the HSSCC series decreased the 28-day compressive strengths (except RCBP10), while the strength losses gradually decreased as the curing age increased and at the end of 90 days; the compressive strengths of FA10 (71.9 MPa with 1.6% increase), RCBP10 (74.8 MPa with 5.6% increase) and RCBP15 (71.5 MPa with 1% increase) series were obtained above the control series (70.8 MPa). SEM analyses performed at the end of the study showed that HSSCC specimens with 10% RCBP replacement contained more intense hydration products and fewer pores than the other series.

EXPERIMENTAL INVESTIGATION ON HIGH STRENGTH CONCRETE USING PARTIAL REPLACEMENT OF RECYCLING COARSE AGGREGATE

The primary material used in construction is concrete. Cement, fine aggregates, coarse aggregates, and water make up concrete. However, the quick exhaustion of those resources and, consequently, their rising cost are becoming attention-seeking issues. As a result, the construction industries are facing difficulties related to the simple availability of those resources. This is why a number of solutions, such as the recycling and reuse of building waste, are being used to address the issue. In this area, our initiative seeks to use concrete that has been removed. In this project, we used M40 grade concrete to replace coarse aggregates with destroyed concrete in the following ranges: 0%, 20%, 30%, 50%, The prepared concrete mix is evaluated and compared to standard concrete in terms of workability tests, compressive strength, etc. The test will be run at 7, 14, and 28 days in order to evaluate the strength characteristics.

Research on Performance Improvement of Emulsified Asphalt Mixture Based on Innovative Forming Process.

Bulk density and porosity have great influence on the technical performance of an emulsified asphalt mixture, so in order to enhance the strength of the asphalt mixture, bulk density should be improved and porosity should be reduced. Considering the forming process of the emulsified asphalt mixture, the decrease in porosity can ensure the state of the mixture. In order to reduce the porosity of the emulsified asphalt mixture, an innovative forming process is proposed to improve the performance of the emulsified asphalt mixture, and its strength formation mechanism is explored in this paper. Three groups of emulsified asphalt mixtures (ARC-8 + SBR, SMA-5 + EVA, SMA-5 + SBR) were prepared by a conventional mixing process and novel mixing process. Marshall test of the emulsified asphalt mixture, CT scanning test of the emulsified asphalt mixture, workability test and analysis were manufactured and tested. The results show that, compared with conventional methods, the innovative forming method can increase the bulk density of the mixture and reduce the porosity, and thus improve its technical performance. The reason is that most of the water in the mixture of the innovative forming method sticks to the outer surface of the fine aggregate, and the water is more easily discharged. Secondly, the fine aggregate of the innovative forming method is directly mixed with the emulsion, and the volume is smaller. The emulsion wraps the fine aggregate in it due to the surface tension, which enhances the adhesion effect, thus improving the strength of the mixture.

Influence of ligands as chemical admixtures in the early hydration of sodium carbonate-activated blast furnace slag

Insufficient strength performance at early age impedes the use of sodium carbonate (SC) activator to produce sustainable blast furnace slag-based binders. To solve this issue, this study aimed to accelerate the early hydration kinetics of SC-activated slag system using ligand admixtures: triethanolamine (TEA), triisopropanolamine (TIPA), trisodium nitrilotriacetate (NTA), tetra potassium pyrophosphate (TKPP), and 2,3-dihydroxynapthalene (DHNP). Effect of ligands were investigated by isothermal calorimetry, compressive strength determinations, workability tests, XRD analysis, TGA, and batch dissolution tests. Results showed that the effect of the ligand on the reaction mechanism and strength development depends on the ligand functional group, concentration, and dissolution and metal complexing properties. Between the investigated ligands, 25 mM of DHNP accelerated the hydration kinetics by 28 h and produced 2-day strength of 41 MPa compared to the reference of only 2 MPa. Mechanism behind this acceleration is by affecting the ion activity product (IAP) of layered double hydroxides (LDHs) or C-(A)-S-H phases and not hindering the underlying carbonate salts (gaylussite, calcite) precipitation kinetics. These findings show the potential of ligands as admixtures in binder forming reactions and holds the key to potentially develop and fine tune sustainable low-CO2 binders.

Using tribological approach to assess production temperatures of asphalt binders

In this study, ball on three plates (BOTP) experiment has been used to propose an approach for evaluating the mixing and compaction temperatures of asphalt binder. The results are compared and correlated with equi-viscous- and workability- based methods to arrive at the proposed criterion. A viscosity grade binder, VG30, was modified with varying dosages of Sasobit and Rediset, and the study was executed considering two different types of aggregates (Granite and Dolerite). It was found that warm mix asphalt (WMA) binders can reduce the production temperatures of VG30, irrespective of the test methodology. Equi-viscous method was found to be inappropriate in the quantification of the production temperatures of WMA binders. Workability test results indicated that reduction in mixing and compaction temperatures is a function of the type of warm mix additive, dosages used, and aggregate source. Based on the variability of test parameters in BOTP test, a normal load of “1 N” and a sliding speed of “0.3 m/s” were found to give consistent results of coefficient of friction (CoF). The effect of plate type (Granite, Dolerite, and steel) on the values of CoF was found to be insignificant, and the use of steel plates was recommended. The results of BOTP and workability were in good agreement with each other. Temperature ranges corresponding to the CoF of “0.255–0.282” and “0.317–0.350” are proposed for assessing the mixing and compaction temperatures, respectively.

Ecological cement: replacement of sugarcane bagasse ash derived from the sugar and alcohol industry

Untreated sugarcane bagasse ash (CBCA) from two plants was investigated as a partial replacement for Portland cement (CP) with the aim of reducing environmental problems arising from clinker production by evaluating the feasibility of use as a supplementary cementitious material with pozzolanic reactivity. Mortars and pastes were produced with replacement rates of 25%, 30% and 35% of CBCA, with cures of 7, 14, 28, 90 and 180 days. The mortars were characterized in a fresh state through workability testing and in a hardened state through mechanical performance through compression and flexural tensile tests, water absorption and void index. The chemical composition, mineralogical composition, thermal analysis and formation of hydrate phases were carried out on the pastes and both ash. The ash tests showed that the CBCA-CM presented an amorphous halo and that it consumed portlandite in the process of forming the paste hydrates at 28 and 90 days. Mechanical performance tests showed that the ash has lower resistance at short ages and surpassed the control sample at long ages.