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Bamboo is a rapid renewable plant that has a fast growth rate as compared to trees, which increases its suitability to be used as a sustainable source for wood industry, especially in construction works. Due to the lack of understanding on bamboo properties, the utilization of bamboo in construction has always been neglected. This paper presents an investigation on the mechanical properties of four species of treated bamboos that are available in Malaysia, which include Bambusa Vulgaris, Dendrocalamus Asper, Schizostachyum Grande, and Gigantochloa Scortechinii. A mechanical testing was carried out in various parts along the culm of these bamboo species in order to examine the differences of their compressive strength and tensile strength. The strength development and moisture content of these bamboo species were also monitored at a five-month interval. The results showed that Bambusa Vulgaris, Dendrocalamus Asper, and Gigantochloa Scortechinii possess excellent mechanical properties in compression and tensile strength, which indicate a good quality to be used as a construction material. As bamboo offers promising advantages, thus, it is suitable to be used as a substitute in place of structural timber in construction, which indirectly facilitates the preservation of the global environment.

This present study evaluates the effect of silica modulus (Ms) and curing temperature on strengths and the microstructures of binary blended alkali-activated volcanic ash and limestone powder mortar. Mortar samples were prepared using mass ratio of combined Na2SiO3(aq)/10 M NaOH(aq) of 0.5 to 1.5 at an interval of 0.25, corresponding to Ms of 0.52, 0.72, 0.89, 1.05 and 1.18, respectively, and sole 10 M NaOH(aq). Samples were then subjected to ambient room temperature, and the oven-cured temperature was maintained from 45 to 90 °C at an interval of 15 °C for 24 h. The maximum achievable 28-day strength was 27 MPa at Ms value of 0.89 cured at 75 °C. Samples synthesised with the sole 10 M NaOH(aq) activator resulted in a binder with a low 28-day compressive strength (15 MPa) compared to combined usage of Na2SiO3(aq)/10 M NaOH(aq) activators. Results further revealed that curing at low temperatures (25 °C to 45 °C) does not favour strength development, whereas higher curing temperature positively enhanced strength development. More than 70% of the 28-day compressive strength could be achieved within 12 h of curing with the usage of combined Na2SiO3(aq)/10 M NaOH(aq). XRD, FTIR and SEM + EDX characterisations revealed that activation with combined Na2SiO3(aq)/10 M NaOH(aq) leads to the formation of anorthite (CaAl2Si2O8), gehlenite (CaO.Al2O3.SiO2) and albite (NaAlSi3O8) that improve the amorphosity, homogeneity and microstructural density of the binder compared to that of samples synthesised with sole 10 M NaOH(aq).

This paper presents the outcome of work conducted to develop models for the prediction of compressive strength (CS) of alkali-activated limestone powder and natural pozzolan mortar (AALNM) using hybrid genetic algorithm (GA) and support vector regression (SVR) algorithm, for the first time. The developed hybrid GA-SVR-CS1, GA-SVR-CS3, and GA-SVR-CS14 models are capable of estimating the one-day, three-day, and 14-day compressive strength, respectively, of AALNM up to 96.64%, 90.84%, and 93.40% degree of accuracy as measured on the basis of correlation coefficient between the measured and estimated values for a set of data that is excluded from training and testing phase of the model development. The developed hybrid GA-SVR-CS28E model estimates the 28-days compressive strength of AALNM using the 14-days strength, it performs better than hybrid GA-SVR-CS28C model, hybrid GA-SVR-CS28B model, hybrid GA-SVR-CS28A model, and hybrid GA-SVR-CS28D model that respectively estimates the 28-day compressive strength using three-day strength, one day-strength, all the descriptors and seven day-strength with performance improvement of 103.51%, 124.47%, 149.94%, and 262.08% on the basis of root mean square error. The outcome of this work will promote the use of environment-friendly concrete with excellent strength and provide effective as well as efficient ways of modeling the compressive strength of concrete.

As the fastest growing plant with high tensile strength, bamboo provides an excellent alternative material to replace steel reinforcement in a concrete structure. However, the bond of bamboo embedded in concrete is very poor due to its surface properties and swell–shrink behaviors, especially when embedded in ordinary Portland cement concrete (OPCC). Thus, this paper presents the experimental investigation on the bond performance of deformed and undeformed bamboo species of Bambusa vulgaris strips embedded in fly ash geopolymer concrete (FAGC). Undeformed bamboo strips with and without nodes were compared to deformed bamboo strips in a corrugated and Galvanized Iron (G.I) rolled wired form in the pull-out test to study the mechanical interlocking effect on the bond performance of bamboo strips embedded in concrete. The groove on the corrugated bamboo strip was made using a router machine, while the wired bamboo was produced by wrapping the G.I wire along the bamboo strip. The difference in groove and wire spacing of the deformed bamboo strip on the bond strength was also observed. The result showed that the geometry of the bamboo strip had a significant effect on the bond performance, with the deformed bamboo strip outperforming the undeformed bamboo strip. In addition, the utilization of FAGC could also reduce the moisture absorption by the bamboo strip. Thus, these results showed that using bamboo strips in FAGC is feasible, contributing to a promising approach for full utilization of bamboo and industrial waste products such as fly ash as construction materials.

The development of sustainable, environmentally friendly alkali-activated binder has emerged as an alternative to ordinary Portland cement. The engineering and durability properties of alkali-activated binder using various precursor combinations have been investigated; however, no study has focused on the impact of high-volume natural pozzolan (NP) on the acid resistance of alkali-activated NP and limestone powder. Therefore, the current study assesses the impact of high-volume natural pozzolan (volcanic ash) on the durability properties of alkali-activated natural pozzolan (NP) and limestone powder (LSP) mortar by immersion in 6% H2SO4 for 365 days. The samples were prepared with different binder ratios using alkaline activators (10 M NaOH(aq) and Na2SO4) combined in a 1:1 ratio and cured at 75 °C. NP was combined with the LSP at three different combinations: NP:LSP = 40:60 (AAN40L60), 50:50 (AAN50L50), and 60:40 (AAN60L40), representing low-volume, balanced, and high-volume binder combinations. Water absorption, weight change, and compressive strength were examined. The microstructural changes were also investigated using FTIR, XRD, and SEM/EDS characterization tools. Visual examination showed insignificant deterioration in the sample with excess natural pozzolan (AAN60L40) after 1 year of acid exposure, and the maximum residual strengths were 20.8 MPa and 6.68 MPa in AAN60L40 and AAN40L60 with mass gain (1.37%) and loss (10.64%), respectively. The high sulfuric acid resistance of AAN60L40 mortar was attributed to the high Ca/Si = 10 within the C-A-S-H and N-A-S-H formed. The low residual strength recorded in AAN40L60 was a result of gypsum formation from an acid attack of calcium-dominated limestone powder. The controlling factor for the resistance of the binder to acid corrosion was the NP/LSP ratio, whose factor below 0.6 caused significant debilitating effects.

This paper presents the experimental results on the behavior of fly ash geopolymer concrete incorporating bamboo ash on the desired temperature (200 °C to 800 °C). Different amounts of bamboo ash were investigated and fly ash geopolymer concrete was considered as the control sample. The geopolymer was synthesized with sodium hydroxide and sodium silicate solutions. Ultrasonic pulse velocity, weight loss, and residual compressive strength were determined, and all samples were tested with two different cooling approaches i.e., an air-cooling (AC) and water-cooling (WC) regime. Results from these tests show that with the addition of 5% bamboo ash in fly ash, geopolymer exhibited a 5 MPa (53%) and 5.65 MPa (66%) improvement in residual strength, as well as 940 m/s (76%) and 727 m/s (53%) greater ultrasonic pulse velocity in AC and WC, respectively, at 800 °C when compared with control samples. Thus, bamboo ash can be one of the alternatives to geopolymer concrete when it faces exposure to high temperatures.

The use of cold-formed steel (CFS) as a frame in a single-story structure building system has been widely applied. However, the use of cold-formed steel for multi-story buildings is still constrained in the structure system, especially column. In the conventional structure, columns used in large dimension, height, h> 150 mm and thickness, t> 1.2 mm which makes the construction cost expensive. An innovation of cold-formed steel combine profile into one compression member unit is very interesting to study, furthermore, previous research provides information on a variety of cold-formed steel behaviors with small dimensions of height, h <150 mm and thickness, t <1mm, which can be developed into columns with greater strength. There have been a lot of research on behavior on cold-formed steel, but the study on screw optimization especially on combined profile to become compression member still need to develop. From the compression test on double profile back to back and flange to flange length, l = 300 mm and screw distance variation, 25 to 150 mm with 50 mm intervals, indicating a response similarity at screw spacing 25 mm, 50 mm and 75 mm, while the screw distance 100 mm, 125 mm and 150 mm experienced backline capacity.

Arabic gum biopolymer (AGB) has recently been demonstrated to improve mechanical and physical properties of fresh and hardened concrete which makes it a promising sustainable and environmentally friendly water-reducing admixture. The present work focuses on the effect of added AGB on the workability, setting time, and durability of concrete. Furthermore, a microstructure analysis is conducted to provide objective evidence and support for previous findings and hypothetic interpretations. Flow table experiments are conducted on Portland cement mortar mixed with different percentages of AGB to evaluate the workability. The initial setting time of cement paste is measured for different AGB contents. X-ray fluorescence tests are performed on cement-AGB mix powder to determine its chemical composition. Carbonation depth in AGB concrete samples is estimated to assess durability. AGB-added cement powder was subjected to X-ray diffraction and SEM tests to determine the rate of hydration and to expose the microstructure properties of AGB cement mix and help explain its macroscopic behavior, respectively.

The use of materials of vegetal origin is increasingly being promoted in many industries due to their cost effectiveness and the rising sensitivity to environmental protection and sustainability. Arabic Gum Biopolymer (AGB) is a wild plant byproduct that is abundantly found in Sudan and is also produced in other African countries. It has long been used in various industries. However, its utilization is very limited in the construction sector although there appears to be a significant potential for use of AGB in the building industry. As an example, there is evidence that AGB may be an effective additive to concrete mixes that would improve fresh and hardened concrete properties. The aim of the present work is to provide further experimental evidence on the improvement that can be achieved in the physical and mechanical properties of hardened concrete when AGB is added to the mixture. The experimental results show a significant reduction in permeability for an optimum percentage of AGB and an increase in flexural and tensile strength and in the elastic modulus.

Bamboo is a naturally available construction material and one of the fastest growing plant compared with the tree, which increases its suitability to be used as a sustainable source for wood industry, especially in construction works. Due to the lack of understanding on bamboo properties and lack of design standard, the utilization of bamboo in construction has always been neglected. This paper presents an investigation on the buckling behaviour of three species treated bamboos that are available in Malaysia, which included Bambusa Vulgaris, Dendrocalamus Asper, and Gigantochloa Scortechinii. Furthermore, a design method based on Perry-Robertson formula was proposed for compressive buckling of the bamboo. The experimental compressive buckling on 15 columns was conducted to investigate the buckling behaviours and the design procedure was developed by using the test data results. It was shown that for Dendrocalamus Asper, the model factors of the proposed design method was 1.16 while Bambusa Vulgaris was 1.15 and Gigantochloa Scortechinii was also 1.15. As result, the proposed design method was shown to be adequate and also was successfully calibrated against the test data. Thus, the advantages of bamboo in the structural application should be fully utilized to build light, strong bamboo structure.