Physical and mechanical properties of mortars containing date palm fibers

This paper presents the results of a study conducted to investigate the effects of incorporating Sefri Date Palm Leave Fibers (SDPLF) into the mortar. A total of seven mixtures were prepared and tested. SDPLF were collected from local farms. The fibers were then cleaned, dried, and cut to different sizes of 10 mm, 20 mm, and 50 mm, maintaining the same individual fiber width of approximately 5±2 mm. The content of SDPLF in mortars was kept to 1% and 3% by mass. The physical and mechanical properties of SDPLF fibers and SDPLF mortars were investigated. The compressive strength at 7, 14, and 28 days was determined. The water absorption rate test was carried out on mortars containing 1% SDPLF fibers. The results showed that mortars with SDPLF have lower workability, lower density, and lower compressive strength as compared to control mortars. However, they are still acceptable for use in construction works. Mortars containing 10 mm and 20 mm SDPLF fibers by mass showed significant improvement in terms of water absorption rate as compared to the control mortar.

Performance analysis of gravity chemical blockers in the treatment of rising damp in masonry walls

The objective of this work is the performance analysis of the rising damp treatment in walls, through the use of chemical blockers (i.e., crystallizing and water repellant) available in the Brazilian market, with their introduction by gravity. As there are no standardized tests for such a study, experiments conducted by other researchers were used as a reference. The evaluation of the rising damp was achieved by the calculation of the water absorption rate in the specimens, allied with the images obtained by the thermographic camera. From the results, it was concluded that the treatment did not completely reduce the pathological manifestation in the walls, but both products performed well and managed to reduce the water absorption rate considerably.

Analysis on the barrier properties of thin film PLA/PBAT reinforced with microcrystalline cellulose

In recent times, awareness on plastic pollution had increase which brings innovation on new productions to be environmental friendly. Various polymers has been used to analyse the suitability to produce thin films. In this study, Poly lactic acid (PLA) and Polybutylene adipate terephthalate (PBAT) reinforced with microcrystalline cellulose (MCC) were investigated. MCC were produced from selected bamboo for obtaining cellulose, then followed by an acidic hydrolysis process for the processing of microcrystalline cellulose (MCC). In this study, the thin film are focusing on the barrier properties such as water absorption, solvent resistance and absorption test. From the results shows that, the lowest rate of water absorption rate is 1.9% by 1% B-MCC/PLA/PBAT, meanwhile, the highest rate of water absorption is 60.1% by 5% C-MCC/PLA/PBAT. The water absorption rate decrease gradually with the decreasing of amount of MCC in the samples. Lastly, the thin film samples can resist with oleic acid solvents as the condition of thin film samples is still remain but they were not resistance with xylene as the thin film samples were shrinked and degraded. This thin film have a potential to replace the non-biodegradable petrochemical polymer based on their properties such as food contact, availability and cost.

The Physical and Mechanical Properties of Corn-based Bioplastic Films with Different Starch and Glycerol Content

Petroleum-based plastics have had a long history with varied materials and applications. However, the major drawback with these plastics is their harmful impact on the environment. Poor disposal management of these plastics have ultimately affected humans. Therefore, starch-based bioplastics have been widely used because of their renewability, sustainability and cost-effectiveness. This work investigated the effect of different concentrations of corn starch (10%, 15%, and 20% w/w of distilled water) and glycerol (20%, 30%, and 40% w/v of corn starch) on the properties of corn-based bioplastic films. Particularly, mechanical (tensile strength, Young’s modulus and elongation at break) and physical (water absorption rate and moisture content) properties were investigated. These films were prepared by the solvent casting method. It was demonstrated that the addition of 30% glycerol produced mechanical properties closest to the standard value, while films with a composition of 15% of corn starch had the most optimised value. Meanwhile, 20% glycerol and 20% corn starch produced a film with high strength and stiffness but lacked flexibility. Higher concentrations of starch and glycerol produced the highest moisture and water absorption rate. This was due to the highly hydrophilic nature of both corn starch and glycerol. However, the concentration of glycerol needs to be adjusted based on the intended use of the film. In conclusion, the concentration of corn starch and glycerol produced slightly different outcomes. Thus, the properties and application of the cornbased bioplastic films can be maximised by optimising the concentration of corn starch and glycerol.

Assessment of Sandcrete Blocks Quality in Owerri, Imo State, Nigeria

This study assessed the production management practice being adopted in the manufacture of quality sandcrete blocks in selected sampled parts of Owerri municipal, Imo State, Nigeria. Myriads of literature identify sandcrete blocks as a significant material being used in the building & civil engineering practice and assert that its application as a walling material cannot be over emphasized. Sandcrete block manufacturers in Owerri, Imo State were used for the assessment of the quality of their products in line with the Nigeria Industrial Standard (NIS) specifications. The study adopted field sampling, experimentations and work study methods to determine the compressive strength and water absorption rate properties of the selected sampled sandcrete blocks. The results of the study reveals among others that the mean compressive strength values obtained were as low as 1.92N/mm2, and about 17% water absorption rate from sampled commercial blocks. The results obtained did not compare favorably with the NIS specified acceptable minimum standard values. The study therefore underpinned poor production quality control practice as well as lack of impact of regulatory bodies in Imo State as among factors that contributed to the negative results obtained.

Weathering Features of A Five-Story Stone Pagoda Compared To Its Quarrying Site In Geumgolsan Mountain, Korea

Understanding the long- and short-term weathering features according to rock type is very important for maintaining the original form of stone heritages. In this study, the material characteristics of a deteriorated five-story stone pagoda were compared with those of fresh rocks from its quarrying site at nearby Geumgolsan Mountain, Korea to diagnose the degree of damage and develop a comprehensive interpretation of the weathering mechanism. The stone pagoda was built from lithic tuff comprising pumice and phenocrysts such as quartz, K-feldspar, plagioclase, and mica based on plagioclase substrates; the mineralogical and geochemical characteristics are similar to those of the fresh rocks. The lithic tuff of the stone pagoda demonstrated a low ultrasonic velocity of 2863 m/s and a high water absorption rate and porosity of 9.5% and 19.2%, respectively, which are poorer than the physical properties of the fresh rocks (i.e., ultrasonic velocity of 3336 m/s, water absorption rate of 8.65%, and porosity of 17.83%). The lithological characteristics and physical properties demonstrated a considerable influence on the weathering and stability of the stone pagoda. In particular, fragments of relatively weak pumice detached from the original rock to form cavities of various sizes. These cavities introduced moisture within the rock, which produced oxides and hydroxides of iron and manganese. In addition, contaminants such as dust, salt crystals, clay minerals, and microorganisms adhering to the surface of the stone pagoda accelerated its physical, chemical, and biological weathering. The results of this study will be important for realizing the stable and long-term conservation of the five-story stone pagoda at Geumgolsan Mountain.

CHARACTERIZATION OF MORTAR WITH PENNISETUM PURPUREUM ASHES AS CEMENT REPLACEMENT MATERIAL

In this study, the properties of mortar such as standard consistency, setting time, compressive strength, and water absorption rate were investigated. The cement was replaced with Pennisetum purpureum ashes (PPA) in different particle sizes and dosages. PPA was produced in greyish-white ash with total reactive oxides ranging from 37% to 41.1%. Pennisetum purpureum grass (PPG) was burned with a controlled process at 350 °C for the first 3 hours and 600 °C for another 3 hours at a heating rate of 10 °C/min. Then, PPG was ground in three different grinding durations (1, 3, and 6 hours) producing ashes with particle sizes of 10.58 µm, 10.25 µm, and 9.30 µm, respectively. The physical, chemical, and microstructural properties of PPA were evaluated through several tests; particle size analysis, X-ray diffraction analysis, loss on ignition, and chemical composition. Results indicated that PPA is more suitable for use as filling material as a substitute for cement than pozzolanic material as its reactive oxides are less than 50%. The 15% 6H-PPA at 28 days was found to be the optimum PPA replacement dosage and grinding time with cement as it achieved the highest strength and lower water absorption rate among all samples at 7 and 28 days. ABSTRAK: Kajian ini berkenaan sifat mortar seperti konsistensi standard, masa penyediaan, kekuatan menyeluruh, dan kadar penyerapan air. Simen ditukar dengan abu Pennisetum purpureum (PPA) dalam saiz partikel dan sukatan berbeza. PPA pula dihasilkan melalui habuk putih-kekelabuan dengan total reaktif oksida dengan julat purata 37% ke 41.1%. Rumput Pennisetum purpureum (PPG) dibakar dengan proses kawalan pada 350 °C selama 3 jam pertama dan 600 °C pada 3 jam berikutnya pada kadar pemanasan 10 °C/min. Kemudian, PPG dikisar dalam tiga tempoh kisaran berbeza (1, 3, dan 6 jam) menghasilkan abu dengan saiz partikel 10.58 µm, 10.25 µm, dan 9.30 µm, masing-masing. Fizikal, larutan kimia dan sifat struktur mikro PPA telah dikaji melalui pelbagai ujian; analisis saiz partikel, analisis pembelauan X-ray, kehilangan semasa penyalaan dan kandungan kimia. Dapatan kajian menunjukkan PPA adalah lebih sesuai digunakan sebagai material pengisian ganti kepada simen berbanding material pozzolanik kerana reaktif oksida adalah kurang daripada 50%. PPA adalah maksimum pada 15% 6H-PPA selama 28 hari, didapati lebih sesuai sebagai dos pengganti dan masa kisaran bersama simen, kerana kekuatan menyeluruh adalah paling tinggi dan kadar penyerapan air paling kurang antara semua sampel pada 7 dan 28 hari.

Effect of the Properties of Cordierite Support and Catalyst Slurry on the Catalytic Degradation of Toluene by Monolith Catalyst

Monolithic catalysts are widely used in industrial catalysis. However, in the preparation of monolithic catalyst, the most important catalyst coating has the problems of low upload rate and poor uniformity. In the present work, the effects of acid treatment of carrier on the upload rate and the effects of size of slurry and dispersant on the uniformity of coating were investigated. The weight loss rate and water absorption rate of cordierite, slurry stability, coating upload rate and catalytic performance were also tested. Characterization analysis was carried out by means of BET, SEM, Zeta potential, the laser grain-size analyzer. The results showed that the optimal performance of cordierite carrier could be obtained by heating the cordierite carrier with 20% HCl for 3 h; the water absorption rate could increase for more than 48.0%, and the upload rate could reach 14.5%. Pearson test showed that there was a moderate positive correlation between water absorption rate and upload rate. It was also found that reducing the particle size of the slurry (1.47 microns) and adding 4% dispersant PAA could effectively improve the stability of the suspension and the uniformity of the coating. When 20% HCl was used to pretreat, the toluene catalytic activity of the monolith catalyst prepared by cordierite increased, in which T10 and T90 both increased for about 5 ℃. At the same time, reducing particle size and adding dispersant could also promote the catalytic degradation efficiency to a certain extent.

Moisture Absorption Behavior and Adhesion Properties of GNP/Epoxy Nanocomposite Adhesives

In the current work, an attempt has been made to investigate the effect of Graphene Nanoplatelets (GNP) reinforcement to water absorption behavior and mechanical properties of adhesive bonding with epoxy. Epoxy adhesive with various GNP content (i.e., 0.0~2.0 wt%) was utilized to joint aluminum adherend subjected to various immersion periods (i.e., 0~60 days). Subsequently, the effect of GNP reinforcement on water uptake, water absorption rate and tensile shear strength was investigated. Depending on GNP content, two distinct behaviors in water uptake and moisture absorption rate have been observed; specimens with lower GNP content (0.5~1.0 wt%) have demonstrated increased/retention of water uptake and water absorption rate regardless of immersion period. Meanwhile, at higher GNP content (1.5~2.0 wt%), decreased water uptake and water absorption rate are generally observed. At similar GNP content, regardless of immersion periods, water immersed specimens generally demonstrate higher or retention of shear strength when compared to specimens at 0-day immersion period. These observations suggest that the relation between moisture absorption behavior and mechanical properties of GNP-reinforced adhesive with GNP content are rather complex which might be attributed to the interplay of several possible mechanisms.