Performance of Silica Gel as Moisture Removal from Mortar

Silica gels are widely used as a desiccant to protect the product from moisture damage, which has capacity to absorb moisture from surrounding at level of 100% based on its own weight. Due to this performance, an innovative approach has been taken by applying the silica gel as moisture absorbance from mortar layer. The main objective of this research is to study the performance of silica gel as moisture absorption material that mainly to reduce the surface moisture of tested mortar samples. A series of procedures for experimental work has been designed purposely for this study. Three mortar samples with size of 300mm x 300mm x 50mm were prepared accordingly for each of sample with water-cement ratio of 0.40, 0.45 and 0.50. Initially, mortar samples were ponded with three liters of fresh water for period of 24-hours, and excess water were removed once completed. Then, data of surface moisture of mortar samples together with weight of silica gel was measured and collected simultaneously every 30 minutes for 6 hours. Experimental study found that S3, mortar with w/c of 0.5 had experienced the highest reduction of surface moisture rate of 0.047%/min due to the presence of silica gel. Silica gel, G2 that placed at the mortar with w/c of 0.45 has the highest rate of absorption of 0.119gram/min. When the number of usage increases, the performance of silica gel reduces. Lastly, a relationship is determined that as the surface moisture of tested mortar samples decreases, the weight of silica gel increases. As for the conclusion, selected silica gel showed a potential to be applied as moisture removal material for mortar, which then prevents the growth of mould or fungi

Settlement reduction of dredged marine soils (DMS) admixed with cement & waste granular materials (WGM): 1-D compressibility study

Dredged marine soils (DMS) are considered as geo-waste and commonly disposed far into the sea. Environmental impacts raised from dredging such as turbidity and disturbance of marine ecosystem had increased the social demand to reuse DMS in engineering application. Typically, DMS have low shear strength and low bearing capacity. Hence, the DMS could be strengthened up by soil solidification. In present study, waste granular materials (WGM) such as coal bottom ash (BA) and palm oil clinker (POC) were utilized as additional binder to cement. The DMS were solidified with 3 series of admixtures; namely cement and/or WGM. The factor that influenced the compressibility of the soil sample such as percentages of admixtures were considered. Proportioned samples of 10, 15 and 20 % of cement, and/or 50 and 150 % of WGM of dry weight of DMS were subjected to one-dimensional oedometer test. The test samples were cured for 7 days in room temperature. Results show that cement- and WGM-admixed DMS have reduced the soil’s compressibility considerably than the untreated sample. As expected, the cemented soil had significantly reduced the settlement better than WGM-admixed soil. Hence, homogeneous samples of 15C50BA and 10C100POC produced almost similar reduction of compressibility as sample 20C. Therefore, reusing WGM as partial replacement of cement in DMS could provide beneficial reuse of these materials

Experimental Evaluation on Physical and Mechanical Properties of Concrete Containing Green Mussel Shell (Perna viridis) Powder as an Admixture

Mussel shell is a type of waste that is generated abundantly. However, the presence of chemical components such as calcium (CaCO3) in mussel shells has shown its potential as filler materials in concrete designing. Therefore, this paper presents the experimental result for the physical and mechanical properties of concrete containing 1%, 2%, 3% and 4% Mussel Shell Powder (MSP) as additional material under 2.73% sodium chloride solution. The MSP has been cleaned, grinded and sieved 75μm sizes in order to obtain its final product. Compressive strength, split tensile, and capillary water absorption were determined. Statistical analysis was performed to investigate the correlation and level of significance using IBM SPSS in determining the optimal mix design for modified concrete. The performance of MSP concrete and control specimens are the main factor that been observed in this study. The increment percentages of MSP in concrete had led to reduce on its mechanical strength, however improved in its absorption rates. According to statistical analysis, it shows that low MSP percentages giving a significant value for compressive strength and very strong correlation coefficient compared to control specimens, thus it indicated minimum MSP percentages are more potential in improving concrete physical and mechanical performance

Experimental Evaluation on Physical and Mechanical Properties of Concrete Containing Green Mussel Shell (Perna viridis) Powder as an Admixture

Mussel shell is a type of waste that is generated abundantly. However, the presence of chemical components such as calcium (CaCO3) in mussel shells has shown its potential as filler materials in concrete designing. Therefore, this paper presents the experimental result for the physical and mechanical properties of concrete containing 1%, 2%, 3% and 4% Mussel Shell Powder (MSP) as additional material under 2.73% sodium chloride solution. The MSP has been cleaned, grinded and sieved 75μm sizes in order to obtain its final product. Compressive strength, split tensile, and capillary water absorption were determined. Statistical analysis was performed to investigate the correlation and level of significance using IBM SPSS in determining the optimal mix design for modified concrete. The performance of MSP concrete and control specimens are the main factor that been observed in this study. The increment percentages of MSP in concrete had led to reduce on its mechanical strength, however improved in its absorption rates. According to statistical analysis, it shows that low MSP percentages giving a significant value for compressive strength and very strong correlation coefficient compared to control specimens, thus it indicated minimum MSP percentages are more potential in improving concrete physical and mechanical performance

Statistical optimization of titanium recovery from drinking water treatment residue using response surface methodology

Water treatment plants generate vast amounts of sludge and its disposal is one of the most expensive and environmentally problematic challenges worldwide. As sludge from water treatment plants contains a considerable amount of titanium, both can create serious environmental concerns. In this study, the potential to recover titanium from drinking water treatment residue was explored through acid leaching technique. Statistical design for the optimization of titanium recovery was proposed using response surface methodology (RSM) based on a five-level central composite design (CCD). Three independent variables were investigated, namely the acid concentration (3 M–7 M), temperature (40 °C – 80 °C) and solid/liquid ratio (0.005–0.02 g/mL). According to the analysis of variance (ANOVA), the p-value (<0.0001) indicated the designed model was highly significant. Optimization using RSM gave the best fit between validated and predicted data as elucidated by the coefficient of determination with R2 values of 0.9965. However, acid concentration and solid/liquid ratio showed an initial increase in titanium recovery followed by recovery reduction with increasing concentration and ratio. Quadratic RSM predicted the maximum recovery of titanium to be 67.73% at optimal conditions of 5.5 M acid concentration, at a temperature of 62 °C with a solid/liquid ratio of 0.01 g/mL. The verification experiments gave an average of 66.23% recovery of titanium, thus indicating that the successfully developed model to predict the response. This process development has significant importance to reduce the cost of waste disposal, environmental protection, and recovery of economically valuable products