Variation of Chemical Elements and Their Associations in Laterite Soil Profile

The objective of this study was to evaluate the variations of twelve chemical elements (Ni, Fe, Co, Mg, Mn, Al, Si, Zn, Ti, P, Ca and Cr) in laterite soil profiles from Wantulasi area in South East Sulawesi Province of Indonesia. Eighty four (84) samples of three profiles (i.e. each profile consists of eight samples) had been used to study their variations in soil using  the X-Ray Fluorescence (XRF). Results analysis of the chemical elements content in three profile using XRF indicated that there were good correlationsbetween the chemical elements in the soil profile with the significant correlations were found in Ni and Fe, Ni and Si, Ti and P, Fe and Al, and Co and Mn, respectively. On the other hand,the results of study showed that the variations of the chemical elements could be related to the enrichment and translocation of the elements  in soil profile and also their possibilities to be related with a given chemical elements in soil profile. Therefore, we suggest that the observed patterns in chemical elements with a good correlation in laterite profile can be used as proxies to integrate the evaluation of the chemical and physical weathering process based on the elements characteristics in soil profiles

Optimization of micro and nano palm oil fuel ash to determine the carbonation resistance of the concrete in accelerated condition

The carbonation rate of reinforced concrete is influenced by three parameters, namely temperature, relative humidity, and concentration of carbon dioxide (CO2) in the surroundings. As knowledge of the service lifespan of reinforced concrete is crucial in terms of corrosion, the carbonation process is important to study, and high-performance durable reinforced concretes can be produced to prolong the effects of corrosion. To examine carbonation resistance, accelerated carbonation testing was conducted in accordance with the standards of BS 1881-210:2013. In this study, 10-30% of micro palm oil fuel ash (mPOFA) and 0.5-1.5% of nano-POFA (nPOFA) were incorporated into concrete mixtures to determine the optimum amount for achieving the highest carbonation resistance after 28 days water curing and accelerated CO2 conditions up to 70 days of exposure. The effect of carbonation on concrete specimens with the inclusion of mPOFA and nPOFA was investigated. The carbonation depth was identified by phenolphthalein solution. The highest carbonation resistance of concrete was found after the inclusion of 10% mPOFA and 0.5% nPOFA, while the lowest carbonation resistance was found after the inclusion of 30% mPOFA and 1.5% nPOFA

Masonry compressive strength prediction using artificial neural networks

The masonry is not only included among the oldest building materials, but it is also the most widely used material due to its simple construction and low cost compared to the other modern building materials. Nevertheless, there is not yet a robust quantitative method, available in the literature, which can reliably predict its strength, based on the geometrical and mechanical characteristics of its components. This limitation is due to the highly nonlinear relation between the compressive strength of masonry and the geometrical and mechanical properties of the components of the masonry. In this paper, the application of artificial neural networks for predicting the compressive strength of masonry has been investigated. Specifically, back-propagation neural network models have been used for predicting the compressive strength of masonry prism based on experimental data available in the literature. The comparison of the derived results with the experimental findings demonstrates the ability of artificial neural networks to approximate the compressive strength of masonry walls in a reliable and robust manner.- (undefined

Water vapor transmission and waterproofing performance of concrete sealer and coating systems

This paper reports the water vapor transmission and waterproofing performance of a silane-based penetrating sealer (PS), two cementitious coatings (CC1 and CC2), and a polymeric coating (PC). The sealer and coating products were applied on 100-mm concrete cubes. In total, fifteen concrete cubes including the control specimens were prepared. The treated concrete cubes were tested to determine the ability of the selected products to improve waterproofing and to transmit water vapor. The correlation between water vapor transmission and waterproofing performance was also examined. Experimental results revealed that the cementitious coating CC2 had the lowest degree of water vapor transmission but the highest degree of waterproofing performance. In contrast, the highest degree of water vapor transmission but the lowest degree of waterproofing performance were observed for the cementitious coating CC1. The penetrating sealer PS provided greater water vapor transmission but lower waterproofing ability than the polymeric coating PC and the cementitious coating CC2. The best-performing coating with regard to water vapor transmission and waterproofing was the polymeric coating PC. Furthermore, the water vapor transmission and waterproofing performance of the sealer and coating systems were strongly correlated; this suggests that one of these two properties can be predicted by testing the other

Air content of self-consolidating concrete and its mortar phase including rice husk ash / Oro kiekis savitankiame betone ir jo skiedinio dalyje su ryžių lukštų pelenais

This paper presents the air content results of self-consolidating concrete (SCC) and its mortar phase including rice husk ash (RHA) as a supplementary cementing material. Moreover, this paper demonstrates a simple technique to determine the dosage of air-entraining admixture (AEA) required for the target air content in SCC. Different SCC mixtures were designed based on the water/binder (W/B) ratios of 0.30–0.50 and design air content of 4–8%. RHA was incorporated in the concretes substituting 0–30% of cement by weight. The mortars were formulated from the mixture proportions of the corresponding parent concretes and tested to determine the air content at various AEA dosages. The effects of W/B ratio and RHA content on the air content of both mortar and concrete were observed. The effect of mortar volume on the air content of concrete was also noticed. Besides, the AEA dosages required for the target air contents of concrete were estimated based on the equivalent mortar air contents. Later the air-entrained SCC mixtures were produced using AEA and tested for the air content. Test results exhibit that the air contents of both mortar and concrete were significantly influenced by the W/B ratio and RHA content. The concrete air content was also greatly influenced by its mortar volume. The AEA dosage increased with lower W/B ratio, higher RHA content, and greater mortar volume for the target air contents. In addition, the actual AEA dosages were consistent with the estimated AEA dosages of the concretes. An excellent correlation was observed between the actual and estimated AEA dosages. The strong correlation suggests that the AEA dosage needed for a target air content in concrete can be determined based on the equivalent air content of its mortar phase. Santrauka Straipsnyje pateikiami oro kiekio nustatymo savitankiame betone (SCC) ir jo skiedinio dalyje su ryžių lukštų pelenais (RHA), naudojamais kaip papildoma cementavimo medžiaga, rezultatai. Be to, pateikiamas paprastas būdas parinkti orą įsiurbiančio priedo (AEA) dozę, siekiant gauti reikalingą oro kiekį SCC. Suprojektuoti skirtingi SCC mišiniai su skirtingu vandens ir rišiklio (W/B) 0,30–0,50 santykiu ir numatytu 4–8 proc. oro kiekiu, RHA buvo dedamas į betoną pakeičiant 0–30 proc. cemento pagal masę. Skiediniai buvo formuojami pagal jiems artimo betono sudėtis ir oro kiekis juose bandomas su skirtingomis AEA dozėmis. Nustatyta W/B santykio ir RHA kiekio įtaka oro kiekiui tiek skiedinyje, tiek betone bei skiedinio tūrio įtaka oro kiekiui betone. Be to, AEA dozės, reikalingos numatytam oro kiekiui betone pasiekti, nustatytos pagal ekvivalentinį oro kiekį skiedinyje. Vėliau SCC mišiniai su orą įsiurbiančiu priedu buvo pagaminti naudojant AEA ir išbandytas juose esantis oro kiekis. Tyrimų rezultatai rodo, kad tiek skiedinį, tiek betono oro kiekį labai veikia W/B santykis ir RHA kiekis. Oro kiekį betone taip pat smarkiai veikia skiedinio tūris. Mažėjant W/B santykiui, didėjant RHA kiekiui ir skiedinio tūriui AEA dozė turi būti didinama norimam oro kiekiui pasiekti. Taip pat faktinės AEA dozės atitiko suskaičiuotas betonų AEA dozes. Tarp faktinių ir suskaičiuotų AEA dozių gauta labai gera koreliacija. Ji rodo, kad AEA dozę, reikalingą numatytam oro kiekiui betone pasiekti, galima skaičiuoti pagal ekvivalentinį oro kiekį šio betono skiedinio dalyje. Reikšminiai žodžiai: oro kiekis, orą įsiurbiantis priedas, betonas, mišinio sudėtis, skiedinys, ryžių lukštų pelena