土木環境工学ジャーナル

The self-compacted concrete is an innovative product in civil engineering field of India. The necessity of this product was felt by civil engineers to overcome in the issue of workmanship, in structural concreting of thickly/heavily re-in forced sections in execution of concreting. This product was first developed in Japan in 1997 and followed by Europe and U.S.A. Substantial research was carried out with regard to the properties of SCC Because of the well-controlled conditions; the introduction of SCC in the precast concrete industry was successful. With regard to the application in situ, the development is slower, because of the sensitivity of the product. In this paper the mechanical properties of SCC in comparison to conventional concrete are discussed. Examples of applications are shown, both for prefabricated concrete elements and in- situ structures. In this study the area has been covered is making the design mix of self-compacted concrete and it’s performance – economic comparisons with prevailing conventional grade of concrete of M-40 grade.

Pavement alternative evaluation is a key aspect in decision making process in transportation system planning, design and delivery. This study examined the Life-Cycle Cost Analysis (LCCA) model for flexible road pavement infrastructure delivery in a developing economy using 1.9 km urban road in Effurun Metropolis, Uvwie Local Government Area of Delta State of Nigeria as a case study. The overview of existing knowledge, the importance and evaluation of LCCA of pavement delivery is done. The Pavement delivery and design data used for this study, which were obtained from the Office of the Ministry of Works, Effurun, Delta State of Nigeria, included soil sub-grade CBR results, water content condition, soil type and grain size distribution, the reports of route investigation, vehicular traffic counts, and previous maintenance, material and market survey reports. The pavement design data previously used for the design and procurement of urban roads in the area were used for the design of three competing pavement alternatives models, viz: Hot Rolled Asphalt (HRA), Interlocking Concrete Block Pavement (ICBP) and a third; Do-nothing scenario pavement alternative. The Bill of Engineering Measurements and Evaluation (BEME) was developed for the designed alternative to compute their Life- Cycle Costs (LCCs) using present worth cost (PWC) method with varying interest rates in MS Excel software spread sheets for a design life of 20 years. Regression modeling for the three scenarios was done with computer software’s (SPSS and MS Excel) packages. The model’s data robustness was determined and found to be between 0.95-0.99. The model’s validity and sensitivity were also carried out. The study indicates a 43.8% cost savings with the ICBP alternative over the HRA option. The Do-nothing alternative is non–aesthetical and costliest due to the maintenance cost of reinstating the road structure. The models have significance value of less than 0.001(F) respectively. The developed LCCA template and model are applicable for investment studies and decision making as well as cost effectiveness assessment of pavement and bridge delivery.

Soil particle less than 75 microns can be analyzed for the distribution of various grains sizes of silt and clay. This is achieved through hydrometer test. In this study the effect of different dispersing agents on the hydrometer test were studied. Four different solutions of dispersing agent and soil samples were prepared. The first solution was prepared using 35 g of sodium hexa metaphosphate with 7 g of sodium carbonate (solution I). Second solution is prepared using only 40 g of sodium hexa metaphosphate per 1 litre of solution (solution II). Third solution is prepared using 40 g of sodium carbonate (solution III) and the fourth is prepared without using any dispersing agent rather, the two soil samples used were dissolved in distilled water (solution IV). After comparative analysis, solutions I and II were recommended as the best method for preparation of soil solution for hydrometer test. Percentage passing obtained for solution I differs from solutions II, III, IV by 3.20, 6.88 and 24.07 respectively; for sample A and 3.22, 11.1 and 19.52 respectively; for sample B. Solution I and II are consistent for both samples whereas solution III is not consistent showing that it depends on the nature of soil being dispersed. Therefore, sodium carbonate is added to solution I to reduce its hardness. The results obtained showed that solution I and II are recommended only as prescribed by BS and ASTM respectively.