Civil Engineering materials

This research work aims at the experimental analysis of engineering properties of some selected African timber species for sustainable building development. A well-designed questionnaire distributed to the correspondents was used to select the test samples. using availability and demand of the identified species, Mitragyna ciliata (Abura), Khaya senegalensis (Mahogany) and Terminalia superba (White Afarara) respectively were discovered as the three dorminant higher known species while Funtumia ebrifu (Ire), pterocarpus erinaceus (Madoobiya) and Albizia labbek (Ayinre) the three dorminant lesser known timber species. Samples of these species were obtained from Rijia lemu timber market, Kano Nigeria. Several experimental tests were conducted to determine the engineering properties of the samples in line with EN13183-1, EN408 and ASTM D193, using three-and four-point bending strength test methods. The formulated properties were used to acquire the characteristic values of the engineering properties in corespondant with EN384. The remaining engineering properties were calculated from the empirical formular given in EN338. Mitragyna ciliate was classified to C20, Khaya senegalensis to D35, Terminalia superba C14, Funtumia ebrifu D24, pterocarpus erinaceus D50 and Albizia labbek to class D40. The software EasyFit was used to create Stochastic probability distribution models on the S. E. Kelechi-Asumba, O. A. U. Uche, I. P. Okokpujie and M. Udo http://www.iaeme.com/IJCIET/index.asp 190 editor@iaeme.com reference properties of the timber species in which Kolmogorov Smirnov test was the supporting distribution, which indicates that most suitable distribution for bending strength, modulus of elasticity and density was weibull, gumbel and lognormal distributions respectively. However, the questionnaire analysis indicates specie popularity as the major factor for the increased demand pressure on the higher known species instead of engineering properties. Therefore, for sustainable building development the use of lesser known timber species with good engineering properties should be encourage so as to reduce the escalating demand pressure on the higher known species to prevent the species from going into extinction.

This research work aims at the experimental analysis of engineering properties of some selected African timber species for sustainable building development. A well-designed questionnaire distributed to the correspondents was used to select the test samples. using availability and demand of the identified species, Mitragyna ciliata (Abura), Khaya senegalensis (Mahogany) and Terminalia superba (White Afarara) respectively were discovered as the three dorminant higher known species while Funtumia ebrifu (Ire), pterocarpus erinaceus (Madoobiya) and Albizia labbek (Ayinre) the three dorminant lesser known timber species. Samples of these species were obtained from Rijia lemu timber market, Kano Nigeria. Several experimental tests were conducted to determine the engineering properties of the samples in line with EN13183-1, EN408 and ASTM D193, using three-and four-point bending strength test methods. The formulated properties were used to acquire the characteristic values of the engineering properties in corespondant with EN384. The remaining engineering properties were calculated from the empirical formular given in EN338. Mitragyna ciliate was classified to C20, Khaya senegalensis to D35, Terminalia superba C14, Funtumia ebrifu D24, pterocarpus erinaceus D50 and Albizia labbek to class D40. The software EasyFit was used to create Stochastic probability distribution models on the S. E. Kelechi-Asumba, O. A. U. Uche, I. P. Okokpujie and M. Udo http://www.iaeme.com/IJCIET/index.asp 190 editor@iaeme.com reference properties of the timber species in which Kolmogorov Smirnov test was the supporting distribution, which indicates that most suitable distribution for bending strength, modulus of elasticity and density was weibull, gumbel and lognormal distributions respectively. However, the questionnaire analysis indicates specie popularity as the major factor for the increased demand pressure on the higher known species instead of engineering properties. Therefore, for sustainable building development the use of lesser known timber species with good engineering properties should be encourage so as to reduce the escalating demand pressure on the higher known species to prevent the species from going into extinction.

This paper presents the result of on the engineering properties of higher and lesser known timber species in Kano market. The specimens for the test were selected using a well structured questionnaire administered to the target audience. Specimens of the selected three most higher known (Abura, Afara and Mahogany) and three most lesser known (Ire, Madoobiya, Ayinre) timber species were obtained from the timber shed at the famous Rijyar lemo timber market, Kano Nigeria. Laboratory experiments were conducted to determine the reference engineering properties of the specimens in accordance with EN13183-1, EN408 and ASTM D193, using three and four point bending strength test methods. From the results of the test, the three higher known species were classified as C20 (Mitragyna ciliate), D35 (Khaya senegalensis), C14 (Terminalia superba) in terms of strength while the lesser known species were classified as D24 (Funtumia ebrifu), D50 (pterocarpus erinaceus) and D40 (Albizia labbek). It confirms that though the three later species was of lesser known species but is of higher strength than the higher known species. Stochastic probability distribution models were developed on the reference engineering properties of the timber species using Simulation package EasyFit in which Kolmogorov Smirnov test was considered as the supporting distribution. It shows the best distribution

This paper presents the findings of an investigation on the influence of recycled aggregate concrete (RCA) as a substitute for virgin coarse aggregate in the compressive strength oplain concrete. Recycled aggregate concretes were produced together with virgin coarse aggregates and subjected to empirical tests which include grading, specific gravity, bulk density, water absorption, aggregate impact value (AIV) and aggregate crushing value (ACV) to ascertain their performances. Mix design was carried out for grade 30 concrete according to DoE (1975) and RCA percentages of 0, 25, 50, 75, and 100 were used in replacing the virgin aggregate proportion in the mix. The test results showed that the use of recycled concrete aggregate (RCA) reduces the compressive strength and this reduction increases with the increase in percentage of the RCA. Maximum decrement of about 33% in strength or about 67% of compressive strength development occurs when 100% of RCA was used as substitute to virgin coarse aggregate. It also reveals that about 25% of virgin coarse aggregate can be replaced with RCA in structural concrete work with out compromising the characteristic strength of the concrete. This result will not only eliminate the development of waste stockpiles of concrete as recycled material but also elicit the use of RCA in concrete work, thus providing environmentally friendly and economically viable solution as substitute for virgin aggregate as well as provide savings in the final cost of projects. KEY WORDS: Cement, Concrete, Virgin aggregates, Recycled concrete aggregates (RCA), compressive strength. INTRODUCTION The need and importance of concrete in construction industry is ever increasing since its discovery. Lomborg (2007) reported that the use of concrete is more than any other man made material on the planet. As about 2005, six billion cubic meters of concrete are made each year with countries like China currently consuming about 40% of world cement production, (Wikipedia, (2007). Most of the times, facilities constructed using concrete materials need to be repaired or replaced with passing time either because their end of service life is reached or the original design no longer satisfy the needs due to the growth in population or traffic or even an error in construction. These activities have always led to construction, demolition and excavation waste. The waste materials does not only constitute environmental problem but also put pressure on the available constituent materials used in concrete production-like the aggregate. The facts have remained how do we satisfy the growing demand for construction aggregates and, secondly how do we take care of the ever increasing amount of construction waste. FHWA (2004), report shows that two billion tonnes of aggregate are produced each year in the United States and production is expected to increase to more than 2.5 billion tonnes per year by the year 2020. This has raised concerns about the availability of natural aggregates and where they will find new aggregate sources.

The paper presents the results of experimental investigation on the properties of Aluminum long-span roofing sheets used in building construction in Nigeria. The determination of the properties was done in accordance with ASTM E-466(2000) and NIS 488(2004) using specimens manufactured by three most common aluminum roof material producers in Nigeria. The three most common gauges: 0.45, 0.55 and 0.70 were chosen for the investigation. The results of the tests revealed that the tensile strength, flexural strength and the impact resistance properties increase as the thickness of the aluminum sheet materials increases. The specific gravity of the specimens, also, increases with the thickness of the materials. These results are in consistency with the ASTM standard. It is also evident from the results that the specimen gauge of 0.45 failed to meet the ASTM E-466 and NIS 488 standards for all the variants of the roofing sheets. It is therefore recommended that 0.55 gauge should be the minimum thickness for structural aluminum roofing sheets in the Nigerian building industry.