Assessment of Sanaga and Nyong River Sand Properties as a Locally Available Raw Materials for the CEN EN 196–1 Standard Sand Production
摘要
In the present study, three samples of sand (fine, Sanaga and Nyong sand) were characterized to access their use as raw material for the local production of CEN EN 196–1 standard sand. Mineralogical, chemical, granulometry, and Physico- mechanical properties such as compressive and flexural strength test were analysed. The coarse sand from the Sanaga and Nyong rivers show low SiO2 content (81.89% and 83.91%) compared with the minimum required (97%), while alluvial sand has SiO2 content of over 95%. The SiO2 content of the washed fine sand is higher than 95% and the sum of Fe2O3 + Al2O3 + P2O5 is slightly higher than 2% (Fe2O3 + Al2O3 + P2O5 = 2.15%). Their granulometry respect the granular range of CEN EN 196–1 sands which is 6% for Sanaga sand and 14% for Nyong sand. Compressive strengths at 28 days represent 93% to 97% of the strength of specimens containing the certified CEN EN 196–1 sand, always taken as the reference in this study. Particle size analysis results show that before the standard sand formulation phase, the Sanaga sand contains 20% gravel, 79% coarse sand with an Mf well above 2.8. The raw curves before and after washing for Nyong sand and fine sand show a loss of solid particles of around 4% and 6% respectively. The low proportions of 1.6 mm (0.2% for FS and 1.3% for NS), 1 mm (1.7% for FS) and 0.08 mm (0.6% for SS and 3.3% for NS) sieve rejects did not favour the formulation of large quantities of sand bags for each of the sands analysed individually. It is concluded that Sanaga and Nyong sands can be used to formulate EN 196–1 sand, but an average coefficient of 1,05 should be applied to the experimental strength to obtain the final strength in compression.