A study was conducted to investigate the suitability of commonly used materials in Goma, DR Congo for concrete production. The objectives of the study were to characterize the raw materials and determine their optimal use for desired resistances. Idjwi sand used, with a fineness modulus of 2.53 and a sand equivalent of 83, was found to be suitable for concrete production. Volcanic origin gravel was well graded but required consideration for its water absorption coefficient of 13.5%. Nyiragongo and Hima cements met standard requirements. Compression tests were carried out on laboratory specimens made using the Dreux Gorisse method, and material quantification results were used to create a table for 1 m3 of concrete based on desired resistances.
This article studies the effect of stabilization through incorporation of cement and lime on the bearing capacity of soil from BUGANGA in the Democratic Republic of Congo, with the aim of using it in road construction. Physical, identification, compaction, and bearing tests were carried out in the laboratory on the natural soil as well as after stabilization. The results show that the soil is a fine, sandy clay with low plasticity consisting of 47.25% fines and has low bearing capacity. The addition of cement and lime increases the soil bearing capacity, with cement being more effective than lime. With 10% cement, the CBR rate increases from 5.37% to 46.32%, while with 10% lime, it increases from 5.37% to 28.916%. Soil stabilized with 10% cement or lime is suitable for use as a foundation layer for paved roads, while that stabilized with 5% cement or lime is suitable for platform layers for roads.
This article presents the results of a study on the behavior of the compressive strength of a reference concrete formulated by the Dreux-Gorisse method, varying the dosage of water and cement by +/-10%, +/-20%, and +/-30%. The strength obtained for the reference concrete was 13.04MPa. However, an excessive change in the water dosage resulted in strengths of 8.438MPa, 7.05MPa, and 4.73MPa respectively for the dosages of +10%, +20%, and +30%. A deficient change in water dosage produced strengths of 14.418MPa, 15.465MPa, and 17.11MPa for the dosages of -10%, -20%, and -30%. For an excessive change in cement dosage, the strengths were 13.496MPa, 15.936MPa, and 21.575MPa respectively for the dosages of +10%, +20%, and +30%. A deficient change in the cement dosage showed strengths of 6.271MPa, 5.26MPa, and 3.207MPa for the dosages of -10%, -20%, and -30%. These results demonstrate that variations in these two components significantly affect the compressive strength of concrete. However, the change in cement dosage has a far greater impact on compressive strength than that of water.
Show abstract
Full Text
