Evaluation of the Properties of Local Sands Used in a Cement Mortar and in the Formulation of a Standard Sand to Test the Class of Cements
Brige Dublin Boussa Elenga,
Louis Ahouet,
Sylvain Ndinga Okina
Issue:
Volume 12, Issue 3, September 2023
Pages:
31-38
Received:
21 July 2023
Accepted:
5 August 2023
Published:
22 August 2023
Abstract: The aim of this work was to provide a better alternative to the problems of importing standardized sand and to make good use of local sand to produce a quality mortar. Sand samples taken from various locations in the city of Brazzaville were subjected to a number of laboratory tests and to two types of mortar formulation. The results obtained show that local sands (S1-S8) in their natural state are finer and cannot be used as standard sand for cement quality control. However, some local sands can be used in the manufacture of masonry mortar. The mechanical properties of mortars made with these sands are lower than those of mortars made with standard sand, but are strongly correlated with the latter. The reformulation of local sands (S1-S8) mixed with crushed sand S9 considerably improves the mechanical properties of the mortar, which are identical to those of standard sand. The mechanical strength of mortar based on local S3 sand enriched with crusher sand (0/5) is greater than that obtained with standard sand. Reformulated sand can be used as standard sand for cement quality control. The relationship in formulation 2 between the mechanical strength of mortar based on improved local S3 sand and that of standard sand can be used to test cements. Several studies show that it is sometimes difficult to obtain the expected compressive strength of a given cement with standard sand. For the 32.5R cement used, the sands (S1-S3, S5, S6) improved to crushed sand with formulation 2, produce standardized sands for testing cements.
Abstract: The aim of this work was to provide a better alternative to the problems of importing standardized sand and to make good use of local sand to produce a quality mortar. Sand samples taken from various locations in the city of Brazzaville were subjected to a number of laboratory tests and to two types of mortar formulation. The results obtained show ...
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Impact of Blast Furnace Slags as a Substitute Aggregate on the Strength of Hydraulic Concretes
Mouhamed Lamine Cherif Aidara,
Adama Dione,
Alioune Badara Ndiaye
Issue:
Volume 12, Issue 3, September 2023
Pages:
39-44
Received:
24 March 2023
Accepted:
14 April 2023
Published:
8 September 2023
Abstract: The blast furnace slag comes out of the blast furnace in liquid form at 1500°C. When cooled slowly, in the open air, the crystallized blast furnace slag is obtained. Its uses are generally the same as those of natural rocks. The purpose of this article is to measure the influence of the substitution of Diack basalt aggregates by blast furnace slags (FABRIMETAL slags) on the compressive strength of hydraulic concretes. For this two reference concrete mixtures were used. The first concrete mixture (concrete 1) is mixed with basalt of Diack only, and the second concrete mixture (concrete 5) is mixed with FABRIMETAL slags only. Then basalt substitutions by slags were performed on the concrete 1 at 10%, 25% and 50%. The results obtained showed that slags influence the strength of hydraulic concretes formulated with basalt of Diack by decreasing it. The 28-days compressive strength of concrete 1 drops from 28.8 MPa to 24.8 MPa for 10% substitution, 24.4 MPa for 25% substitution and 21.8 MPa for 50% substitution. However, given the low dispersion of the results obtained (Standard Deviation = 2.28), the substitution of basalt by slag is still possible provided that hydraulic concrete is optimized with additives or a slight cement overdose.
Abstract: The blast furnace slag comes out of the blast furnace in liquid form at 1500°C. When cooled slowly, in the open air, the crystallized blast furnace slag is obtained. Its uses are generally the same as those of natural rocks. The purpose of this article is to measure the influence of the substitution of Diack basalt aggregates by blast furnace slags...
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