1. Figure 3. SEM observation of limestone filler.
Material & Methods
Cement used in this study is the CEM II/A 42.5.
1. Cement
81% Clinker
8% Limestone
6% Pozzolana
5% Gypsum
The chemical admixture used resulting from the technology of chemical products development and the new generation of superplasticizer based on acrylic copolymer.
2. Chemical admixture
The limestone filler used is a finely divided limestone, obtained by crushing limestone rocks from Bechar Mountain (south side). The limestone addition is a hard greyish dry product composed mainly by carbonate (78.90%).
3. Limestone filler
Bechar City (southwest of Algeria) benefit of a large number of building materials, the main choice is the nearly site, the sand used is the principal existing sand in this region. To attain the desired objectives based on environmental aspect the sand used in this study is calcareous crushed sand
4. Sand
Figure 4. The cumulative sieving curve of sand.
The results of compression tests according to the temperature show clearly the increase of the compressive strength (around 20%) based on the value obtained for specimen saturated with water. The increase on resistance of cement matrix can be attributed to two phenomena: the first one is the effect of capillary suction. The second phenomenon is related to water gradients created in the specimen during the desiccation process: the edges of the specimen shrink in the direction of the heart of this one, causing a confinement of the heart of the specimen.
Introduction
This research is based on the use of the local material existing in very large quantity and available locally, the main aspect are economic and environmental parts, using local materials might decrease the price of concrete. The results obtained in this study summarize up the importance of the mineral admixture mainly limestone filler and its influence on the behaviour of batch at fresh and hardened state, than finally the mechanical behaviour of mortar. In addition, this study summarize up the importance of the curing temperature at 55°C during the development of the mechanical characteristics.
Figure 1. CO2 emission by industry in civil engineer domain.
Environnement
Waste Valorisation
Economy
Figure 2. Waste management triangle.
ICOCEE - Cappadocia 2015
Conclusions
The results demonstrated the heterogeneity of the granular mixture and the overlap between physical and mechanical parameters with pouzzolanique binding aspect of changing the hydration of cement at curing temperature. The granular distribution of sand allows the filling of significant parts of voids between grains of sand, while the limestone filler might fulfil the vacuums between sand and cement grains, the high density of the product resulting form limestone hydration might be the reason of the good durability of concrete whit high percentage of fine limestone.
The authors grateful acknowledge to Sika Aldjazair stuff, especially Mr Billal Announ and Mm Khedim Khadidja (R&D Department) for providing chemical admixture.
Also The author’s grateful Mer Bouzid Abdallah for SEM characterization.
Acknowledgement
Finally, the concrete is the most material even used in the word, its large consummation result with a number of environmental and economic problem related to the waste resulting from the manufactories of the concrete. For this reason, the aim desired now by the field of civil engineer or construction domain, is the introduction in concrete the maximum of waste material in concrete composition taking in consideration the environmental milieu.
Results & Discussion
By its high specific surface it is clearly remarkable that the addition of limestone filler by substitution decrease down the workability of the composition, where the limestone filler is characterised by its high amount of water absorption.
To attain the desired objective we choose the addition of limestone by substitution by cement based on economics’ and environmental consideration.
Figure 5. Variation of workability as function of limestone substitution.
Figure 7. SEM microstructure of concrete with 0% substitution at 10µm.
Figure 8. SEM microstructure of concrete with 25% substitution at 10µm.
The designation finely divided mineral admixture allows to the limestone filler a high water demand due to its large specific surface, therefore we were forced to increase the demand for water to maintain plastic workability. otherwise , the reduction of the fresh density decreases because of thehydration mode of the limestone, where it is noted that the progression of substitution increases the percentage of portlandite in the crystalline structure of the past, that in effect which explain the slowing down the hydration phenomenon of concrete binder.
Figure 6. Variation of the density as function of limestone substitution.
1. Effect of limestone filler on the workability of mortar
2. Effect of limestone filler on the density of mortar
3. Effect of limestone filler on the crystalline structure of mortar
Contribution to the amelioration of Mechanical Behaviour of Mortar Based on limestone Mineral Admixture substitution at curing Temperature
Ilham Aguida Bella, Aîssa Asroun and Nabil Bella
Department of civil engineer, Technology Faculty, Mohammed TAHRI Bechar University,
P. Box 417 Bechar 08000, ALGERIA
THE INTERNATIONAL CONFERENCE ON
CIVIL AND ENVIRONMENTAL ENGINEERING
20 – 23 May 2015, Nevsehir, TURKEY