Papers by Keyword: Limestone Powder

Abstract: A comparative study has been performed on the acid resistance of cement paste exposed to acetic acid (pH=4) and sulfuric acid (pH=2). The pastes are prepared by replacing 30% and 50% cement with limestone powder. Their properties and microstructures are investigated by using strength test, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The paper reveals that erosion extent of pastes depends mainly not only on the pH value of acid solution and the w/b ratio of pastes, but also on the limestone powder mixed that contributes partly to the hydration. Though gypsum and ettringite formations are dominant to the deterioration of pastes exposed to sulfuric acid solution, the degree of decrease for the compressive strength of specimens exposed to sulfuric acid is retarded compared with the specimens exposed to acetic acid. This is attributed to the product of gypsum, which delays the further erosion to the internal paste.

Abstract: This paper primary researched the influence of limestone powder on the workability, the strength performance and the volume stability of self-compacting concrete (SCC). Results showed that the workability of self-compacting concrete was improved greatly by mixing proper limestone powder; besides, limestone powder could improve early age strength of concrete obviously, but had little influence on long age strength; the self-shrinkage of concrete increased as the admixture of limestone powder increased. The content of limestone should be capped at 10% and the optimum mix amount is about 7%.

Abstract: Self-compacting concrete(SCC) is the current trend of new concrete.A variety of materials have been added in it on the purpose of changing the properties of SCC[1].In this paper,three viscous materials of limestone powder, silica fume and metakaolin have been added in SCC to change self-compactability and strength.

Abstract: This paper studies the effects of high-volume composite mineral admixture made of limestone powder and low-quality fly ash on the properties of concrete,and studies the form of attack of cement-based material made of limestone powder at low water-binder ratio under low-temperature sulfate environment.Through experiments, this paper makes clear the workability of fresh concrete and analyzes the law of strength development of concrete. The experimental results indicate that the concrete with high-volume limestone powder as composite mineral admixture has good fresh properties; due to low water consumption per unit volume, medium-and-high-strength concrete can be prepared. As new type concrete mineral admixture, the composite mineral admixture made of limestone powder and low-quality fly ash will play an active role in the sustainable development of concrete industry. After the specimen with the water-binder ratio of less than 0.4 and the limestone powder volume of greater than 20% is soaked in 10% magnesium sulfate solution at low temperature at the age of 200d, gypsum attack-led destruction is caused to the concrete test cube, without thaumasite sulfate attack.

Abstract: In this paper, the high-volume limestone powder and low-quality fly ash are mixed to replace the cement to prepare green concrete, and then its work performance, mechanical properties and microstructure are studied. The test results show that the green concrete prepared by 50% cement and 50% of the mixture of limestone powder and low-quality fly ash has good performance, for its slump loss in 60min is relatively small. The mixture of limestone powder and low-quality fly ash has good composite effect, which endows the concrete the required compressive strength. The scanning electron microscope reflects the good combination of cement paste and the aggregate interface in the concrete, as well as the dense concrete structure.

Abstract: This paper studies the effects of high-volume composite mineral admixture made of limestone powder and low-quality fly ash on the properties of concrete. Through experiments, this paper makes clear the workability of fresh concrete and analyzes the law of strength development of concrete. The experimental results indicate that the concrete with high-volume limestone powder as composite mineral admixture has good fresh properties; due to low water consumption per unit volume, medium-and-high-strength concrete can be prepared. As new type concrete mineral admixture, the composite mineral admixture made of limestone powder and low-quality fly ash will play an active role in the sustainable development of concrete industry.

Abstract: Experimental studies on the properties of cement paste and mortar with the use of limestone powder were carried out. The results show that the replacement with 10% to 30% limestone powder in cement paste can reduce the water requirement for certain flowability. As an inert material, the use of the limestone powder has significant negative effect on the mechanical properties of mortar. However, strength requirement of normal concrete (mortar) can be reached by reducing the water to cementious material ratio, which makes the use of limestone powder as a replacement of cement possible.

Abstract: This thesis first analyzes the necessity for the application of limestone powder produced in Lime Ridge from Xixia County, Henan Province. It also tests the concrete performance with different composition materials and does research on the influence of limestone powder on concrete strength by adding limestone powder instead of fly ash in fly ash concrete. It then finds out the reasonable volume of limestone powder to meet the concrete’s performance, in order to guarantee the scientific and effective use of limestone powder in concrete engineering.

Abstract: The background of research project were firstly introduced as well as current research status of limestone powder in concrete at home and abroad in this study, where current status of limestone demand for cement requirement was analyzed. Then, the mechanism of limestone powder was described, and the influences of limestone powder characteristics on cement performance in Dangziling Village were introduced. It was finally concluded that limestone powder had a good application prospect in cement as a modified material.

Abstract: The influence of limestone powder, air-entraining agent and water binder ratio on chlorine ion (Cl-) penetration resistance of concretes was investigated by rapid Cl- penetration tests. The results show that the fineness of limestone powder is a key factor to Cl- penetration resistance of concrete. It can improve Cl- penetration resistance by introducing super fine limestone powder into concrete. Cl- penetration resistance of concrete increases as curing time increases. The concrete with lower water binder ratio has better Cl- penetration resistance. The introduction of air-entraining agent into concrete can enhance Cl- penetration resistance by improving micro pores structure. The optimum mixing amount is 0.3‰.