Investigation of ion chelator and mineral admixtures improving salt-frost resistance of cement-based materials

Cement as the binding agent in the production of concrete can be replaced with active mineral admixtures. Biofuel combustion fly ash is one of such admixtures. Materials used for the study: Portland cement CEM I 42.5 R, sand of 0/4 fraction, gravel of 4/16 fraction, biofuel fly ash, superplasticizer, water. Six compositions of concrete were designed by replacing 0%, 5%, 10%, 15% 20%, and 25% of cement with biofuel fly ash. The article analyses the effect of biofuel fly ash content on the properties of concrete. The tests revealed that the increase of biofuel fly ash content up to 20% increases concrete density and compressive strength after 7 and 28 days of curing and decreases water absorption, with corrected water content by using plasticizing admixture. It was found that concrete where 20% of cement is replaced by biofuel ash has higher frost resistance.

Download Full-text

Minimum Water Requirement Method for High-Performance Sulphoaluminate Cement-Based Materials

Advances in Materials Science and Engineering ◽

10.1155/2019/4187342 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11

Author(s):

Hong-ping Zhang ◽

Pei-kang Bai ◽

Jian-hong Wang ◽

Yan-li Dong ◽

Yun-shan Han

Keyword(s):

Cement Paste ◽

High Performance ◽

Steel Slag ◽

Cementitious Materials ◽

Water Requirement ◽

Mineral Admixtures ◽

Poor Correlation ◽

Sulphoaluminate Cement ◽

Cement Based Materials ◽

Orthogonal Tests

In this work, we propose the use of steel slag instead of slag powder, in addition to fly ash and silica fume, to obtain high-performance sulphoaluminate cement-based materials. According to the closest-packing theory and on the basis of the minimum water requirement test, the influence of mineral admixtures on the minimum water requirement was evaluated for sulphoaluminate composite system paste. The optimal composition of the cementitious materials was thus determined. Orthogonal tests were used to assess the validity of this ratio. The correlation between minimum water requirement and the standard consistence was not only analyzed in the system of the minimum water requirement method decided but also in the complicate system of the orthogonal tests determined. Experimental results show that the influence of steel slag on the minimum water requirement is the largest in composite cement paste; minimum water requirement and standard consistency have a good correlation; the cement paste designed with the optimum composite had the highest strength of all the tested materials, but minimum water requirement and strength have a poor correlation in the orthogonal tests. We demonstrate that standard consistency evaluation can replace the minimum water requirement method to determine the optimum ratio of cement mineral admixtures. The proposed method not only simplifies the process but also makes the method more scientific.

Download Full-text

Effects of chemical and mineral admixtures on the foam indexes of cement-based materials

Case Studies in Construction Materials ◽

10.1016/j.cscm.2019.e00232 ◽

2019 ◽

Vol 11 ◽

pp. e00232

Author(s):

Hai Huang ◽

Qiang Yuan ◽

Dehua Deng ◽

Jianwei Peng ◽

Yanling Huang

Keyword(s):

Mineral Admixtures ◽

Cement Based Materials

Download Full-text

Research on Polypropylene Fiber and Mineral Admixtures on Fluidity of Cement-Based Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.328-330.1301 ◽

2011 ◽

Vol 328-330 ◽

pp. 1301-1304

Author(s):

Xue Fei Li ◽

Tao Guo

Keyword(s):

Fly Ash ◽

Cement Mortar ◽

Polypropylene Fiber ◽

Maximum Flow ◽

Mineral Admixture ◽

Mineral Admixtures ◽

Polypropylene Fibers ◽

Intensity Level ◽

Reticular Fibers ◽

Cement Based Materials

The purpose of this paper is based on the cement-based materials by adding fibers and mineral admixtures for composite, to cement the improvement of liquidity. Experiment with the intensity level of 42.5 ordinary portland cement, by adding polypropylene fibers, slag and fly ash cement mortar as a mineral admixture, the production of cement mortar matrix for the test, were conducted on a variety of mix Fluidity test. Experiments show that the addition of polypropylene fiber is not conducive to the mobility of mortar, especially monofilament fiber was more obvious than the reticular fibers. To join the slag, fly ash, mortar fluidity increased, indicating that slag and fly ash added to improve the workability of cement-based materials. When the fiber content reaches the maximum degree of maximum flow, indicating that slag, fly ash and polypropylene fibers will increase the combined effect of fluidity value. This innovation is obtained by adding fiber cement-based materials for toughening effect, with the use of mineral admixture can improve the overall performance of cement based materials, with further research and promotion value.

Download Full-text

Role of Chemical and Mineral Admixtures on the Physical Properties and Frost-Resistance of Recycled Aggre-gate Concrete

ACI Materials Journal ◽

10.14359/398 ◽

1998 ◽

Vol 95 (5) ◽

Cited By ~ 5

Keyword(s):

Physical Properties ◽

Frost Resistance ◽

Mineral Admixtures ◽

Aggre Gate

Download Full-text

The fractal characteristics of pore size distribution in cement-based materials and its effect on gas permeability

Scientific Reports ◽

10.1038/s41598-019-53828-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Jie Zhu ◽

Rui Zhang ◽

Yang Zhang ◽

Fa He

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Pore Diameter ◽

Gas Permeability ◽

Fractal Dimensions ◽

Mineral Admixtures ◽

Pore Surface ◽

Surface Fractal ◽

Cement Based Materials ◽

Fractal Characteristics

AbstractTo study the influence of the pore structure of cement-based materials on macroscopic features (gas permeability), mercury intrusion porosimetry (MIP) and nitrogen adsorption (NA) were applied to 8 groups of paste and mortar samples (including adding mineral admixtures or not and standard or sealed curing conditions). Pore size distribution has a great influence on gas permeability. By calculating pore surface fractal dimensions based on Zhang’s fractal model, the obvious fractal characteristics of micropores (<100 nm) and macropores (> 105 nm) have been found. The pore diameter of the paste is mostly distributed in the micropores, and the average critical pore diameter is 82 nm. For mortar, the pore diameter is mostly distributed in the micropores and transition pores, and the average critical pore diameter is 121 nm, which means that the seepage pore diameters of the paste and mortar are 82 nm and 121 nm, respectively. The pore surface fractal dimensions of the visible pores are larger than those of the micropores, and there is an inverse relationship between the pore surface fractal dimensions and gas permeability. An important guide for engineering production is to use standard curing and add mineral admixtures to mortar materials to improve the impermeability as much as possible, while a contrary condition exists for paste materials.

Download Full-text

Distribution Map of Frost Resistance for Cement-Based Materials Based on Pore Structure Change

Materials ◽

10.3390/ma13112509 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2509

Author(s):

Nguyen Xuan Quy ◽

Takumi Noguchi ◽

Seunghyun Na ◽

Jihoon Kim ◽

Yukio Hama

Keyword(s):

Prediction Model ◽

Pore Structure ◽

Frost Resistance ◽

Frost Damage ◽

Structure Change ◽

Quantitative Prediction ◽

Weather Data ◽

Distribution Map ◽

Cement Based Materials ◽

Damage Risk

This paper presents a prediction method and mathematical model based on experimental results for the change in pore structure of cement-based materials due to environmental conditions. It focuses on frost damage risk to cement-based materials such as mortar. Mortar specimens are prepared using water, ordinary Portland cement, and sand and the pore structure is evaluated using mercury intrusion porosimetry. New formulas are proposed to describe the relationship between the pore structure change and the modified maturity and to predict the durability factor. A quantitative prediction model is established from a modified maturity function considering the influences of environmental factors like temperature and relative humidity. With this model, the frost resistance of cement-based materials can be predicted based on weather data. Using the prediction model and climate data, a new distribution map of frost damage risk is created. It is found that summer weather significantly affects frost resistance, owing to the change in pore structure of cement-based mortar. The model provides a valuable tool for predicting frost damage risk based on weather data and is significant for further research.

Download Full-text