Papers by Keyword: Cement Stabilized Aggregate

Abstract: Stabilized aggregate containing Special cement with desulfurization residue is characterized by long setting time, slight expansion, and retarded inducing strength, therefore, research was conducted on its performance. Research results show that when on 28d and compared with stabilized aggregate of PC 32.5 cement, the stabilized aggregate of special cement’s unconfined compressive strength increased by 17%, dry shrinkage energy anti-cracking coefficient by 78%, whereas resilient modulus and splitting strength indicated small changes, whilst the performance of special cement materials showed vast improvements through significant increases in the stabilized aggregate’s mechanic and shrinkage performances. The strength of stabilized aggregate from special cement containing desulfurization residue mainly comes from AFt, Ca(OH)₂ and the C-S-H gel formed in the hydration of the special cement and also with the continuing dissolution of CaSO₃. The resultant new phase of C₃A•CaSO₃•11H₂O is formed after the 7d hydration period. Desulfurization residue in cement consists of a significant amount of Ca(OH)₂, therefore, the alkali content in the hydration phase is maintained at a very high level, which affects the consistency of ettringite through the formation of higher-quality needle-like crystals during hydration, which in turn is beneficial to reduce the base material’s self-shrinkage capability and improve its anti-cracking performance. At the same time, stimulated by Ca(OH)₂-CaSO₄, the hydration of fly ash and ground granulated blastfurnace slag is also improved, which is advantageous for further improving the cement’s strength and anti-cracking performance at a later stage in the curing process.

Abstract: A series of parametric tests have been conducted to investigate the effect of curing period and cement content of the specimen on fracture energy of cement stabilized aggregate. By means of three-point bending method, the fracture energy of cement stabilized aggregate was measured. Four specimen curing periods (14 d, 28 d, 60 d and 90 d) and four different cement contents (4%, 5%, 6% and 7%) were used. The results indicate that the fracture energy of cement stabilized aggregate is increasing with the increase of specimen curing period. Besides, with the increase of cement content, there is a tendency to decrease in the fracture energy of cement stabilized aggregate. The ability of cement stabilized aggregate to resist crack propagation becomes weaker and weaker with the increase of cement content.

Abstract: The aim of this study was to study the effect of curing period and cement content of the specimen on flexural strength and flexural modulus of elasticity of cement stabilized aggregate. Four specimen curing periods (7 d, 14 d, 28 d and 60 d) and four different cement contents (4%, 5%, 6% and 7%) were used. The results indicate that the flexural strength and flexural modulus of elasticity of cement stabilized aggregate are increasing with the increase of specimen curing period. Besides, with the increase of cement content, there is a tendency to increase both in the flexural strength and flexural modulus of elasticity of cement stabilized aggregate. The actual cement content should be chosen according to the actual condition of the project.

Abstract: Laboratory tests were conducted to evaluate the performance of cement stabilized “skeleton-dense structure” aggregate and conventional “suspended-dense structure” aggregate. In this study, both of the aggregates above were stabilized by cement with different cement content (2%, 3%, 4%, 5% and 6%). Performances of the prepared specimens were studied in terms of compaction property, 7 day unconfined compressive strength (UCS), thermal shrinkage coefficient and 30 min erosion quantity. Results indicated that the maximum dry density of cement stabilized “skeleton-dense structure” aggregate is bigger than that of cement stabilized “suspended-dense structure” aggregate slightly. On the contrary, the optimum moisture content of the former is slightly smaller than that of the latter one. Along with the increase of cement content, the 7 day UCS and thermal shrinkage coefficient of cement stabilized two aggregates were all increase, and 30 min erosion quantity of cement stabilized two aggregates were all decrease. At the same cement content level, the 7 day UCS of cement stabilized “skeleton-dense structure” aggregate is greater than that of cement stabilized “suspended-dense structure” aggregate, and the thermal shrinkage coefficient and erosion quantity in 30 min of the former is smaller than that of the latter.