At present, the mineral admixture has become an indispensable component of modern concrete, it has been generally agreed that commonly used mineral admixtures (slag, fly ash, silica fume, etc.) used in concrete can play a concrete performance Significant improvement. Travertine Stone The incorporation of fly ash, mineral powder and other mineral admixtures can effectively improve the workability of concrete. The development of high-performance concrete, fly ash and slag and other commonly used admixture of large-scale use, resulting in the market fly ash, mineral powder and other mineral admixture transport costs increase, Travertine Stone the supply increasingly tense. Resulting in the current shortage of mineral admixtures of the phenomenon, the use of limestone powder to do concrete admixture, has the following meaning: an effective solution to the shortage of resources commonly used in China, the contradiction between supply and demand to ease. Chongqing local limestone rich in resources, Travertine Stone quality and cheap, which will fundamentally solve the shortage of admixture situation. But also can fully guarantee the sustainable development of regional environment, make full use of local resources to promote China's building materials industry forward.
With the increase in limestone powder content, concrete slump and 1h slump results in Table 2. It can be seen from Table 2 that as the limestone powder content increased from 0 kg / m3 to 90 kg / m3, the initial slump of concrete was maintained between 210 mm and 250 mm, Travertine Stone and the slump increased from 170 mm to 240 mm. With the increase of limestone powder content, the slump loss decreased from 40mm in group 1 to 10mm in group 5, and the increase of limestone powder content significantly reduced the slump loss of concrete. Among them, limestone powder content is greater than 50% of mineral admixtures, 1h slump loss significantly reduced.
With the increase of limestone powder content, Travertine Stone the slump of concrete slag becomes larger and the slump loss decreases significantly, which is mainly due to the morphological effect and filling effect of limestone powder. The surface of dense and smooth limestone powder particles dispersed in the cement particles, play a role in dispersant, can promote the early hydration of cement particles of the solution, thereby improving the performance of concrete. The limestone powder is finer and has a low surface area, Travertine Stone thus increasing the flowability of the mixture. Because limestone powder is smaller than the fineness of cement particles, it can fill the gap between cement and fly ash and play the role of filling skeleton, thus improving the workability of concrete.
With the increase of the amount of fly ash instead of fly ash, the early strength did not change significantly with the amount of different gels under the content of limestone powder, and the strength of the later stage increased with the increase of the content of stone powder. Travertine Stone decline. As the limestone powder activity is relatively low, the late strength growth rate is not as good as fly ash, so the stone powder content increases, the late strength growth rate decreased slightly.