Engineering Application Research of C35 Pile Foundation Concrete with Artificial Sand Based on Double Mineral Admixture
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摘要: 为研究双掺粉煤灰、矿粉时机制砂C35桩基混凝土的工程应用性能,本文从新拌混凝土的和易性,混凝土早期强度、早期抗裂性能出发,得出适用于工程的机制砂C35桩基混凝土配比,并进行了配比经济性分 析。研究结果表明:(1 )粉煤灰和矿粉的掺入,有利于改善新拌混凝土和易性,但二者掺量均不宜过多。粉煤灰掺量较大时混凝土容易泌水和抓底;矿粉掺量过多时混凝土较黏。用水量和减水剂掺量增加,当二者的掺配比例为1∶2.50或1∶1.30时,机制砂混凝土符合桩基混凝土的和易性要求。(2)双掺粉煤灰、矿粉有利于混凝早期强度增长,保持总掺量35%不变时,粉煤灰、矿粉掺配比例为1∶2.50时,强度发展最优,机制砂混凝土 28 d龄期时能达到C35混凝土试配强度的121%。(3)双掺粉煤灰、矿粉有利于混凝土早期抗裂性能,机制砂混凝土抗裂等级均能达到Ⅳ级要求。(4)对粉煤灰、矿粉掺配比例为1∶2.50的机制砂桩基混凝土进行经济性分析, 其1m3混凝土直接成本较河砂混凝土降低13.2%。Abstract: In order to study the engineering application performance of machine-made sand C35 pile foundation concrete with fly ash and slag powder, this paper starts from the workability of fresh concrete, the early strength of concrete, and the early anti-cracking performance, and the mechanism suitable for engineering is obtained The proportion of sand C35 pile foundation concrete, and the economic analysis of the proportion. The research results show that: (1) The mixing of fly ash and mineral powder is beneficial to improve the workability of fresh concrete, but the amount of both should not be excessive. When the amount of fly ash is large, the concrete is easy to bleed and scratch the bottom; when the amount of slag is too much, the concrete is sticky. The water consumption and water reducing agent content increase. When the mixing ratio of the two is 1:2.50 or 1:1.30, the machine-made sand concrete meets the workability requirements of pile foundation concrete. (2) The double mixing of fly ash and mineral powder is conducive to the early strength growth of concrete. When the total content of 35% is kept unchanged, when the mixing ratio of fly ash and mineral powder is 1:2.50, the strength development is optimal, and the machinemade sand at 28 d age, the concrete can reach 121% of the trial mix strength of C35 concrete. (3) The double addition of fly ash and mineral powder is beneficial to the early anti-cracking performance of concrete, and the anti-cracking grade of machine-made sand concrete can reach the requirement of grade IV. (4) The economic analysis of the machine-made sand pile concrete with a mixing ratio of fly ash and mineral powder of 1:2.50 shows that the direct cost of 1 m3 concrete is reduced by 13.2% compared with river sand concrete.
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Key words:
- machine-made sand /
- pile foundation concrete /
- mineral admixture /
- workability /
- strength /
- crack resistance /
- economy
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