低温/常温养护下混凝土的本构模型和抗爆试验

doi:10.12382/bgxb.2022.1019

摘要/Abstract

摘要：

混凝土材料的力学性能与养护环境紧密相关,受施工环境的限制,部分混凝土构件需要在高海拔、高寒等低温环境下浇筑成型。为研究低温/常温养护下混凝土的力学性能和抗爆能力,开展多组低温/常温养护下混凝土材料的单轴抗压测试试验。结合单轴抗压测试试验结果引入与养护时间相关的损伤演化函数,修正塑性流动因子,并建立低温/常温养护下混凝土的本构模型。通过混凝土的爆炸冲击试验对比常温养护和低温养护下混凝土的抗爆性能。研究结果表明:低温养护下混凝土材料的抗压强度约为常温养护下的34.6%~56.8%,且混凝土的抗压强度与养护时间呈正相关关系,与试件内部含水率呈负相关关系;新建立的混凝土本构模型可以对低温/常温养护下混凝土的力学性能进行有效预测;低温养护成型后混凝土的抗爆性能有所降低,但仍具有明显的抗爆能力。

关键词: 混凝土, 低温/常温养护, 抗压强度, 含水率, 本构模型, 抗爆性能试验

Abstract:

The mechanical properties of concrete materials are closely related to the curing environment. Limited by the construction environment, some concrete structures are poured and formed at high altitudes or in cold, low-temperature conditions. In this work, several uniaxial compressive tests are conducted on concrete specimens cured at both low and room temperatures to study their mechanical properties and blast resistance. Based on the results of these tests, the damage evolution function related to the length of curing is introduced, the plastic flow factor is modified and the constitutive model of concrete under low/room temperature curing is established to predict the mechanical properties of concrete. Blast impact tests of concrete are conducted to compare the blast resistance of concrete blocks under low/room temperature curing. The research results show that: the compressive strength of concrete materials under low-temperature curing is about 34.6%~56.8% of that under room temperature curing. Compressive strength is positively correlated with the length of curing and negatively correlated with the internal moisture of the specimens. The mechanical properties of concrete under low/room temperature curing can be effectively predicted by the established concrete constitutive model. The blast resistance of concrete formed by low-temperature curing is reduced, but it still exhibits notable blast resistance capabilities.

Key words: concrete, low/room temperature curing, compressive strength, internal moisture, constitutive model, blast resistance test

中图分类号:

O385
TJ012.4

宁建国, 杨帅, 李玉辉, 许香照. 低温/常温养护下混凝土的本构模型和抗爆试验[J]. 兵工学报, 2023, 44(10): 2932-2943.

NING Jianguo, YANG Shuai, LI Yuhui, XU Xiangzhao. Constitutive Model and Blast Resistance Test of Concrete under Low/Room Temperature Curing[J]. Acta Armamentarii, 2023, 44(10): 2932-2943.

图/表 17

图1 试验用混凝土试件

Fig.1 Concrete specimens for testing

图2 试验装置

Fig.2 Test equipment

图3 常温养护下混凝土破坏形貌

Fig.3 Damage morphologies of concrete under normal temperature curing

图4 低温养护(-10℃)下混凝土破坏形貌

Fig.4 Damage morphologies of concrete under low-temperature curing (-10℃)

表1 常温养护下混凝土的抗压强度

Table 1 Compressive strength of concrete undernormal temperature curing

试件编号	试件质量/g	试件尺寸 (长×宽×高)/ mm³	抗压强度/ MPa	标准抗压强度/ MPa	平均抗压强度/ MPa
30-1	2288	99×99×101	26.28	24.97
30-2	2289	99×100×99	29.38	27.91
30-3	2265	99×101×99	30.91	29.36
30-4	2242	100×100×100	29.60	28.12	29.40
30-5	2291	98×100×100	31.87	30.28
30-6	2230	98×102×97	29.74	28.25
30-7	2231	100×101×99	36.80	34.96
30-8	2267	99×100×100	33.01	31.36

图5 标准抗压强度与常温养护时间关系

Fig.5 Relationship between standard compressive strength and normal curing time

图6 低温/常温养护下抗压强度对比

Fig.6 Comparison of compressive strengths under low-temperature/normal temperature curing

表2 不同养护天数下试件参数变化

Table 2 Variation of specimen parameters under different curing days

养护天数/d	质量损失/g	含水率降幅/%	抗压强度/MPa
	0	0	11.67
28(低温)	0	0	8.57
	0	0	10.25
	92	4.06	11.70
40(常温)	63	2.63	13.33
	66	2.79	13.61
	74	3.19	14.64
47(常温)	78	3.30	14.63
	95	4.08	14.50
57(常温)	121	5.33	14.68
	125	5.52	14.67
	147	6.17	17.99
71(常温)	141	5.95	15.82
	149	6.13	17.95
	167	6.62	16.50
85(常温)	180	7.62	15.43
	169	6.78	16.86
99(常温)	179	7.05	16.06
	183	7.42	17.41

图7 不同养护工况下应力-应变曲线

Fig.7 Stress-strain curves under different curing conditions

图8 标准抗压强度与含水率降幅关系

Fig.8 Relationship between standard compressive strength and water content drop

图9 低温养护28d后混凝土的损伤演化规律

Fig.9 Damage evolution law of concrete after low-temperature curing for 28 days

表3 不同养护时间下的混凝土材料参数

Table 3 Parameters of concrete materials after subjecting to different lengths of curing

试验	E/GPa	σ_s0/MPa	ε_m	σ_m/MPa
T28	6.035	10.876	2.4×10^-3	12.281
T57	11.276	12.146	1.6×10^-3	15.405
T85	19.724	14.708	1.2×10^-3	17.368

表4 本构模型中的参数

Table 4 Parameters in the concrete constitutive model

试验	a	b	η	h	n_p
T28	102.34	2.69	3.74×10^-5	5.78×10³
T57	192.56	2.03	2.25×10^-5	6.12×10³	2.1
T85	289.47	1.78	2.18×10^-5	6.47×10³

图10 不同养护时间下应力-应变关系对比图

Fig.10 Comparison of stress-strain relationship with different curing lengths

图11 试验现场布置图

Fig.11 Test setup

图12 常温养护下混凝土块体爆炸后效图

Fig.12 Explosive effects of concrete block under room temperature curing

图13 低温养护下混凝土块体爆炸后效图

Fig.13 Explosive effects of concrete block under low-temperature curing

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