Experimental Study On Properties Of Concrete Early Thaw Environment

Low winter temperatures in many parts of Tibet, for various reasons, inevitable to concrete construction in the winter. Low temperature environment construction, concrete is prone to early frost damage. People who have studied the construction of concrete in winter, have reached a consensus: Make sure the concrete before frost early frost reaches critical strength of concrete is the most effective way to prevent the occurrence of larger damage, age appropriate pre-curing concrete can protect late performance. So for the study of early frost resistance shortest pre-curing period and its influencing factors become critical strength antifreeze key content, research shows that many scholars, critical strength of concrete frost and freezing temperatures affected by the intensity level is relatively large.For winter concrete construction, development and performance of its early formation of the structure received restricted, due to lower temperatures slow the hydration of cement, water freezes on the pore walls produce a variety of pressure, so that the internal structure of the formation of large concrete cracks and pore connectivity, low temperature environment to concrete caused serious damage; early frost damage caused to the concrete, this damage even after standard curing late can not be fully restored, early frost caused permanent damage to the concrete. The entire life of the concrete into the early stages and later stages, this paper focuses on the effects of early environment on early freeze-thaw resistance of concrete and durability of late.Durability is closely related to its early performance, good early performance of concrete Concrete, which tend to have better durability, is an important indicator of the compressive strength of concrete, practical projects commonly 28 d compressive strength of concrete as a construction quality acceptance criteria, the actual project Experience has shown that: 28 d qualified concrete compressive strength, its durability is not necessarily satisfactory late, 28 d age concrete compressive strength as construction quality acceptance criteria seem a little too simple, it is necessary for construction quality acceptance criteria of concrete research.In summary, the main contents of this paper include the following aspects:(1) the strength of the critical factors antifreeze research;(2) In the winter construction conditions, the impact of curing conditions on the early performance of concrete;(3) In the winter construction conditions, the impact of post-curing conditions on the durability of concrete energy;(4) late winter frost resistance of concrete construction and post-penetration resistance relationship of the study;(5) the performance of early and late winter construction of concrete durability can study the relationship between, on this basis, the construction quality acceptance criteria of concrete research.