本文選題：鋼纖維聚合物結(jié)構(gòu)混凝土 + 環(huán)境疲勞�。� 參考：《華南理工大學(xué)》2014年碩士論文

【摘要】：工程實(shí)踐表明，采用普通的高強(qiáng)混凝土材料，，雖然提高了混凝土結(jié)構(gòu)的強(qiáng)度，卻使其脆性問題更加突出。為了改善普通高強(qiáng)混凝土的韌性及抗裂性能，本課題組以在建的某高速公路某特大橋?yàn)楣こ桃劳�，從材料的力學(xué)性能著手，對(duì)已有自主知識(shí)產(chǎn)權(quán)的“鋼纖維增強(qiáng)聚合物改性混凝土”進(jìn)行二次開發(fā)，研發(fā)了一種能夠應(yīng)用于大跨度橋梁上部結(jié)構(gòu)的新型結(jié)構(gòu)材料——鋼纖維聚合物結(jié)構(gòu)混凝土（SFPSC）。為了進(jìn)一步探討該類新材料的耐久性能，本文考慮我國南方和沿海地區(qū)橋梁實(shí)際服役時(shí)的濕熱環(huán)境影響，對(duì)其環(huán)境疲勞性能進(jìn)行了實(shí)驗(yàn)研究，研究成果對(duì)于提高大跨度混凝土橋梁結(jié)構(gòu)的耐久性具有重要的科學(xué)意義和工程應(yīng)用價(jià)值。本文的主要研究?jī)?nèi)容和結(jié)論如下： 1)“鋼纖維聚合物結(jié)構(gòu)混凝土（SFPSC）”的研制。根據(jù)某高速公路橋梁建設(shè)的實(shí)際需求，通過配合比設(shè)計(jì)、材料組分分析及基本力學(xué)性能實(shí)驗(yàn)，研制出一種與現(xiàn)有高強(qiáng)混凝土（例如C55混凝土）的強(qiáng)度相仿，但具有更優(yōu)越的抗裂、抗疲勞性能的改性混凝土材料。 2)在不同濕熱條件下對(duì)SFPSC試件預(yù)處理后（50℃和80%RH；50℃和90%RH；50℃和95%RH），實(shí)施了三點(diǎn)彎曲疲勞實(shí)驗(yàn)，獲得了SFPSC梁的S~N曲線；根據(jù)疲勞強(qiáng)度理論及假定，推導(dǎo)了SFPSC的環(huán)境疲勞壽命表達(dá)式。對(duì)于該表達(dá)式中的常系數(shù)，由環(huán)境疲勞實(shí)驗(yàn)數(shù)據(jù)來確定。研究結(jié)果表明，利用該公式可有效地、方便地推定在亞熱帶地區(qū)濕熱氣候條件下SFPSC的疲勞壽命及其疲勞極限。 3)分析了環(huán)境疲勞實(shí)驗(yàn)中SFPSC試件的載荷～跨中撓度曲線和疲勞壽命～跨中撓度曲線，發(fā)現(xiàn)了SFPSC三點(diǎn)彎曲梁跨中撓度的三階段式變化規(guī)律。通過對(duì)實(shí)驗(yàn)數(shù)據(jù)進(jìn)行無量綱處理，得到了各實(shí)驗(yàn)梁的相對(duì)循環(huán)次數(shù)～相對(duì)撓度曲線，并探討了應(yīng)力水平和不同濕熱環(huán)境預(yù)處理對(duì)試件撓度曲線影響的規(guī)律。 4)利用跨中撓度對(duì)試件損傷變量D進(jìn)行描述，并推導(dǎo)出基于損傷變量D的疲勞壽命預(yù)測(cè)公式。研究結(jié)果表明，SFPSC梁疲勞破壞時(shí)損傷量的推定值為0.85。在此基礎(chǔ)上，通過少量非破壞性疲勞實(shí)驗(yàn)數(shù)據(jù)就可方便地對(duì)SFPSC梁的疲勞壽命進(jìn)行預(yù)測(cè)。
[Abstract]:The engineering practice shows that the brittleness of concrete structure is more prominent though the strength of concrete structure is improved by using ordinary high strength concrete material. In order to improve the toughness and crack resistance of ordinary high strength concrete, our group based on a large bridge of a highway under construction, started from the mechanical properties of the material. Based on the secondary development of "steel fiber reinforced polymer modified concrete", a new structural material, steel fiber polymer structure concrete, which can be applied to the superstructure of long-span bridges, is developed. In order to further study the durability of the new materials, the environmental fatigue properties of bridges in southern and coastal areas of China are studied experimentally, considering the effect of wet and thermal environment on the actual service. The research results have important scientific significance and engineering application value for improving the durability of long span concrete bridge structure. The main contents and conclusions of this paper are as follows: 1. Development of Steel Fiber Polymer structure concrete (SFPSC). According to the actual demand of a highway bridge construction, through mix ratio design, material component analysis and basic mechanical performance experiment, a kind of strength of high strength concrete (such as C55 concrete) is developed, which is similar to that of the existing high strength concrete (for example, C55 concrete). But with better crack resistance, fatigue resistance of modified concrete materials. 2) SFPSC specimens were pretreated at 50 鈩

本文編號(hào)：1813741