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Zhang Q.S.,Anhui and Huaihe River water resources research institute
Advanced Materials Research | Year: 2013

Concrete hollow block after being shaped up is possessed of features like strong shrinkage, poor thermal conductivity and repeated contraction after dampness, which leads to many problems in the use of concrete hollow block wall material. This article elaborates the causes of cracks on concrete hollow block wall from multiple perspectives, such as temperature expansion, air shrinkage, construction quality and design structure, and put forward solutions according to the causes from aspects of production, design, construction and technique improvement. © (2013) Trans Tech Publications, Switzerland.

Zhu L.,Hefei University | Peng J.,Anhui and Huaihe River water resources research institute
Journal of Engineering Science and Technology Review | Year: 2015

A three-dimensional finite-element software program is used in this study to analyze the causes of cracks in an underground garage. Numerous cracks, serious and regular alike, can be found in the underground garage of the Hefei Government Affairs Center. These cracks are mainly located around the central part of the bottom floor within a 44.6-57.8 m radius. To explore the causes of the cracks, two attempts are made. On one hand, on-site crack detection and underground water monitoring are conducted. On the other hand, the finite-element software program ANSYS is adopted to establish a finite-element model for the floor-foundation and connecting beam-foundation soil systems of the underground garage. Furthermore, the influences of the underground foundation, underground water level, soil expansion, and Poisson ratio on the bottom floor are calculated and analyzed. On the basis of the calculation and monitoring results, the following conclusion can be made: underground water is the main cause of the bottom floor cracks because underground water exerts a pushing force from the bottom and causes the expansibility of expansive soil. The study aims to provide a theoretical basis for the treatment of cracking in the hefei government affairs center, and offer a reference for the design, construction, and maintenance of similar projects. © 2015 Kavala Institute of Technology.

Zhang Q.-S.,Anhui and Huaihe River water resources research institute
2011 International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2011 - Proceedings | Year: 2011

Concrete cracking of cement-based materials has been a hot research field, especially for non-load in recent years due to early cracking of particular concern. This paper describes the simulation of the natural environment during construction, the use of flat crack planes, the air in different time periods were pouring concrete slab cracking, observed and recorded later analysis and evaluation of concrete cracking sensitivity of the issue, the results show that: ordinary concrete cracking mix better performance than the ratio of concrete pumping, water conservation was slightly better than the Nature Conservancy, covering the best conservation; plastic stage of the concrete surface pressure change is only the second rub the continuity of the crack, can not resist the final cracking, big slump degree requirements after concrete pouring strictly control the location of cracks should be covered by conservation. © 2011 IEEE.

Song X.-J.,Anhui and Huaihe River water resources research institute | Xu H.-B.,Anhui and Huaihe River water resources research institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

In order to study the mechanical property of cement-soil, the plane strain tests and consolidated drained triaxial (CD) tests are carried out. Characteristics and strength properties of stress-strain curve of cement-soil are discussed. The results show that the stress-strain curve has softening behavior; the softening degree is related to confining pressure and it is obvious under the condition of plane strain state; the strength failure envelopes of both CD test and plane strain test are linear and the Mohr-Coulomb criterion can be applied here; the residual strengths of both CD test and plane strain test increase linearly along with the increase of confining pressure. Moreover, the residual strength of plane strain test is greater than that of CD test; the ratio of residual strength to peak strength increases with the increase of confining pressure and the increasing rate slows down. Under the condition of plane strain, the failure strength is 1.4 to 1.6 times of the CD test result. According to the microstructure and conservation of energy principle, the softening causes of cement-soil are analyzed. The gel material such as cement hydrate is the major factor. The softening characteristic is intensified because of the effect of intermediate principal stress.

Song X.-J.,Anhui and Huaihe River water resources research institute | Wang W.,Shaoxing University | Xu H.-B.,Anhui and Huaihe River water resources research institute
Advanced Materials Research | Year: 2011

Strength characteristics play an important role in mechanic behavior of cement-soil. Laboratory tests on cement-soil with 12% cement ratio and 28 d curing time are conducted by using a new multifunctional triaxial apparatus under fixed spherical pressure condition. Seven series spherical pressures are designed to apply, namely 300 kPa, 400 kPa, 500kPa, 600 kPa, 800 kPa, 1000 kPa, and 1200 kPa. At the same time, seven series consolidation pressures are taken into accounted. Tested data show that: (1) the stress-strain curve of cement-soil is characterized by strain softening, and the soften rate is related to confining pressure; (2) shrinkage or dilatancy of cement-soil volume strongly depend on the value of loaded spherical pressure; (3) failure curve of cement-soil is approximately a line and it agrees with the Mohr-Coulumb criterion. The result of this paper is helpful to the numerical analysis and practical engineering design of cement-soil foundation structures.

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