Preparation And Application Of Liquid Curing Agent To Nanning Expansive Soilengineering Properties

Expansive soils are those that experience significant volume changes under changing moisture conditions.An expansive soil expands due to the presence of highly reactive clay minerals such as montmorillonite.Problem of expansive soils has appeared as cracking.Severe damages occur to structures like light building,pavements,bridge founded on the expansive soils.The problem with expansive soils has been recorded all over the world.In China,with the development of country construction,more and more construction of buildings and other civil engineering structures have to be carried out on weak or soft soil.It is,therefore,necessary to mitigate the problems posed by expansive soils and prevent cracking of structures.In this paper,it is firstly based on the swelling mechanism of expansive soil and the curing mechanism of all kinds of curing agent,it is evaluated the pros and cons of inorganic ionic,surfactant,polymer with Zeta potential,contact angle,specific surface area.Then got the optimal proportion and liquid curing agent based on selecting Al3+?PAC?PAM?CTMAB to orthogonal test.Finally,the liquid curing agent has been used to Nanning jiahecheng area with laboratory simulation.The main achievements are as follows:(1)Single factor experimental results show that Al3+ has a good curing effect in the inorganic irons,CTMAB has a good curing effect in the surfactant class,PAC has a good curing effect in the inorganic polymer,PAM has a good curing effect in the organic polymer;(2)According to the orthogonal test results,the optimal proportion of liquid curing agent is Al2(SO4)3:CTMAB:PAM:PAC(mass ratio)=33.3:5:0.25:5;(3)Free swelling ratio,liquid limit,plastic limit,plasticity index,Shrinkage limit,swelling rate in 50 kPa,Expansive force of original soil sample with liquid curing agent after curing 7 days into 16.7%,38.5%,26.5%,12%,5.5%,1.45%,3.134 kg,898.90 kPa from 46.2%,32.3%,16.3%,16%,2.9%,7.95%,3.933 kg,819.01 kPa.Expansive soil improved by liquid curing agent has reached specification for design of highway subgrade(JTG E30-2004)project construction requirements;(4)As it is non-toxic,low-toxic,simple construction and environmental friendly,liquid curing agent has practical engineering value.